Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
Loading...
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Digestive tract is the same as alimentary tract, and includes the entire passage for food through the body, including mouth, oral cavity (both vestibule of mouth and cavitas oris propria), oropharynx, esophagus, stomach, duodenum, jejunum, ileum, colon, rectum, and anal canal.
Digestive system includes the digestive tract, as well as the associated organs of digestion, including tongue, teeth, salivary glands, liver, exocrine pancreas, gallbladder, and biliary tract.
Gastrointestinal tract has two meanings in common usage. One that does and one that does not include the esophagus. The usage that includes the esophagus would more correctly be named esophago-gastrointestinal tract. Endoscopists frequently use this meaning, even though it is contrary to some dictionary definitions and does not follow strict lexical interpretation (which does not include the esophagus).
Upper gastrointestinal (GI) tract. When describing upper GI bleeding and upper GI radiographic and endoscopic procedures the upper GI tract includes the esophagus, stomach, and duodenum. The upper GI tract does not include the more restricted stomach-intestine entity.
Lower gastrointestinal (GI) tract. When describing lower GI bleeding, lower GI radiographic and endoscopic procedures, and lower GI output from ileostomies and colostomies, the lower GI tract includes the jejunum, ileum, cecum, colon, rectum and anal canal. The ligament of Treitz may be used as the division between upper and lower GI tracts (and the division between the duodenum and jejunum).
Also, since the upper GI tract is said to end at the duodenum-jejunum junction, and there is no concept meaning middle GI tract, the jejunum can be inferred to be in the lower GI tract.
See J Vasc Interv Radiol 9:747 for an example of inclusion of the jejunum and distal tract as part of the lower GI tract.
The SNOMED CT concepts 119253004 |Upper aerodigestive tract structure (body structure)| and 361922007 |Entire upper aerodigestive tract (body structure)| have the meaning based on the following reference: Cancers of the upper aerodigestive tract constitute approximately 4% of all malignancies. These include cancer of the lip, tongue, major salivary glands, gums and adjacent oral cavity tissues, floor of the mouth, tonsils, oropharynx, nasopharynx, hypopharynx and other oral regions, nasal cavity, accessory sinuses, middle ear, and larynx (Upper aerodigestive tract cancers, Cancer 1995 Jan 1;75 (1 Suppl): 147-53). This definition matches the tumors included in the CAP Cancer Checklist for upper aerodigestive tumors. The esophagus, or at least the cervical esophagus, may be included, but not in SNOMED CT.
Biliary tract includes the gallbladder, intrahepatic and extrahepatic bile ducts, and common bile duct. It does not include the liver. SNOMED CT uses biliary system as a synonym for biliary tract. SNOMED CT has another concept that does include the liver, 732049009 |Entire liver and biliary system (body structure)|.
Mouth has several different meanings including mouth region, oral region of the face, and rima oris.
Mouth region includes structures surrounding the oral cavity, as well as structures of the oral region of the face.
Use mouth region for most disorders with a finding site of mouth.
Oral region of face includes the skin and subcutaneous tissue of the lips and perioral region, the orbicularis oris muscle, and the vessels and nerves in these structures.
Rima oris is the opening of the mouth.
The four regional parts of the tongue are the ventrum (inferior surface), dorsum, root, and body. The root of the tongue is the posterior third, the dorsal surface of which forms the anterior wall of the oropharynx. The root of the tongue rests on the floor of the mouth. The nerves and vessels that supply the intrinsic muscles of the tongue traverse the root of the tongue.
The terms colorectal and colorectum , commonly used by pathologists, are included in descriptions for concepts referring to neoplasms modeled with 1285733009 |Structure of cecum and/or colon and/or rectum (body structure)|. 1285733009 |Structure of cecum and/or colon and/or rectum (body structure)| is needed because neoplasms are the same from the cecum to rectum and are considered as a group in cancer synoptic reporting protocols. Note, there is no consensus concerning the definition of colon in the literature and between different domains.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Concepts from the Morphologic Abnormality hierarchy should not be used in place of concepts from the Clinical Findings hierarchy, even though they appear to refer to similar clinical situations.
For example
4147007 | Mass (morphologic abnormality)| is not a finding, but 300848003 | Mass of body structure (finding)| is a finding
Morphologies are used as the values of the defining attributes of findings and procedures. Findings are used to represent the combination of a morphology and a location.
For example
300923002 | Cyst of scalp (disorder)| represents cystic type of morphology that has the location, scalp
Many morphologies have names that could be misinterpreted as implying a process rather than a structure.
Inflammation might mean the structural-morphologic features of inflammation, such as inflammatory cell infiltrates; or it might mean the process that causes the structural changes. Within the morphologic abnormality hierarchy, the structural interpretation is intended, not the process interpretation.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The morphologic abnormality subhierarchy is located two levels below the Body structure hierarchy with siblings Apoptosis and Structure resulting from tissue repair process:
SNOMED CT concept
Body structure (body structure)
Body structure, altered from its original anatomical structure (morphologic abnormality)
Apoptosis (morphologic abnormality)
Morphologically abnormal structure (morphologic abnormality)
The concepts in the morphologic abnormality hierarchy represent abnormal body structures.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
This section contains naming conventions for anatomical structures in SNOMED CT.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Distinguishing consistently between lump and mass can be difficult in diagnostic contexts, as the terms are often used interchangeably or lack precise definitions. As a result, lump and mass have, in certain conditions, been treated as synonymous.
Avoid using 'lump' in new content, where more specific terminology is available.
Lump should not be added as a synonym for mass concepts in the Finding or Disorder hierarchies. Existing legacy synonyms and concepts will remain unchanged.
Leave Primitive
The subhierarchy of 118956008 |Body structure, altered from its original anatomical structure (morphologic abnormality)| is to remain primitive. Authors are not to define morphologic abnormality concepts.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The genitourinary system includes the entire urinary system, as well as the genital system. The genital system includes internal genital organs and external genitalia.
The urinary system includes the organs that form and excrete urine, the kidneys, ureters, bladder, and urethra. The male urinary system includes the prostatic urethra (since it is a male urinary outflow structure).
In common usage, urinary system and urinary tract are used interchangeably. However, in SNOMED CT, this is not they case, i.e., they are not synonyms. The two concepts are: 122489005 |Urinary system structure (body structure)| and 431938005 |Structure of urinary tract proper (body structure)|.
The urinary tract proper includes the organs involved in the excretion of urine including the renal pelvis (but not the rest of the kidney), ureters, bladder, and urethra. It is used for disorders affecting the flow of urine (as opposed to its formation) or the urothelium, the lining of the urinary tract.
For example,
41368006 |Disorder of urinary tract proper (disorder)|
249273002 |Finding of urinary tract proper (finding)|
7163005 |Urinary tract obstruction (disorder)|
The upper urinary tract consists of the kidneys and the ureters (to the juncture with the bladder). Since upper urinary tract infections include kidney infection, the upper urinary tract must include the kidney.
The upper urinary tract proper is the part of the urinary tract proper. It includes only part of the kidney, the renal pelvis, and the ureters.
For example,
25990002 |Renal pelvis structure (body structure)| has a parent, 431491007 |Structure of upper urinary tract proper (body structure)|.
The lower urinary tract, 19787009 |Lower urinary tract structure (body structure)|, is the urinary system below the junction of the ureter with the bladder. It consists of the bladder and urethra. Lower urinary tract and lower urinary system are the same. The male and female specific components are located under male urinary outflow structure and female urinary outflow structure, respectively.
Obstetric and gravid body structures should not be added inSNOMED CT. Obstetric is a context for a disorder, procedure, or medical specialty that is applied to a body structure during pregnancy, childbirth, or the postpartum period. The context does not change the body structure.
The posterior lobe of the prostate is described in newborns but does not persist in the adult. 113295002 |Structure of lobe of prostate (body structure)| includes three lobes, left and right lateral, and medial.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
When considering the creation of a new morphological abnormality concept, consider the following:
When the name of a potentially new morphology is the same as the disease, creation of that new morphologic abnormality concept may not be beneficial since it would not be very morphologically descriptive.
Determine if there is benefit in creating a new morphology for a very small number of rarely used leaf nodes. If the new morphology is needed to differentiate two non-leaf concepts, that would be sufficient to create the new morphology. Otherwise, use the nearest existing morphologic abnormality.
Including a body site in a morphological abnormality concept is forbidden unless there is a clear modeling and pathological need.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
This is an example of a body structure that is used to group related terms.
The concept 707861009 |Structure of skin and/or skin-associated mucous membrane (body structure)| intentionally employs disjunction (inclusive Or). It includes structures in the deep layers, but excludes non-skin mucosal epithelium, e.g., bronchial, gastrointestinal, and genitourinary sites of squamous cell neoplasms. The 400199006 |Structure of skin and/or surface epithelium (body structure)| concept is used to represent the sites of these neoplasms.
Skin and/or skin-associated mucosa is intended for use in dermatology. It is not intended to subsume all mucosal structures, which are under Mucous membrane structure (body structure).
Since the phrase skin of finger can mean some or all of the skin of finger
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Many terms that refer to body systems or tracts are used imprecisely in clinical practice and in medical publications. Ambiguities frequently arise with many of these terms. We have made the following definitions and distinctions in order to achieve internal consistency of the terminology. We recognize that it may not be possible to get universal consensus for the names for each of these concepts. The goal is to be consistent and clear in defining the meaning of each concept and to allow users and system designers to present the terms that best reflect these meanings in their own implementations.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Both subchoroidal and suprachoroidal refer to the same potential anatomic space between the choroid and the sclera. The term lamina subchoroidea of choroid is the same as the lamina suprachoroidea.
