Semitendinosus

Musculus semitendinosus

Lower Body Lower BodyLegsHamstringsPosterior ChainHinge

The semitendinosus is a medial hamstring noted for its remarkably long distal tendon, which inserts at the pes anserinus and helps medially rotate the tibia. It extends the hip and flexes the knee alongside its fellow hamstrings. Its tendon is frequently harvested for ACL reconstruction, and in training it responds well to both hip-hinge and leg-curl movements while also contributing to knee stability against valgus stress.

Actions

Knee flexion, Hip extension, Medial rotation of the leg at the knee (when knee flexed), Medial rotation of the thigh (when hip extended)

Origin

Lower medial part of the ischial tuberosity, via a tendon shared with the long head of biceps femoris (conjoint tendon)

Insertion

Upper part of the medial surface of the tibia (pes anserinus), behind the attachments of sartorius and gracilis

Innervation

Tibial division of the sciatic nerve (L5-S2)

Blood supply

Inferior gluteal artery and perforating branches of the profunda femoris artery

Wikipedia ↗

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