> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1.md).

# Anatomical Structure Modeling

<mark style="color:$danger;">**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.**</mark>

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.

## Pages in this section:

* [Body parts and regions](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/body-parts-and-regions.md)
* [Cardiovascular System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/cardiovascular-system.md)
* [Digestive System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/digestive-system.md)
* [Ear](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/ear.md)
* [Endocrine System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/endocrine-system.md)
* [Eye](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/eye.md)
* [Genitourinary system](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/genitourinary-system.md)
* [Integumentary System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/integumentary-system.md)
* [Lymphatic, Immune, Hematologic, Hematopoietic systems](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/lymphatic-immune-hematologic-hematopoietic-systems.md)
* [Musculoskeletal System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/index.md)
  * [Anatomy relating to the spine](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/index/anatomy-relating-to-the-spine.md)
* [Nervous System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/nervous-system.md)
* [Respiratory System](/education/snomed-ct-education-editorial-guide/readme/authoring/domain-specific-modeling/body-structure/index-1/respiratory-system.md)

{% hint style="success" %}
**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.
{% endhint %}

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