There is not a vein actually named retinal vein. However, SNOMED CT has concepts with the phrase.
For example,
Formal definitions of scalp include layers beneath the skin. Therefore we make a distinction between 41695006 |Scalp structure (body structure)| and 43067004 |Skin structure of scalp (body structure)|.
There are at least three different use cases and meanings, and thus categories, for the phrase soft tissue. They include:
Tumors. Soft tissue gives rise to similar types of neoplasms of mesenchymal stem cell origin, generally called soft tissue neoplasms. This accounts for the inclusions/exclusions of the category. Non-neoplastic masses arising in soft tissue are included in the WHO Classification of Soft Tissue Tumours.
For tumors, soft tissue is defined as non-epithelial extraskeletal tissue of the body, exclusive of the mononuclear phagocyte system, glia, and supporting tissue of various mesenchymal organs. Other explicit inclusions are: fibrous tissue, fascia, ligaments, tendons, tendon sheaths, synovia, bursae, skeletal muscle, smooth muscle, fatty tissue, adipose tissue, blood vessels, lymph vessels, peripheral nerves, sympathetic and parasympathetic nerves, and ganglia, as well as subcutaneous tissue. Skin, skeletal cartilage, pleura, and the pericardium, peritoneum, central nervous system, endocrine glands, and viscera are excluded.
Sites of non-bone disorders and injuries of the limbs, head, neck, and body wall. Skeletal cartilage, as well as all non-bone structures of the limbs, and subcutaneous tissue and fat are included. Skin and lymph nodes are not included. For the head, neck and torso, mononuclear phagocyte system, central nervous system, endocrine glands, viscera, and supporting tissues are excluded.
Structures identified in images. Soft tissue include everything except for mineralized bone tissue and teeth.
Diseases of the skin
For the meaning of diseases of the skin , refer to the draft of ICD-11: Diseases of the skin incorporate conditions affecting the epidermis, its appendages (hair, hair follicle, sebaceous glands, apocrine sweat gland apparatus, eccrine sweat gland apparatus and nails) and associated mucous membranes (conjunctival, oral and genital), the dermis, the cutaneous vasculature and the subcutaneous tissue (subcutis).
Combined site (body structure)
The concepts under 116007004 | Combined site (body structure) | should not be used for concept modeling. They do not provide value for the classification of disorders or procedures. These concepts are ambiguous because their intended meaning is unclear, i.e., a combined site could represent any part of two or more sites or all of the referred sites in the description. The combined site (body structure) concepts will eventually be inactivated.
280927000 |Entire central vein of the retina (body structure)| has the synonym entire central retinal vein.
371398005 |Eye region structure (body structure)| has a synonym of orbital region structure which subsumes bony orbit, entire eye, and ocular adnexa.
In the literature, the term massive suprachoroidal hemorrhage is replacing expulsive hemorrhage and subchoroidal hemorrhage.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The nervous system has two parts, central and peripheral.
The central nervous system, sometimes also called the neuraxis , consists of the brain and spinal cord. The pyramidal system is a subdivision of the central nervous system; the extrapyramidal system is part of the brain.
The peripheral nervous system includes all neural structures outside the central nervous system.
The nervous system is also divided as: autonomic, somatic, and enteric.
The autonomic system is further divided as sympathetic and parasympathetic. The autonomic system is not entirely a part of the peripheral nervous system, but the autonomic nerves are peripheral.
The word nerve has multiple meanings according to the FMA:
nerve trunk
neural organ (trunk plus branches, excluding nuclei, ganglia, and roots)
neural tree organ, including nuclei, ganglia, roots, etc.
A neural tree organ is defined in FMA as a nonparenchymatous organ which has as its parts an aggregate of neurons (nuclei or ganglia) and their axons which are grouped into fasciculi by connective tissue to form elongated, cable-like structures that are arranged into a tree. A nerve , according to FMA, is defined as a segment of a neural tree organ which has as its parts a nerve trunk and its branches; together with other nerves of the same tree, it constitutes a neural tree. The neural tree structure includes:
Cranial nerve
Complex cranial nerve-tract
Spinal nerve
Nerve , conventionally has two meanings:
An anatomically distinct nerve trunk (without branches) that is identified in a dissection (e.g. the structure that student identifies when a pin is placed in the trunk of the vagus nerve, for instance located on the arch of the aorta)
A larger anatomical entity which supports a related set of functions (e.g. all anatomical components of the vagus nerve that are necessary for it to execute its functions (e.g. when a student is asked which nerve is responsible for slowing the heart the answer, the vagus nerve , includes the vagal nucleus, as well as the trunk and branches of the vagus).
Neural tree designates the second concept in order to distingiush it from the first which is only a part (subdivision of) the vagal neural tree.
A third meaning of nerve, defined by the FMA is: Segment of neural tree organ which has as its parts a nerve trunk and its branches; together with other nerves of the same tree it constitutes a neural tree.
For example,
Chorda tympani, digastric branch of facial nerve, greater petrosal nerve, posterior cutaneous branch of posterior ramus of cervical nerve, superior lateral cutaneous nerve of arm.
If one severs the facial nerve, the meaning refers to the trunk. But if one has facial nerve palsy, the meaning refers to the entire distribution of the nerve and the functions served by it.
Cerebrum may refer to the supratentorial brain, which is everything except the midbrain, medulla, pons, and cerebellum. In this interpretation, the telencephalon and diencephalon are in the cerebrum. On the other hand, cerebrum may only refer to the parts derived embryologically from the telencephalon, the cerebral hemispheres and the intercerebral commissure (corpus callosum and anterior commissure).
Supratentorial brain may be used for categorizing tumors and for designating the location of swelling that can result in herniation. The telencephalon and diencephalon (including thalamus, geniculate bodies, pineal body, habenulae, and hypothalamus) are definitely supratentorial. The upper part of the midbrain (mesencephalon) is also supratentorial. SNOMED CT excludes all midbrain structures from the supratentorial brain.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Fully specified names and preferred names should use proper names of digits of hand and foot. The names by order of digits can be added as optional synonyms. The order of fingers is different from the order of digits of hand because the thumb is not a finger in SNOMED CT. Therefore, the order of the finger should not be used to avoid potential confusion.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The terms 'spine' and 'vertebral column' in descriptions of conditions or procedures are often used loosely in clinical discourse but can relate to three different general anatomical concepts:
421060004 |Structure of vertebral column (body structure)| (synonym: Spinal column, ‘Backbone’, Spine)
includes the bones of the spine and associated joints and ligaments
289959001 |
Peripheral nerve
Autonomic nerve
There were several concepts with the phrase x nerve and its branches, interpreted as meaning _ the entire nerve and its branches._ Therefore, x nerve and its branches would be a duplicate of entire x nerve , when we interpret entire x nerve as being a neural tree organ.
For example,
Entire facial nerve is a neural tree organ, so there is no need for an additional concept called facial nerve and its branches.
Entire cranial nerve is a neural tree organ and structure of cranial nerve is that organ or any part (or branch) thereof. Branches of the cranial and spinal nerves are segments of the neural tree organs from which they branch.
All concepts named nerve x and its branches were inactivated due to their ambiguity. There are MAY BE A links to structure of nerve x , and entire nerve x. Specifying trunk of a nerve requires a specific concept.
Second digit of foot
Second toe
Third toe structure (body structure)
Third toe structure
Third digit of foot
Third toe
Fourth toe structure (body structure)
Fourth toe structure
Fourth digit of foot
Fourth toe
Little toe structure (body structure)
Little toe structure
Fifth digit of foot
Fifth toe
Index finger structure (body structure)
Index finger structure
Second digit of hand
Index finger
Little finger structure (body structure)
Little finger structure
Fifth digit of hand
Little finger
Middle finger structure (body structure)
Middle finger structure
Third digit of hand
Middle finger
Ring finger structure (body structure)
Ring finger structure
Fourth digit of hand
Ring finger
Thumb structure (body structure)
Thumb structure
First digit of hand
Thumb
Great toe structure (body structure)
Great toe structure
First digit of foot
First toe
Second toe structure (body structure)
Second toe structure
includes the vertebral column plus muscles and tendons associated with the spine
1141981001 |Structure of vertebral column region (body structure)|
includes the musculoskeletal structure of spine plus spinal canal, meninges, spinal cord, roots and ganglia and immediate soft tissue including adjacent vascular structures where specified.
The last concept has been allocated the following definition: This volume includes the spinal column, its spaces and contents, notably the spinal canal, spinal meninges and spinal cord. It also includes the muscles associated with the spine within (and including) the anterior and posterior thoracolumbar fascia and its equivalent nuchal fascia in the neck. This region also includes the spinal ventral (anterior) and dorsal (posterior) roots, the dorsal root (spinal) ganglions and the spinal nerve trunks.
To emphasize the different volumes, cross-sections are shown below of (Figure 1) the vertebral column in yellow, and (Figure 2) the larger vertebral column region in amber color.
From the preceding descriptions, it is clear that Vertebral column region is a broader concept for 'spine', and it should be used when a procedure or condition could involve not only the bony component of the vertebral column, but also the spinal cord, nerve root, muscle, bone, or joint of spine.
