Overview
It arises deep, between the two heads of the gastrocnemius, and its belly contains much tendinous tissue. Its tendon winds around the gastrocnemius tendon, becomes superficial and forms a cap over the calcaneal tuber, attached to it on both sides. It continues along the plantar surface of the metatarsus and splits into two branches, one for each main digit (III and IV). Each branch forms a sleeve (manica flexoria) through which the deep digital flexor tendon passes.
Origin
Supracondylar fossa of the femur (fossa supracondylaris).
Insertion
Middle phalanges of digits III and IV.
Action
Flexes the digits and extends the tarsus.
Innervation
Tibial nerve (n. tibialis).
Clinical relevance
- It is part of the common calcanean tendon: its laceration or rupture makes the hock drop.
- In some cases of spastic paresis in calves this muscle is involved together with the gastrocnemius.