The semitendinosus is a muscle within the posterior compartment of the thigh. It is situated on the medial aspect of the posterior thigh and superficial to the semimembranosus muscle. Attachments: Originates from the ischial tuberosity of the pelvis and attaches to the medial surface of the tibia. Actions: Flexion of the leg at the knee joint. Extension of thigh at the hip. Medially rotates the thigh at the hip joint and the leg at the knee joint. Innervation: Tibial part of the sciatic nerve. Blood Supply: Profunda femoris artery By TeachMeSeries Ltd (2025) Fig 1The muscles of the posterior thigh. By TeachMeSeries Ltd (2025) Fig 2Cross section of the thigh, showing the position of the major muscle groups. Pro Feature - 3D Model You've Discovered a Pro Feature Access our 3D Model Library Explore, cut, dissect, annotate and manipulate our 3D models to visualise anatomy in a dynamic, interactive way. Learn More Print Article Rate This Article