Tensor fasciae suralis muscle

The tensor fasciae suralis muscle is an uncommon accessory muscle in the popliteal fossa. It can be an unusual cause of a popliteal fossa soft-tissue swelling or mass. 

Summary

• origin: may arise from the distal aspect of any of the hamstring muscles, in the majority of reported cases it originates from the distal semitendinosus muscle
• insertion: may insert into the posterior fascia of the leg, into the medial head of the gastrocnemius, or via a long thin tendon onto the superficial aspect of the Achilles tendon
• innervation: tibial nerve

Gross anatomy

A tensor fasciae suralis is located superficially in the popliteal fossa, between the semitendinosus and semimembranosus muscles medially and the biceps femoris muscle laterally. 

Radiographic features

A tensor fasciae suralis can usually be identified with ultrasound or MRI, which delineate an accessory muscle in the popliteal fossa, lateral to the semitendinosus tendon and posterior to the semimembranosus.

Differential diagnosis

The accessory semimembranosus muscle, similar in location but arising from the semimembranosus, has also been described.

History and etymology

According to some reports, it is thought to have been first described by R A Bergman et al. in 1873 ³.