For example,
MRI of thoracic spine (procedure) is modeled with 1141986006 |Structure of thoracic vertebral column region (body structure)|.
Pain in sacrum (finding) is interpreted as being related to the more general notion of 1144746008 |Structure of sacral vertebral column region (body structure)|.
When a procedure or disorder is exclusively related to musculoskeletal structures of the spine, the 'musculoskeletal structure of spine' should be used.
For example,
Cervical traction (procedure), Manipulation of the cervical spine (procedure), and Rotational deformity of cervical spine (finding) are all modeled with 297166009 |Structure of musculoskeletal system of cervical spine (body structure)|.
Where a procedure or condition only effects the bone, joint, or ligament component (and not the muscles or tendons directly) the ‘vertebral column variant’ is used for modeling.
For example,
Benign neoplasm of lumbar vertebral column (disorder) and Kyphoplasty of fracture of lumbar spine using fluoroscopic guidance (procedure) are both modeled with 122496007 |Structure of lumbar vertebral column (body structure)|.
The sacrum is considered equivalent to the sacral vertebral column, as it is composed of the bone structure of the sacrum plus the joint structure of sacrococcygeal junction of spine.
The spine is traditionally divided into the following regions:
Cervical
Thoracic
Lumbar
Sacral
Coccyx
The anatomy of these individual segments are structured in accordance with the description above.
The regions and joints between these identified segments are referred to as cervicothoracic, thoracolumbar, lumbosacral and sacrococcygeal. The meaning of these words are subject in common parlance and some literature to be ambiguous.
For example,
‘Thoracolumbar’ sometimes refers to the thoracic spine and lumbar spine, or alternatively, it is used to express the junction between the thoracic spine and lumbar spine.
To avoid false assumptions, the junction of spinal segments in SNOMED CT have been made explicit by including the word junction in descriptions. This avoids potential misinterpretation as to whether a word such as ‘thoracolumbar' relates to both spinal segments or just the adjacent volume.
For example,
The notion of 1145014005 |Structure of thoracolumbar junction of vertebral column (body structure)| is only used for modeling when it is explicitly stated in the target concept e.g. 281907005 |Fracture dislocation of thoracolumbar junction (disorder)|.
By contrast, in the circumstance where a dependent concept relates to the combination of two segments, e.g. 702487007 |CT of thoracolumbar spine (procedure), (FSN Computed tomography of thoracic and lumbar spine), the concept is modeled with two axioms, namely Structure of lumbar vertebral column region and Structure of thoracic vertebral column region.
The volume or extent of the junctional zones themselves are not defined consistently in the literature but most commonly relate to the junction between two segments and one vertebra above and below. So the convention used in the SNOMED CT anatomy hierarchy follows this guidance.
For example,
1145014005 |Structure of thoracolumbar junction of vertebral column (body structure)| includes the following concepts in its class:
66794005 |Bone structure of L1 (body structure)|
23215003 |Bone structure of T12 (body structure)|
714833001 |Structure of intervertebral syndesmosis of T12 and L1 (body structure)|
181879009 |T12/L1 facet joint (body structure)|
In addition, a further convention is required as to where segmental junctional joints belong, i.e. either to the cephalic or caudal segment. For instance, does the T12/L1 facet joint relate to the Thoracic spine joint structure or/and Lumbar spine joint structure?
The convention used (based on common criteria of spinal injuries) is that the junctional joints are included with the cephalic segment. So, in the case of the T12/L1 facet joint, it is included in the class of Thoracic spine joint structure (body structure).
Similarly, 8454000 |Lumbar spine joint structure (body structure)| subsumes:
Intervertebral L5-S1 disc
Structure of lumbosacral joint
Structure of facet joint between L5 and S1
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Multiple x morphologies, such as 125291005 |Multiple cysts (morphologic abnormality)|, are currently subtypes of the “X” morphology. The “X” morphology concept represents a class rather than a singular instance, and this arrangement follows the open world assumption of the description logic in SNOMED CT.
For example,
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The ear includes the external, middle and inner ear. The external ear has two main parts, the auricle (also called the pinna) and the 84301002 |External auditory canal structure (body structure)|.
The external auditory canal has the synonym external auditory meatus. The external auditory meatus is not just the external opening of the canal, but rather the canal extending to the ear drum ( 42859004 |Tympanic membrane structure (body structure)|).
The 61671002 |Structure of internal acoustic meatus of temporal bone (body structure)| (SYN, internal auditory canal, is not part of the ear. As described in the FSN, it is an opening in the temporal bone, and is primarily a nerve conduit that anatomically parallel to the external auditory canal.
A similar example is how |Retinitis of bilateral eyes (disorder)| is a subconcept of |Retinitis of left eye (disorder)| and |Retinitis of right eye (disorder)|.
Having the Multiple X morphologic abnormality concept as a subtype of the “X” morphology concept allows the disorder concepts defined by these “multiple X” morphologies to be sufficiently defined. One drawback of the current format is that classification results are not complete.
For example,
Multiple cysts of eyelid would not subsume cysts of upper and lower eyelids in the current concept model.
In the future, these disorder concepts may be updated with a more robust representation utilizing cardinality as part of the logical definition. However, this functionality is not available in the reasoner profile of SNOMED CT at this time.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
There are a number of concepts in the anatomy hierarchy that represent congenital cardiac malformations. This content was developed in cooperation with IPCCC (International Pediatric and Congenital Cardiac Code).
The following pairs of cardiac valve concepts do not represent the same thing and are siblings, not super- or subtypes, to each other:
11124005 |Atrioventricular valve (body structure)| vs. 279316009 |Atrioventricular (non-mitral, non-tricuspid) valve structure (body structure)|
91134007 |Mitral valve structure (body structure)| vs. 312523009 |Left (non-mitral) atrioventricular valve structure (body structure)|
46030003 |Tricuspid valve structure (body structure)| vs. 244344000 |Entire right (non-tricuspid) atrioventricular valve (body structure)|
Atrioventricular (non-mitral, non-tricuspid) valves represent body structures which were anatomically abnormal from the beginning of their development. They are not called mitral/tricuspid valve although they perform the same function as their normal counterpart would. They are also represented using the term not morphologically mitral/tricuspid valve.
For example,
459176007 |Abscess of right atrioventricular (not morphologically tricuspid) valve (disorder)| represents an abscess of the right atrioventricular valve that has been developed abnormally from the beginning vs. 431189009 |Abscess of tricuspid valve (disorder)|.
For a normally developed mitral/tricuspid valve, the term left/right atrioventricular valve can be used interchangeably. They are true synonyms. However, they cannot be used for abnormally developed valves, i.e. left atrioventricular (non-mitral)/right atrioventricular (non-tricuspid) valves.
The systemic circulatory system is the combined arterial and venous circulation that begins where blood leaves the left ventricle and ends where blood enters the right atrium. It excludes the coronary circulation. The heart chambers are also considered part of the circulatory system.
The pulmonary circulation is the combined arterial and venous circulation that begins where blood leaves the right ventricle and ends where blood enters the left atrium.
Any artery of the pulmonary circulation, i.e. arteries carrying unoxygenated blood from the heart to the lungs. They include the trunk, right and left branches of the pulmonary artery (which are within the mediastinum), and all of their branches (which tend to occur at or past the hilum and are therefore regionally within the lung).
Any artery of the pulmonary circulation that is regionally within the lung, the boundary being defined by the hilum.
The main pulmonary artery (one of the great vessels that enter the heart) carrying blood from the right ventricle and dividing into right and left main pulmonary arteries (some dictionaries consider this synonymous with pulmonary artery).
There are four pulmonary veins that enter the left atrium, two on each side. These are what is intended by the name pulmonary vein (great vessels that enter the heart). In common usage, any vein that is part of the lung may be referred to as a pulmonary vein, but SNOMED CT has a separate concept: 122972007 |Pulmonary venous structure (body structure)|. This means any vein that drains the lung. A synonym is vein of lung. Pulmonary veins are veins of the lung, but pulmonary vein and vein of lung are not synonyms.
The term central vascular is not in common use. In fact, the term does not appear in SNOMED CT. However, the term peripheral vascular is very common, and therefore it requires a definition that (by default) sets the boundary between central and peripheral vascular systems.
The simplest definition of the peripheral vascular system is the vascular system that is not central; and then the central vascular system includes the pulmonary circulation, coronary circulation, cerebrovascular system, thoracic aorta, superior vena cava, inferior vena cava, and mediastinal blood vessels.
Peripheral vascular disease is often distinguished from cerebrovascular disease and coronary artery disease. These are the three major categories of diseases caused by problems in vascular circulation in general, and atherosclerosis, in particular. As a result of this clinical distinction, the cerebrovascular system is excluded from the peripheral vascular system.
Cerebrovascular is commonly defined in two ways: the blood vessels in the brain, or the blood vessels that supply the brain (including those within the brain). Because cerebrovascular disease includes extra-cranial occlusions of the vertebral and carotid arteries, we define the cerebrovascular system as those vessels involved in the supply and drainage of blood to the brain. Convention does, however, tend to exclude the innominate artery - which gives rise to the right common carotid and the arch of the aorta which gives rise to the left common carotid. Convention also excludes the subclavian arteries which give rise to the vertebral arteries.
