Corpus: Semitendinosus muscle

The semitendinosus muscle is a muscle that belongs to the thigh or ischiocrural muscles.

The semitendinosus muscle originates from the ischial tuberosity of the ischium and inserts on the medial side of the tibial shaft. Almost the entire distal half of the muscle consists of its insertion tendon, giving the muscle its name and making it easy to recognize in situ.

The tendon of the semitendinosus muscle, along with the tendons of the sartorius and gracilis muscles, forms the superficial pes anserinus, a goosefoot-shaped connection of these three tendons.

In some cases, an oblique intersection tendinea occurs within the muscle belly of the semitendinosus muscle.

The semitendinosus muscle is innervated by the muscular branches of the tibial nerve (L5-S2).

The semitendinosus muscle functions to flex the knee joint and extend the hip joint. It also supports the internal rotation of the tibia.

In orthopedics and trauma surgery, the semitendinosus muscle and its tendon play an important role as an autograft. The attachment tendon of the semitendinosus muscle can be transplanted during a tendonplasty, such as in the context of a cruciate ligament rupture. The detached muscle is then fixed to the neighboring semimembranosus muscle, as both muscles share the same joint-mechanical function.