M66.379 Spontaneous rupture of flexor tendons, unspecified ankle and foot

ICD-10-CM M66.379: Spontaneous rupture of flexor tendons, unspecified ankle and foot

ICD-10-CM code M66.379 designates a diagnosis of spontaneous rupture of flexor tendons in an unspecified ankle and foot. The code is an active terminology concept classified under the broader parent category of ankle and foot flexor tendon ruptures. This reference page synthesizes official terminology records to explain the code's structural meaning. 1 2 3

Plain-language overview

ICD-10-CM code M66.379 identifies a pathologic function involving the spontaneous rupture of flexor tendons located in the ankle and foot, without specifying the exact side or location. 1

What this code represents

The official display label for diagnosis code M66.379 is spontaneous rupture of flexor tendons, unspecified ankle and foot, and the terminology record currently maintains an active status. 1

Within the ICD-10-CM terminology hierarchy, M66.379 is a narrower concept that falls under the parent concept M66.37, which denotes spontaneous rupture of flexor tendons of the ankle and foot. 1

Coding details

The official terminology record for M66.379 includes the published abbreviation spontaneous rupture of flexor tendons, unsp ankle and foot, providing a shortened representation for this specific diagnosis. 1

Code M66.379 is explicitly listed alongside M66.37 in official code system browsing tools, confirming its integration into the standard ICD-10-CM code set for ankle and foot flexor tendon ruptures. 3

Documentation considerations

The official terminology record for M66.379 assigns the semantic type of pathologic function to this diagnosis, establishing the fundamental clinical nature of the condition for coding purposes. 1

What the sources add

The National Cancer Institute terminology record establishes the exact preferred name, active status, and parent concept for M66.379, while the code system browser independently verifies its inclusion in the ICD-10-CM set. 1 3

The EVS Explore portal explicitly associates the exact code M66.379 with its official description, confirming the terminology mapping for spontaneous rupture of flexor tendons in an unspecified ankle and foot. 2

Questions to verify

Reviewers may verify whether the EVS Explore portal lists any asserted or inherited role relationships pointing from the M66.379 concept to other terminology concepts within the hierarchy. 2

Sources

1. ICD-10-CM M66.379 terminology record — National Cancer Institute Enterprise Vocabulary Services; accessed 2026-07-27.
2. EVS Explore — evsexplore.semantics.cancer.gov; accessed 2026-07-27.
3. Browse Code Systems — vsac.nlm.nih.gov; accessed 2026-07-27.