> 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/clinical-finding-and-disorder/clinical-finding-and-disorder-modeling/specific-clinical-finding-and-disorder-modeling/malformation-deformity-anomaly.md).
# Malformation, deformation, anomaly
**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 word *anomaly* is, by itself, ambiguous as it may mean either a structural or functional abnormality, depending on the body structure to which it is applied. Concepts using the term *anomaly* must be evaluated to determine whether it represents a structural or functional abnormality. Using the term "anomaly" in new concept FSNs is not allowed. The terms "structural abnormality" should be used when it is unclear whether the morphology results from malformation or deformation.
A *deformity* is a structural abnormality that is due to an extrinsic physical force. Newly created concepts representing a deformity should be considered disorders.
*A malformation* is a structural abnormality that results from intrinsically disordered development.
* For example,
* *Congenital anomaly of* is currently modeled as a structural abnormality but is not the same as *C* *ongenital malformation* (structural abnormality due to intrinsically disordered development present at birth). Therefore, it can be regarded as having the more general meaning of *structural abnormality present at birth*.
When referring to a broad term to denote an intrinsic structural abnormality (e.g., Structural abnormality of fetal bladder) and plan to include 49755003 |Morphologically abnormal structure (morphologic abnormality)| in the model, use the pattern *Malformation of fetal X* or *Congenital malformation of X*.
{% hint style="success" %}
**See other related section in the guide**
* Genetic, developmental, congenital, and physical origin
* Acquired abnormality of congenital anomaly
* Congenital
{% endhint %}
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