Two accessory muscles of leg: potential source of entrapment of posterior tibial vessels

Accessory muscles can be found in any part of the body. In most of the regions, they go unnoticed. However, in some cases, they become symptomatic or of cosmetic concern. In this particular case, the presence of two accessory muscle slips was observed in the flexor compartment of the leg. Among the two, the first accessory muscle belly connected the lower part of flexor hallucis longus to the tibialis posterior. The muscle crossed superficial to the posterior tibial vessels. The second accessory muscle took origin from the connective tissue around the lower part of the posterior tibial vessels and was inserted to the upper part of the lateral border of tibia near the attachment of the interosseous membrane. One of the accessory muscles crossed the posterior tibial vessels, while the other surrounded them. The above accessory muscles were supplied by the branches of tibial nerve.