Quadratus plantae with reversed muscular–tendinous pattern: Functional and clinical insights

The flexor digitorum accessorius (quadratus plantae) plays an important role in optimizing the action of flexor digitorum longus by correcting its oblique pull during toe flexion. Variations in its morphology are known but remain underreported. During routine cadaveric dissection, an unusual architectural variation of the flexor digitorum accessorius was observed, wherein the lateral head was predominantly muscular while the medial head was largely tendinous, representing a reversal of the commonly described pattern. Such a variation may influence plantar biomechanics, surgical approaches to the sole, and radiological interpretation. The present case highlights the importance of recognizing head-specific morphological variations of intrinsic foot muscles and discusses their functional and clinical relevance.