The common carotid artery has a left and right component. The right common carotid artery has no thoracic portion (it arises from the brachiocephalic trunk behind the right sternoclavicular joint). The left common carotid artery has a thoracic portion (It arises from the arch of the aorta). Thus, the common carotid artery (not specifying laterality) is not exclusively an artery of the neck. This is because of the thoracic portion of the left common carotid artery. Then, artery of neck region includes the cervical part of left common carotid artery and all of the right common carotid artery.
Some vascular trees are located wholly within the cranial cavity, but some (internal carotid; vertebral) cross the boundary between extra- and intra-cranial. Intracranial segments of such vascular trees must be individually identified as such, and the entire vascular tree must not be categorized as either extra- or intra-cranial.
The word artery has three different meanings. In modeling SNOMED CT concepts that refer to arteries, it is necessary to decide on a case-by-case basis which of these meanings is intended.
The word vein has three different meanings. In modeling SNOMED CT concepts that refer to veins, it is necessary to decide on a case-by-case basis which of these meanings is intended.
Because trunks of veins, not venous trees, have been used to organize the vein hierarchy, there are implications for regional classes.
For example, the internal jugular vein is a vein of the neck, but its entire venous tree extends into the head. The internal jugular vein venous tree is not strictly part of the neck, even though the internal jugular vein venous trunk is strictly part of the neck.
Tributaries are also modeled as direct tributaries of the trunk. A tributary of a named vein is part of the venous tree of the named vein, but not part of the venous trunk of the named vein. Some veins that are part of the venous tree , and therefore might be regarded as indirect tributaries, are not modeled as direct tributaries of the trunk of the vein. Direct tributary is the intended meaning of tributary.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
When modeling a concept requiring two role groups with the same finding site/body structure but two different morphologies (because a combined morphology does not exist), then those two morphologic abnormalities can be combined to create a new single, combined |(morphologic abnormality)| concept. Keep the newly created morphologic abnormality concept primitive as all morphologic abnormality concepts should be primitive. Limit the combination to two morphological concepts into a single concept; combining more than two morphological concepts into a single combined concept is not permitted.
Example, If 400067002 |Acantholytic epidermal nevus (disorder)| had the same Finding site of |Skin structure (body structure)| with two different morphologic abnormalities of |Epidermal nevus (morphologic abnormality)| and |Acantholysis (morphologic abnormality)|, then those two morphologic abnormality concepts can be combined to create a single, primitive, morphologic abnormality concept of |Acantholytic epidermal nevus (morphologic abnormality)|. This will prevent modeling with two relationship groups.
Instead of modeling as per this diagram in the stated view with two morphologies of the same finding site:
Model as in the stated view of this diagram with a combined morphology:
Morphologies can be combined to create a single morphologic abnormality concept where doing so creates a specialization of the morphology e.g. 55075001 |Bleeding ulcer (morphologic abnormality)|. Where morphologies are different e.g. abscess and cellulitis, they can not be combined.
Combining morphologies to create a specialization is done when modeling a concept that requires two role groups with the same body structure and two morphology values. Creating a combined morphology concept enables one role group to be used.
Subtypes of 108369006 |Neoplasm (morphologic abnormality)| are not to be combined. These morphologies represent histological cell types that are recognized internationally by pathologists, classified by WHO, and aligned with the ICD-O classification.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Set of structures through which lymph flows. It includes 59441001 | Structure of lymph node (body structure) | and 83555006 | Structure of lymphatic vessel (body structure) |. It supports the categorization of findings, disorders and procedures that relate to the flow of lymph.
Set of structures with groups of lymphoid cells, including those in the intestines, marrow, liver, and other locations, and the lymph nodes, spleen, thymus, and tonsils and adenoids; excludes the lymph vessels. It supports categorization of lymphomas.
All of the lymphoid system, as well as the mononuclear phagocytic system; the immune system also includes cellular and sub-cellular components involved in cellular and humoral immunity.
Collection of true macrophages, distributed widely in the body (splenic and lymphoid sinusoids, liver Kuppfer cells, pulmonary alveolar macrophages, osteoclasts, macrophages in serous membranes, and microgliocytes); also endothelial cells that line hematopoietic tissues.
An arterial trunk, plus all its branches
When modeling, it is challenging to differentiate when trunk vs. trunk plus branches is intended.
NA
An arterial trunk: a single tube
The most common in clinical use.
The meaning of the word artery in injuries and operations is clearly a single tube, the trunk of the named artery, or trunk of the named arterial branch.
A puncture wound of the femoral artery affects the femoral arterial trunk.
A grafting into the popliteal artery is done into the popliteal arterial trunk.
Occlusions of arteries are located by naming the trunk where the occlusion occurs. Occlusions may affect circulation beyond the trunk, however, collateral circulation often mitigates the effects. Thus, it is incorrect to interpret artery to mean the entire subtree in any of these usages.
An arterial tree organ
There are only two complete arterial tree organs (the systemic arterial tree arising at the aortic valve, and the pulmonary arterial tree arising at the pulmonary valve) that are readily named as such. They are seldom referred to by disorders or procedures.
NA
A venous trunk
As with the clinical usage of the word artery , clinical usage of the word vein generally refers to the trunk and not the entire tree
A venous tree organ
There are only eleven venous tree organs that are readily named as such.
A venous trunk, plus all its branches
When modeling, it is challenging to differentiate when trunk vs. trunk plus branches is intended.
Nonexistent
There is no concept for Pulmonary vein within lung.
Tree-structured organs
See Tree-structured organs elsewhere, re: regional sections of venous and arterial tree organs.
Artery
This clinical usage of artery varies from the definition of the FMA, which defines artery as a subdivision of an arterial tree (organ) which consists of branching sets of tubes (arterial trunks) that form a tree; together with other arterial trees (organ parts), it constitutes an arterial tree (organ). The FMA definition corresponds to the third meaning of artery above.
Vein
This clinical usage of vein varies from the definition of the FMA, which defines vein as a subdivision of a venous tree (organ) which consists of branching sets of tubes (venous trunks) that form a tree; together with other venous trees (organ parts), it constitutes a venous tree (organ). The FMA definition corresponds to the third meaning of vein above.
Inactivation
All concepts with the name pattern vein x and its tributaries were inactivated due to ambiguity about their meanings. They have MAYBE A links to Structure of vein x and Entire vein x.
This guidance is not being applied retrospectively so the concept 707496003 |Inflammation and consolidation (morphologic abnormality)| will be an exception to this rule as it already exists as a current concept.
Older 'like' content may still use the two role groups. This content would also need to use the new combined morphology value to support correct subsumption.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The endocrine system is composed of the endocrine pancreas, pineal body, paraganglia, paraaortic bodies, parathyroid glands, endocrine ovaries, endocrine testes, adrenal glands, pituitary gland, thyroid gland, juxtaglomerular apparatus of the kidneys, and some diffuse neuroendocrine structures. Certain parts of the thymus produce endocrine hormones, but the thymus itself is not part of the endocrine system.
Bone marrow, the lymphoid system, the hematopoietic system, and the terminal cells of all lineages of the hematopoietic system (red cells, white cells, platelets, histiocytes, plasma cells, etc.). Disorders of the hematologic system do not necessarily include disorders of the hemostatic system, even though bleeding and thrombosis are usually categorized as hematologic.
Structures and cells responsible for erythropoiesis, granulocytopoiesis, monocytopoiesis, thrombocytopoiesis, and lymphopoiesis. Refers to the immature cellular elements that eventually form the cellular components of blood. The blood itself cannot be strictly part of the hematopoietic system, since this would cause all components of blood to be part of the hematopoietic system (including components like albumin, clearly not hematopoietic). SNOMED CT considers leukocytes, erythrocytes, and platelets the result of hematopoiesis, but not blood-forming, otherwise leukocytosis would become a disorder of hematopoiesis, whereas it can arise simply from a demargination of white cells following stress. SNOMED CT has a concept named 419333002 | Cellular component of blood (substance) |; note that platelets are not actually cells, but are cellular components.
The blood is not necessarily part of the cardiovascular system, nor is it necessarily part of the hematopoietic system. 87612001 |Blood (substance)| is a body fluid, not strictly part of either the hematopoietic or cardiovascular systems.
|Lymph node structure| could be a single node or multiple nodes. A term in single form does not mean it is a single anatomical entity. For example, | Inguinal lymph node structure | represents the lymph node(s) in the inguinal region. It is a representation of the type of anatomical entity. A 'Lymph node group' concept could have two distinctive concepts, e.g. lymph node of a particular classification group, or a group of nodes, representing the lymph node according to different groups in most cases. If it represents a group of nodes, the description should be in the plural form.
SNOMED CT has lymph node concepts per their anatomical locations, e.g. pulmonary, bronchopulmonary, tracheobronchial, tracheal, and esophageal) and concepts for node groups used for clinical staging of lung cancer, i.e., lymph nodes categorized into 14 stations.
Professional societies concerned with the clinical staging of lung cancer have developed at least three different nomenclatures for stations of lung-related lymph nodes. Even though the numbering of the stations is very similar, the inter-relationships between the various node groups are complex, particularly in stations 4 and 10, near the carina and hilar regions.
