Anatomical insights into a five-bellied gastrocnemius muscle: a case report

TL;DR

A rare case of a five-headed gastrocnemius muscle was found in a cadaver, highlighting anatomical variability and its clinical importance.

Contribution

The discovery of a five-headed gastrocnemius muscle adds to the understanding of anatomical variations and their potential clinical implications.

Findings

A five-headed gastrocnemius was identified in one leg with independent vascular and neural supply.

The contralateral leg showed a three-headed configuration including a gastrocnemius tertius.

Such variations may affect biomechanics and increase injury or misdiagnosis risks.

Abstract

The gastrocnemius (GM), a superficial posterior leg muscle, consists of medial and lateral heads and drives ankle plantarflexion and knee flexion. The morphological variability of this muscle has been extensively studied, especially the presence of a third head. Here, a novel five-headed configuration of the GM was identified during the cadaveric dissection of a 30-year-old male. The right GM exhibited five distinct heads, each with independent vascular and neural supply, whereas the contralateral limb displayed a three-headed configuration including a gastrocnemius tertius (GT). Detailed morphometric assessment was performed, and the developmental proximal attachment of the supernumerary heads and its clinical implications were discussed. Although often asymptomatic, these variants can alter biomechanics, narrow the popliteal corridor, and increase the risk of vascular or musculotendinous injury and misdiagnosis. Recognition of complex GM anatomy is therefore essential for surgeons and radiologists. Thus, this case highlights the developmental variability of the posterior leg compartment and underscores the importance of recognizing rare GM variants to ensure accurate diagnosis and safe clinical management.

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