Semimembranosus - Podcast Version 0:00 / 0:00 1x 0.25x 0.5x 0.75x 1x 1.25x 1.5x 1.75x 2x The semimembranosus is a muscle within the posterior compartment of the thigh. It is located deep to the semitendinosus muscle within the medial aspect of the posterior thigh. Attachments: Originates from the ischial tuberosity (more superiorly than the origin of the semitendinosus and biceps femoris). Attaches to the medial tibial condyle. 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 (2026) Fig 1The muscles of the posterior thigh. By TeachMeSeries Ltd (2026) 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 Pro Feature - Dissection Atlas Prosection of the posterior compartment of the thigh. Prosection of the posterior compartment of the thigh. You've Discovered a Pro Feature Access our Dissection Image Library Enhance your understanding with high-resolution dissection images showcasing real-life anatomy. Learn More Frequent questions What is the semimembranosus muscle? The semimembranosus is a muscle located in the posterior compartment of the thigh, positioned deep to the semitendinosus. It plays a key role in movements of the leg and thigh. Where does the semimembranosus muscle attach? This muscle originates from the ischial tuberosity and attaches to the medial condyle of the tibia. Its superior origin compared to the semitendinosus and biceps femoris is significant for its function. What actions does the semimembranosus perform? The semimembranosus facilitates flexion of the leg at the knee, extension of the thigh at the hip, and medial rotation of both the thigh and leg. These actions are essential for various movements, including walking and running. What is the innervation of the semimembranosus muscle? The semimembranosus is innervated by the tibial part of the sciatic nerve. This innervation is crucial for its motor function in the posterior thigh. What is the blood supply to the semimembranosus muscle? The blood supply to the semimembranosus comes from the profunda femoris artery. Adequate blood flow is vital for the muscle's health and function. Rate This Article