SNOMED International considers American Joint Committee on Cancer (AJCC) Station 10 , hilar lymph node, bronchial lymph node, and bronchopulmonary lymph node as synonyms. The American Thoracic Society (ATS) Station 10R, the right tracheobronchial lymph node is not a subtype of tracheobronchial lymph node because its definition includes nodes covered by both lower paratracheal lymph node,(AJCC Station 4) and by the hilar lymph node (AJCC Station 10). SNOMED CT uses tracheobronchial lymph node as a supertype of both inferior tracheobronchial (subcarinal) and superior tracheobronchial (a subset of lower paratracheal).
Modeling
Hematopoietic should be differentiated from hematologic , since the terminal cells of each lineage (the erythrocyte, segmented neutrophil, monocyte, histiocyte, platelet, mature T- and B-cells, plasma cells, etc.) are not strictly hematopoietic.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
For example,
Liver structure (body structure)
Entire liver (body structure)
Liver part (body structure)
For example,
For example,
S concepts are usually named x structure (body structure) or structure of x (body structure). E concepts are usually named entire x (body structure) or x entire (body structure). P concepts are usually named x part (body structure) or part of x (body structure).
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
There are two types of abscesses:
septic
sterile
Most abscesses are septic, which means that they are the result of an infection.
If a concept's meaning, based on its FSN and text definition, does not specify whether the abscess is sterile or septic, then the concept should not be modeled as septic.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Disorders which involve congenital anomalies are defined with:
Occurrence (attribute) = Congenital (qualifier value)
Associated morphology (attribute) = Morphologically abnormal structure (morphologic abnormality)
Pathological process (attribute) = Pathological development process (qualifier value)
Therefore, congenital does not need to be represented as the Associated morphology (attribute) target value. Congenital anomaly morphology concepts usually have non-congenital parents.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The skeletal system (systema skeletal in Nomina Anatomica) includes bones and cartilage. The bony skeleton includes bones only. The vertebral column is part of the skeletal system and includes the intervertebral discs (fibrocartilage). Individual vertebrae are part of the bony skeleton.
In ordinary usage, bone combines the meanings bone organ and bone tissue.
The 5 anatomical concepts related to bone are:
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
Fractures should be agnostic as to whether they are pathologic or not, unless specified in the FSN or could only be caused by trauma (e.g. open fractures). Although most fractures are traumatic, there are some pathological fractures. Based on its FSN and text definition, if the word pathological is present, use Pathologic fracture (morphologic abnormality).
21351003 |Fracture of phalanx of foot (disorder)|
Bone structure of phalanx of foot
Fracture (morphologic abnormality)
704168008 |Pathological fracture of phalanx of foot (disorder)|
Bone structure of phalanx of foot
Pathologic fracture (morphologic abnormality)
Modeling Abscess in Procedures
The concept's logical definition uses the Indirect morphology (attribute) of 44132006 |Abscess (morphologic abnormality)| and a Direct substance (attribute) of 11311000 |Pus (substance)|.
First digit of hand
Thumb
Entire liver (body structure)
Entire liver
Entire thumb (body structure)
Entire thumb
Entire first digit of hand
Liver structure (body structure)
Liver structure
Liver
Thumb structure (body structure)
Thumb structure
3138006 |Bone (tissue) structure (body structure)|. Tissue type that makes up bones; a quantity of regular connective tissue consisting of osteocytes and related cells, the intercellular matrix of which is ossified; or any part thereof.
90780006 |Entire bone (organ) (body structure)|. Individual bones, e.g., femur, tibia, ulna, scaphoid, lunate. An organ with cavitated parts; consists primarily of compact (cortical) and cancellous bone surrounding bone marrow cavities; also includes periosteum, endosteum (and, according to FMA, articular cartilage).
118966000 |Skeletal system subdivision (body structure)|. Groups of bones, e.g., spine, skull, bony pelvis.
128530007 |Entire bony skeleton (body structure)|. Pars ossea systematis skeletalis, bone part of the skeletal system.
113192009 |Skeletal system structure (body structure)|. Entire skeletal system, including bones and cartilage.
Bone (tissue) is part of entire bone (organ); entire bone (organ) is part of skeletal system subdivision (system); skeletal system subdivision (system) is part of entire bony skeleton (body structure); and entire bony skeleton (body structure) is part of skeletal system structure (body structure). We can use Entire bone (system) to define aggregate concepts that involve bones.
Bone organs are composed primarily of bone tissue, but there are some non-ossified parts. In particular, periosteum is clearly a part of a bone organ, but is not ossified tissue.
Bone marrow is contained within the marrow cavity, but it is not part of the bone organ. The (empty) marrow cavity is part of the bone organ. The bone marrow structure (body structure) is not a subtype of Bone structure (body structure).
Clinically, marrow disorders are not usually considered bone disorders, nor are marrow procedures considered bone procedures.
For example,
Bone marrow disorders are not musculoskeletal disorders, but bone disorders are musculoskeletal disorders. Bone marrow transplants are not considered types of bone transplant.
60168000 |Osteomyelitis (disorder)| is not the same as 44462005 |Osteitis (disorder)|.
To differentiate marrow, vessels, nerves, and periosteum from the actual hard tissue of bones, we differentiate structure of tibia from 12611008 |Bone structure of tibia (body structure)|. The bone marrow and other soft tissues of the tibia can then be categorized separately from the hard tissues. Bone marrow diseases are not considered musculoskeletal diseases, so bone marrow structures should not be placed in the bone (tissue) structure hierarchy.
ICD does not use the standard anatomical definition of long bone. For instance, Benign neoplasms of long bones are distinguished from benign neoplasms of short bones ; the bones of the hand are considered short bones. The anatomical definition of long bone cites the proportional relationship between length and width (length >> width). It is clear that metacarpals, metatarsals, and phalanges are included in the anatomical definition of long bone.
In order to accommodate the differences between anatomical definitions and classifications, SNOMED CT has anatomical groupings that correspond to the ICD groupings. Scapula, humerus, radius, or ulna, and long bone of thigh or lower leg are used as the sites for grouper concepts that match ICD definitions and groupings.
The sternum is considered a bone organ. The manubrium, body, and xiphoid are parts of the sternum, classed as zones in the FMA.
Even though teeth are supported by the maxillary or mandibular bone, they are not part of the 70925003 |Bone structure of maxilla (body structure)| or 91609006 |Bone structure of mandible (body structure)|. Teeth are part of the 4335006 |Upper jaw region structure (body structure)| and 48077000 |Lower jaw region structure (body structure)|.
In many diseases and procedures, reference is made to areas of the body that may ambiguously imply either a joint or a region surrounding the joint. Some common ones are:
70258002 | Ankle joint structure (body structure) |
344001 | Ankle region structure (body structure) |
74670003 | Wrist joint structure (body structure) |
8205005 | Wrist region structure (body structure) |
85537004 | Glenohumeral joint structure (body structure) |
16982005 | Shoulder region structure (body structure) |
272691005 | Bone structure of shoulder girdle (body structure)| This concept is used to define diseases and procedures affecting bones in the shoulder region, i.e. proximal humerus, scapula, and clavicle. It is not a bone, but a bone structure, and is part of the shoulder region.
27949001 |Intertarsal joint structure (body structure)|; SYN: Tarsal joint: This structure is part of a group of bones forming the tarsus or tarsal joint (ankle). The 27162001 |Talocalcaneonavicular joint structure (body structure)| is the articulation between the talus (one of the seven bones of the ankle joint) and the other bones of the tarsus, and is what is meant by the rarely-used term talotarsal joint. The talocalcaneal joint is a synonym for the 127863007 |Subtalar joint structure (body structure)|. Dislocations of the subtalar joint usually involve the 127864001 |Structure of talonavicular joint (body structure)|. The subtalar and talonavicular joints constitute the talocalcaneonavicular joint.
The meaning of the words arm and leg may be misinterpreted.
Arm may refer to the upper limb, but it may also refer to the upper part of the arm.
Leg may refer to the lower limb, but it may also refer to the lower part of the leg.
In common usage, leg is a synonym of lower extremity, and arm is a synonym of upper extremity.
In SNOMED CT,
53120007 |Upper limb structure (body structure)| includes the shoulder, upper arm, forearm, wrist, and hand
Upper arm is a synonym to 40983000 |Structure of upper extremity between shoulder and elbow (body structure)|.
61685007 |Lower limb structure (body structure)| includes the hip, thigh, lower leg, ankle and foot.
Lower leg is a synonym to 30021000 |Structure of lower extremity from knee to ankle (body structure)|. Lower leg does not include the foot. Stedman's Medical Terminology defines lower leg as the segment of the inferior limb between the knee and the ankle.
The word limb appears in the FSN of the body structure, while the word extremity appears as a synonym. Therefore, when constructing an FSN for a new clinical finding concept, this precedent should be followed:
FSN: 61685007 |Lower limb structure (body structure)|
PT: Lower limb structure
Synonym: Lower extremity
Additional descriptions of leg and arm are permitted for concepts whose FSNs refer to lower limb and upper limb respectively.
The shoulder region is part of the upper limb, and the hip region is part of the lower limb. This follows the general pattern used in the Foundation Model of Anatomy (FMA).
The FMA defines:
upper limb as the free upper limb and the pectoral girdle (of which the shoulder region is part). SNOMED CT has the concept 896766000 |Structure of free upper limb (body structure)|.
lower limb as the free lower limb and pelvic girdle (of which the hip region is part). SNOMED CT has the concept 699617006 |Structure of free lower limb (body structure)|, i.e. the lower limb not including the pelvic girdle.
