Anatomical Structure and Location of the Semimembranosus Muscle

Description

Running along the posteromedial thigh, the semimembranosus is shown arising from the ischial tuberosity and descending deep to the semitendinosus toward the medial side of the knee. Distally, its broad tendon courses posterior to the medial femoral condyle and inserts on the posterior aspect of the medial tibial condyle, just inferior to the joint line. The femur spans from the acetabulum to the distal condyles, while the tibia and fibula continue inferiorly, with the fibula positioned lateral to the tibia. Medially at the knee, the semimembranosus sits posterior to the medial collateral ligament and adjacent to the posteromedial joint capsule. This anatomy matters because the semimembranosus is a key landmark in the posteromedial corner of the knee, where its expansions contribute to the oblique popliteal ligament and influence posterior capsular stability. Pain or snapping along the posteromedial knee often traces to semimembranosus tendinopathy or insertional bursitis (the semimembranosus bursa), and swelling in this region can communicate with a Baker cyst through the gastrocnemius semimembranosus interval. Its position also frames surgical thinking during hamstring tendon harvest and during evaluation of posteromedial meniscal tears, where tenderness can be difficult to localize without a clear map of the tendons and condyles. A frequent site of confusion. Use this plate in lower-limb anatomy teaching, sports medicine lectures on hamstring injury patterns, and orthopedic or radiology materials that need accurate tendon to condyle relationships at the knee. It also fits well in patient education for posteromedial knee pain and in surgical atlases covering posterior capsular anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.