Unilateral Bicipital Plantaris Muscle: A Cadaveric Case Report

The plantaris muscle, a vestigial structure in humans, is a muscle of the posterior superficial compartment of the leg. This study addresses unilaterally bicipital (bifurcated) muscle bellies of the plantaris in a 58-year-old male cadaver. The plantaris functions proprioceptively to provide the central nervous system with information about the position of the gastrocnemius muscle and soleus muscle. However, the significance of this muscle in knee flexion and ankle plantar flexion is thought to be insignificant. The tendon of the plantaris muscle can be used for tendon grafts. Surgeons should be aware of this anatomical variant when considering feasible graft options, specifically for flexor tendons, and consider the potential for significant loss of proprioceptive input in the posterior compartment of the leg from its use as a graft. Clinically, it plays a role in the differential diagnosis of various pathologies of the posterior leg such as Achilles tendinopathy and tennis leg syndrome. A bicipital plantaris muscle belly can impact pathological manifestations and should be considered when palpating the popliteal fossa and Achilles tendon.