The axilla is bound by the upper limb laterally and the thorax medially. It may be viewed as not strictly part of the upper limb or the thorax or it may be views as part of both. 91470000 |Axillary region structure (body structure)| is defined in SNOMED CT as being both an upper limb structure and a thoracic structure.
A muscle may be considered an entire functional unit, including attachments to the skeletal system, or merely the contractile part of this unit. In clinical use, muscle is the contractile part only. The FMA definition implies that tendons should be considered part of their corresponding muscles, rather than organs in their own right. SNOMED CT models |Tendon structure| as a subtype of |Skeletal muscle and/or tendon structure (body structure)|. Muscle and tendon are two separate anatomical entities.
For example,
61352006 |Structure of achilles tendon (body structure)| is not a 53451005 |Triceps surae muscle structure (body structure)| (gastrocnemius and/or soleus) muscle structure.
When modeling muscle categories according to their functions, assume they mean the function of the entire muscle, unless stated otherwise.
Skeletal system subdivision
SNOMED CT considers the skeletal system subdivision part of the entire bone (system). This may change if there are procedures on cartilaginous skeleton that involve skeletal system subdivisions.
Modeling
FSNs for spinal levels should not contain abbreviations.
Correct example,
Modeling: phalanx (finger)
The index finger is the first finger and second digit. Do not use second finger.
External sources
External sources, such as WHO Classifications, may have conventions for interpreting the meaning of phrases that contain the words arm and leg. These sources may be referenced to help determine the meanings of International Classification of Diseases (ICD) terms when mapping or completing other actions. ICD terms may differ from common usage and will not necessarily match SNOMED CT concepts.
Unacceptable terms
X disorder at Y level concepts from ICD-11, e.g., skin laceration of arm at wrist level (precedent are terms added from ICD-9) will not be added to the SNOMED International Release.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
SNOMED CT uses the Foundation Model of Anatomy (FMA) definition of body part and body part subdivision for some concepts. For example, the joint regions discussed below are classified as body part subdivisions, since that is what is intended by the diseases and procedures that use these terms in their definitions. They are not body parts because they are defined, not by a set of bones, but rather by a particular joint and its surrounding structures. However, our interpretation of the word region is based on common usage and is intended as a three-dimensional structure, not the FMA two-dimensional definition of body region. In other words, these regions are not simply surface regions (skin), but also include the three dimensional underlying structures (subcutaneous tissues, bones, muscles, tendons, fascia, vessels and etc.).
Many concepts contain the phrase surface region. These could be interpreted as massless (immaterial) mathematical surfaces, but a clinical terminology would have no direct use for such meanings in clinical records. They could be interpreted as having mass (not immaterial), but the depth then is arbitrary. Should it be just skin deep, or should it include deeper layers of the surface? If only skin deep, the meaning of these concepts would overlap with concepts for skin regions. If deeper, the meaning would possibly be the same as the generic structure concepts.
The named regions of the abdomen are by tradition divided horizontally by the transpyloric plane and the interspinous plane, and vertically by the midclavicular plane. The lateral regions are therefore bounded above by a plane that is inferior to the ribs. In contrast, the flank is the lateral region of the abdomen bounded above by the ribs. Thus some parts of the hypochondriac regions, which are superior to the transpyloric plane but inferior to the ribs, would be considered also part of the flank. The hypogastric region is also sometimes called the pubic region.
The term abdominal cavity has two meanings, one including the pelvic cavity , the other excluding it. Abdominal cavity structure includes both. Abdominal cavity proper excludes the pelvic cavity.
The FMA definition of body organ is also used. Organs include individual bones, joints, muscles, arteries, veins, lymph vessels, nerves, and etc. Concepts that include groups of organs are frequently used in SNOMED CT. In most cases, these have been part of the subsumption hierarchy (IS A hierarchy) of the particular organ type, that is, they are kinds of organs.
For concepts that refer to the collection of organs (rather than organs in a collection), there is another concept that is a, kind of, organ system subdivision. Many such collections do not yet have corresponding organ system subdivision concepts. The default is to interpret concepts as denoting organs, rather than organ system subdivisions.
In general, organs are made up of tissue, and tissue is made up of cells. However, a cell is not necessarily part of tissue, and tissue is not necessarily part of a named organ.
Arteries, veins, nerves, and the bronchi form tree-like structures that distribute across multiple regions. Because of their size and links with other structures, they require slightly different modeling. FMA divides tree structured organs as: organs with organ cavities and organs that are solid.
Organ with organ cavity has a subtype, hollow tree organ. The hollow tree organs are:
Tracheobronchial
Biliary
Vascular
Among the solid organs, there is one category, neural , that is tree-structured (see: Nervous system; neural tree).
Male and female are unnecessary descriptions in describing the breast. Gender information should be obtained and recorded separately in the information model. New content that requests male or female breast will not be accepted so as not to duplicate gender-specific anatomical concepts.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The 123037004 |Body structure (body structure)| subhierarchy includes both anatomical structures and morphologic abnormalities
Body structure
The body structure domain includes anatomical structures, as well as morphologic abnormalities, as follows:
Body structure (body structure)
Anatomical or acquired body structure (body structure)
Anatomical organizational pattern (body structure)
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
321667001 |Respiratory tract structure (body structure)|. In SNOMED CT, respiratory tract has the same meaning as the Nomina Anatomica term apparatus respiratorius , which includes the structures through which air passes from the nares to the alveoli. The oral cavity is not included. In common usage, respiratory system may have the same meaning as respiratory tract ; but not in SNOMED CT. Respiratory system does not mean the global respiratory system that might include the CNS components of breathing. Pleura are part of the lower respiratory system, but not a part of the lower respiratory tract.
This phrase has several meanings. The SNOMED CT concepts 119253004 |Upper aerodigestive tract structure (body structure)| and 361922007 |Entire upper aerodigestive tract (body structure)| have the meaning based on the following reference: Cancers of the upper aerodigestive tract constitute approximately 4% of all malignancies. These include cancer of the lip, tongue, major salivary glands, gums and adjacent oral cavity tissues, floor of the mouth, tonsils, oropharynx, nasopharynx, hypopharynx and other oral regions, nasal cavity, accessory sinuses, middle ear, and larynx (Upper aerodigestive tract cancers, Cancer 1995 Jan 1;75 (1 Suppl): 147-53). This definition matches the tumors included in the CAP Cancer Checklist for upper aerodigestive tumors. The esophagus, or at least the cervical esophagus, may be included, but not in SNOMED CT .
58675001 |Upper respiratory tract structure (body structure)| includes the nasal cavity, paranasal sinuses, nasopharynx, oropharynx, and larynx
82094008 |Lower respiratory tract structure (body structure)| includes the tracheobronchial tree (from the trachea through the terminal bronchioles) and the lungs, including the alveolar respiratory tract (which extends from the respiratory bronchioles to the alveoli).
400141005 |Lower respiratory system structure (body structure)| includes the lower respiratory tract and the pleura.
The interarytenoid fold forms part of the inlet of the larynx. The fold has two surfaces, one forming part of the wall of the supraglottic larynx, the other forming part of the wall of the hypopharynx (the food tube behind the larynx, leading to the esophagus). The 102295003 |Structure of hypopharyngeal aspect of interarytenoid fold (body structure)| may be considered part of the hypopharynx, the larynx, or both. A tumor of this site is categorized as a tumor of the hypopharynx, and not the larynx, but the 105585004 |Interarytenoid fold structure (body structure)| is considered part of the larynx.
SNOMED CT does not give a Part of relationship between the hypopharyngeal aspect of the interarytenoid fold and the interarytenoid fold. This emphasizes SNOMED CT modeling based on the relationship of anatomical entities and disorders and procedures and not simply by reading term names.
SNOMED CT differentiates between the bone underlying the nasal turbinates and the actual turbinates:
Bones underlying the turbinates,
118648008 |Inferior nasal turbinate bone structure (body structure)|
122491002 |Middle nasal turbinate bone structure (body structure)|
122492009 |Superior nasal turbinate bone structure (body structure)|
Turbinates, which include bone, overlying mucous membranes, and other tissue,
6553002 |Inferior nasal turbinate structure (body structure)|
122491002 |Middle nasal turbinate bone structure (body structure)|
65289004 |Superior nasal turbinate structure (body structure)|
The 118648008 |Inferior nasal turbinate bone structure (body structure)| is a facial bone and skull bone. And, parts of the ethmoid bone form the middle, superior, and supreme nasal conchae. This means that the bones of the middle, superior, and supreme turbinates are not bone organs.
Posterior cord syndrome at tenth thoracic spinal cord level, not Posterior cord syndrome of thoracic spinal cord at T10 level
Bone of skull
Skull (subdivision of skeletal system)
Bone of thoracic cage
Thoracic cage (subdivision of skeletal system)
Rib
No corresponding organ system subdivision concept
Third rib
No corresponding organ system subdivision concept
Right third rib
No corresponding organ system subdivision concept
Quadriceps femoris muscle
No corresponding organ system subdivision concept
Quadriceps femoris muscle, left
No corresponding organ system subdivision concept
Vastus medialis muscle
No corresponding organ system subdivision concept
Systemic arterial
Pulmonary arterial
Venous
Systemic venous (superior, inferior, and 4 cardiac trees)
Pulmonary venous (superior and inferior left and superior and inferior right)
Portal venous
Lymphatic (right lymphatic duct and thoracic duct)
Vertebra (bone of vertebral column)
Spine (subdivision of skeletal system)
Cervical vertebra
Cervical spine (subdivision of spine)
Third cervical vertebra
No corresponding organ system subdivision concept
Inactivation
Most surface region concepts will be retired as ambiguous/_possibly equivalent to _their corresponding concepts that are clearly not immaterial, including x structure, entire x, and skin of X. Where the x structure codes do not currently exist, they will be created, without the surface region phrase.
Unacceptable terms
X disorder at Y level concepts originating from ICD-11, e.g., Skin laceration of arm at wrist level (precedent are terms added from ICD-9) are not added to the SNOMED International Release.
Laterality
For information on laterality, see Anatomical Structure Naming Conventions section at Naming Convention for Digits of Hand and Foot and Laterality section at Laterality
Body structure, altered from its original anatomical structure (morphologic abnormality)
Nonspecific site (body structure)
Normal anatomy (body structure)
Topography not assigned (body structure)
Topography unknown (body structure)
38033009 | Amputation stump (body structure) |
91134007 | Mitral valve structure (body structure) |
Morphologic abnormality
189955008 | Biopsy wound (morphologic abnormality) |
31470003 | Adenosarcoma (morphologic abnormality) |
Cell
250293008 | Agranular white blood cell (cell) |
57184004 | T lymphocyte (cell) |
Cell structure
4897009 | Cell membrane, prokaryotic (cell structure) |
362293000 | Entire axon (cell structure) |
Tumor staging
Concepts under 258331007 | Anatomical site notations for tumor staging (body structure) | require review and reallocation.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
The anatomy structures should only be pre-coordinated with laterality if they are lateralizable. All anatomy structures on the midline are not lateralizable. The Lateralizable Body Structure Reference Set has been developed and published as part of SNOMED International release. Please note that the refset requires an ongoing update for new additions.
Both Left and Right structures must be added when adding the new pre-coordinated concepts for anatomy structure with laterality. Lateralization should not be routinely applied to Entire and Part of anatomy concepts unless the concept model requires such lateralized anatomy structure.
Bilateral X anatomical structure (body structure) must not be added. The concepts under 422525002 |Structure of bilateral paired structures (body structure)| are no longer in use in the international edition of SNOMED CT because bilateral concepts are defined by two role groups. However, these concepts may still be in use by extensions, in post-coordinations, or as values in information models. We would recommend users to review their usage and provide feedback to us. Users will be consulted before these concepts are ultimately inactivated.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
When authoring in this domain, these are the approved attributes and allowable ranges.
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
SNOMED CT uses a structure-entire-part triple, known as the SEP triple , to represent anatomical structures. The following Relationships provided a way for the anatomy in CTV3 to be mapped to RT:
The SNOMED CT anatomy hierarchy differentiates classes of entire anatomical entities from classes of parts of entire anatomical entities.
Entire concept : Denotes a class that is instantiated by entire anatomical entities of some kind: entire heart is instantiated by all individual hearts.
Entity P
Entity Structure concept : Subsumes both the related Entire and Part concepts. Consequently, it denotes a class which is instantiated by anything that instantiates either the Entire or the Part. For instance, Heart structure is instantiated by my heart, my mitral valve, your heart, your right ventricle, Joe's sinus node, Joe's heart, etc.
The code named Liver structure in CTV3 is equivalent to Liver structure in the diagram above. Both the CTV3 code for Liver structure and the SNOMED RT code for Liver are interpreted to mean Some or all of the liver. Site attributes (PROCEDURE SITE, FINDING SITE) will usually take the value liver structure rather than entire liver , since typically the site of a liver disorder or procedure on the liver is not necessarily the entire liver.
Adding the Entity Structure codes is a convenience to assist with the logic-based aggregation of references to the entity or its parts. The implication of this view is that the E of the SEP triple is the code that should be regarded as the one that represents the real anatomical entity that is named.
For example, the code for entire liver is the one that should correspond to the code for liver in the Foundational Model of Anatomy (FMA). The subtype hierarchy __ for entire liver fits much better with the FMA hierarchies, and indeed it might be possible to completely reconcile SNOMED’s non-Structure components with FMA anatomy.
A database has been developed that categorizes codes in the physical anatomical entity hierarchy according to their status as S structure, P Part or E Entire, and provides the corresponding S and P code for each E code. This should provide some value to implementers. It can help with navigation, coordination with formal ontologies of anatomy, and selection of codes for postcoordination.
Where there were two concepts with the same name, the SNOMED RT code was to become the S code, and the CTV3 code was to become the E code. There are still instances of unrecognized pairing of the RT-CTV3 S-E pair, where neither codes FSN has been changed according to the naming conventions in this document. When these unmatched pairs are identified, it is our practice to change the FSNs accordingly, and to make the E code have a subtype IS-A link to the S code.
Some S codes do not currently have a corresponding E code subtype, and there was no policy that required that such E codes be created during the merger of SNOMED RT and CTV3. However, it is likely that such a policy will be enforced in the future.
The SEP triple may give the impression that all S codes have exactly two children, one E and one P , with all of the remaining descendants placed under P. Again, in the past this degree of modeling consistency was not always followed. Some codes were purposely made subtypes of the S that are not strictly part of the corresponding E.
For example, perirenal tissue is a kidney structure but not a part of the kidney. It is used to define perirenal abscess so that it is subsumed by renal abscess. While a perirenal abscess is not strictly within the substance of the kidney, it is still considered a kind of renal abscess, and the S anatomy hierarchy is used to support this inference.
This policy has introduced undesirable variation and arbitrariness into the terminology, and future revisions will seek to eliminate these variations. Where a code is needed for a site that is really meant to extend to entities that are not part of any kidney, this will be made clear in the name, e.g. Structure of kidney and perirenal tissue.
The E code needs to be interpreted with care when the x name refers to entities that do not have the property of identity, meaning that they are not countable wholes, or could be interpreted as non-countable. In this circumstance, the interpretation of E means some portion of the thing being named.
For example, tissue and types of tissue such as fascia, muscle, tendon, bone tissue, connective tissue, skin, mucosa/mucous membrane, nerve tissue, etc. Muscle, tendon, bone and skin can identify a type of tissue as well as an individual organ of that type. Bone tissue has no identity, but a particular bone does have identity.
To use skin as the archetypal example, the E code for skin of finger means a portion of the skin of a finger, so all of its subtypes must also be portions of skin. The S code for skin of finger then has a subtype P which would mean proper part of a portion of skin of finger. This admits subtypes that are not kinds of skin, but may be parts of skin, including layers, e.g. epidermis of finger (meaning a portion of epidermis of finger) could be a proper part of a portion of skin of finger.
We regard the E code for x tissue, x layer to have the meaning portion of X tissue , and therefore regional subdivisions of tissue types are direct subtypes.
For example, transitional epithelium of urinary tract, as an E kind of code, should be a supertype of transitional epithelium of urinary bladder. The reason is that (portion of) transitional epithelium of urinary bladder is a kind of (portion of) transitional epithelium of urinary tract.
We also deal with layers the same way.
For example, we regard serosal layer and serosa tissue as meaning the same thing, since all serosal tissue is conifigured as a layer, and it can’t be a serosa without being a layer; and their E codes mean portion of serosal layer or portion of serosal tissue.
As another example, layer of retina would be a supertype of nerve fiber layer of retina, and also a supertype of retinal epithelium, where retinal epithelium represents a portion of the epithelium of the retina and is therefore a kind of (portion of) a layer.
The identity/countability issue extends to a problem differentiating groups of entities from one of the group.
For example, consider x = lymph node group , y = lymph node. In this case, the group should be linked to the member via an appropriate Relationship(not yet in SNOMED CT), such as has-member. In those cases where y is always necessarily a member of group x, it could be linked via a member-of Relationship(also not yet in SNOMED CT).
What does part of mean?
There are several possible ways of interpreting part of. In SNOMED CT, A part of B means that in normal anatomy, the entire structure A is structurally included in B. Another way of saying it is that A is part of B if there is no part of A that is not also part of B.
For example, the humerus is not part of the shoulder region, because the distal humerus is part of the humerus, and the distal humerus is not part of the shoulder region.
We do not use part of for non-anatomical meanings, such as grouping tests together in batteries, nor do we use it to indicate Relationships that are not strict anatomical inclusion.
Some recent work has begun to differentiate between part of that is reflexive (that is, an entity is in some sense a part of itself , much the same that a set can be viewed as a subset of itself), versus proper part of , where an entity cannot be a proper part of itself. For now, we regard part of Relationships as implying strict partonomy.
There is sometimes confusion about parthood as opposed to location.
For example, an embryo is not part of a mother's body, but a kidney is. The anatomy section is composed mainly of canonical parts; but a few abnormal parts are included to permit them to be used as the location of tumors or injuries.
For example, a Meckels diverticulum is a body structure that is part of the small intestine, and it is also a morphological abnormality. Likewise some stomas and other post-surgical structures are considered part of the body. A transplanted liver or kidney would be considered part of the body, as a post-surgical structure, even though the transplanted organ is not genetically identical. Likewise transplanted bone marrow is part of the body.
Non-living implants and devices, and foreign bodies, on the other hand, are considered to be located in the body, but not part of the body.
For more information on part of relationships in the anatomy concept model, please see Part of relationships (under development).
The currently distributed part of Relationships need to be much more extensively modeled and quality assured. At present they are not defining , that is, their Characteristic Type in the relationship file is additional, and, therefore, they do not affect the classifier behavior. A substantial amount of effort has gone into a draft of the updated part of Relationships; these will require review and approval before incorporation into the release. This will eventually result in the SEP triplet structures and part of relations being strictly paralleled. It is a matter of time to implement and quality assure the changes.
The SEP structure, combined with the inference mechanism that is used with SNOMED CT, allows us to take advantage of anatomical Relationships to infer subsumption, IS_A Relationships between disorders, procedures, and other entities without reference to part of Relationships. The SEP structure also permits us to sufficiently define anatomical structures without reference to part of Relationships (making them necessarily true , but not among the necessary and sufficient conditions).
For example, the Structure of left hand can be sufficiently defined as a hand structure with laterality = left. This definition is sufficient. Converting the part of Relationships to have Characteristic Status = defining will require significant changes to the current model.
Points, lines, and surfaces can be considered to be massless. The FMA calls these immaterial. It is important to differentiate the codes/names for these entities from those that are intended to represent entities that have mass. At present, the concepts under anatomical spatial entity represent massless entities. Massless entities are not represented using the SEP model. It is conceivable that users may want to reference parts of a surface, and to enable this we would need to apply the SEP model to anatomical spatial entities, or else adopt defining part of Relationships.
This attribute provides information on whether a body structure is left, right, or bilateral. It is applied only to bilaterally symmetrical body structures which exist on opposite sides of the body.
With the addition of lateralized content in the International Release, the need for unspecified unilateral concepts is removed, as well as potentially dangerous, if used directly in a patient record. Unilateral concepts will not be accepted.
Following are the most common term patterns for the representation of laterality for anatomy structures. Preferred terms should have the same description without a semantic tag. In descriptions in hierarchies such as clinical finding/disorder, procedure, observable entity, and situation with explicit context, 'structure of' can be omitted when body site is not a concept of Entire anatomy entity.
Structure of left hand (body structure)
Structure of right lung (body structure)
Structure of left ring finger (body structure)
Structure of left renal artery (body structure)
Bone structure of left tibia (body structure)
Structure of right half of head (body structure)
Structure of right cerebral hemisphere (body structure)
Bone structure of left hand (body structure) - bone structure is constitutional part of hand
Bone structure of phalanx of left ring finger (body structure)
Skin structure of right foot (body structure) - skin structure is constitutional part of foot
Skin structure of left index finger (body structure)
Bone structure of proximal right humerus (body structure) - proximal is regional part of humerus
Bone structure of shaft of left femur (body structure) - shaft is regional part of femur
Finger/toe is not sufficient - Laterality should be placed before hand/foot when finger/toe or any part of a finger/toe is not further specified to individual digit, e.g., ring finger, index finger, great toe.
Structure of finger of left hand (body structure)
🟢 correct
Structure of left finger (body structure)
🔴 incorrect
Bone structure of phalanx of finger of left hand (body structure)
🟢 correct
Parts of symmetric structures should be symmetric. However, some body parts are exceptions. The laterality value in modeling is inherited from its lateralizable parent concept, e.g. left/right lung structure. Therefore, descriptions must clearly indicate such inheritances to avoid potential confusion. It is not accurate for a term such as "right middle lobe" because there is no "left middle lobe". The following are examples for correct description pattern. Note: existing content has not been following the term pattern.
Leave the new concept as primitive if concept 'Structure of half of Y lateral to mid-sagittal plane (body structure)' does not exist. The new concept for 'Structure of half of Y lateral to midsagittal plane' should not be added until the policy is developed.
The 'part of' relationship should not be used for concept modeling in anatomy. The laterality attribute should be the only attribute for the representation of laterality. The new concept model for anatomy has not been implemented, and the proximal primitive modeling style should not be applied.
For term pattern 1, the concept X or lateral half of Y should be used to fully define a concept with laterality, as shown in these examples:
For term pattern 2, the pre-coordinated concept {part} of X should be used to fully define the concept with laterality. Note: Concepts for which an identifier has not been assigned have been shown with an identifier of '1111111111'.
For example,
Please note that the concept modeling and utility of pre-coordinated concepts of 'structure of {part} of lateral half of Y' and 'structure of half of Y lateral to mid-sagittal plane' are still under investigation. Similar new anatomy concepts should not be added. The concept model should only use existing pre-coordinated concept {part} of lateral half of Y.
For example,
If pre-coordinated concept does not exist for '{part} of structure of half of Y' or 'structure of half of Y lateral to mid-sagittal plane', the concept can be defined by {part} of Y and the definition status should be primitive.
For example, concept |Structure of lateral half of lower back| does not exist, the concept 'Structure of left half of lower back' should be defined as a primitive concept. Two parent concepts are expected: 61379005 |Structure of left side of trunk (body structure)| and 37822005 |Lower back structure (body structure)|. The additional parent |Structure of left side of trunk (body structure)| is to ensure that any lateralized concept must be a subconcept of a lateralizable structure.
In this guide, the lateralizable anatomy structures are divided into three types:
X
The type X represents any anatomy structure that is lateral to mid-sagittal plane.
Lateral half of Y
Y represents any anatomy structure that is symmetrical on the body's middle-line which cannot be lateralized. However, the lateral half of Y can have laterality, e.g. right half of head.
{Part} of X or Y
{Part} represents any constitutional or regional part of anatomical structure of X or lateral half of Y.
See also the policy for a preferred term in relationship to Structure vs. Entire at .
Parent Domain
-
Proximal Primitive Constraint
<< 123037004 | Body structure (body structure) |
Proximal Primitive Refinement
-
733928003 | All or part of (attribute) |
0
0..*
0..0
Domain Constraint
<< 91723000 | Anatomical structure (body structure) |
Parent Domain
123037004 | Body structure (body structure) |
Proximal Primitive Constraint
<< 91723000 | Anatomical structure (body structure) |
272741003 | Laterality (attribute) |
0
0..1
0..0
For all Anatomical structure (body structure) concepts, Laterality is an approved attribute which can be populated with the range of qualifier values including Side (qualifier value) or its subtypes.
Domain Constraint
<< 123037004 | Body structure (body structure) |
<< 123037004 | Body structure (body structure) |
733931002 | Constitutional part of (attribute) |
0
0..*
0..0
<< 123037004 | Body structure (body structure) |
1230370004 | Is vasculature of (attribute) |
0
0..*
0..0
<< 123037004 | Body structure (body structure) |
733933004 | Lateral half of (attribute) |
0
0..*
0..0
<< 123037004 | Body structure (body structure) |
774081006 | Proper part of (attribute) |
0
0..*
0..0
<< 123037004 | Body structure (body structure) |
733930001 | Regional part of (attribute) |
0
0..*
0..0
<< 123037004 | Body structure (body structure) |
733932009 | Systemic part of (attribute) |
0
0..*
0..0
<< 123037004 | Body structure (body structure) |
Proximal Primitive Refinement
-
<< 182353008 | Side (qualifier value) |
Bone structure of phalanx of left finger (body structure)
🔴 incorrect
Structure of nail of toe of right foot (body structure)
🔴 incorrect , neither 'right nail' nor 'right toe' is correct
Note, hand/foot is redundant when an individually named finger, e.g. index finger, or the great toe has been specified in a description. For example,
Bone structure of phalanx of left index finger (body structure)
🟢correct
Bone structure of phalanx of index finger of left hand (body structure)
🟠 it is not wrong, but 'hand' is redundant
Bone structure of phalanx of left index finger of hand (body structure)
🟠 it is not wrong, but 'hand' is redundant
This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.
SNOMED CT accepts tumor concepts, as long as they are included in the International Classification of Diseases for Oncology (ICD-O). ICD-O has two coding systems for coding the site (topography) and the histology (morphology) of the neoplasm:
Topographical - Anatomical site of origin or the organ system
Morphological - Tumor cell type or histology and behavior, i.e. malignant versus benign
The topography code describes the site of origin of the neoplasms. The morphology code describes the cell type of the tumor and its biologic activity, in other words, the characteristics of the tumor itself. The morphology code, combined with the appropriate topography, expresses the complete morphological assessment as stated by the pathologist.
Although the behavior of a neoplastic morphological type is implicit knowledge in the pathology community, the behavior (benign, in situ, uncertain behavior, or malignant) must be included in the description in SNOMED CT to aid users, terminology authors, and mappers; and because over time, the behavior of a certain neoplastic cell type may change depending upon the latest scientific understanding, so clarity is important.
SCT intends to avoid adding concepts that conflate the localization of a specific tumor type in a topographic location as opposed to a neoplastic cell type that is derived from a specialized cell in an organ, e.g. adenocarcinoma vs. renal clear cell carcinoma. One is general; the other is specific to a cell type.
The naming pattern utilized for gene-derived neoplastic morphology terms will align with the WHO Classification of Tumours (IARC 'Blue Books'). Gene acronyms are not required to be expanded. This policy is an exception to SNOMED CT's requirement for expansion of acronyms.
For example,
1186933006 |SMARCA4-deficient undifferentiated tumor (morphologic abnormality)|. The gene SMARCA4 is not required to be named with the expanded form of SWI/SNF Related, Matrix Associated, Actin Dependent Regulator Of Chromatin, Subfamily A, Member 4.
For more information
Visit ICD-O at