The semitendinosus is the most medial of the three hamstring muscles and has the longest tendon relative to its muscle belly, which forms in the lower third of the thigh before continuing to the pes anserinus insertion on the medial tibia. This long tendon makes it the most commonly harvested hamstring for ACL reconstruction, as it provides a strong and predictable graft with a minimal functional deficit after harvest.
| Origin | Ischial tuberosity via the conjoined tendon shared with the biceps femoris long head |
|---|---|
| Insertion | Upper medial surface of the tibia via the pes anserinus, alongside gracilis and sartorius |
| Nerve Supply | Tibial nerve (L5, S1, S2) |
| Blood Supply | Inferior gluteal artery; Perforating branches of the deep femoral artery |
| Actions |
|
|---|
Its internal tibial rotation when the knee is flexed is the functional opposite of the biceps femoris and is important for controlling tibial rotation during cutting movements and the de-screw phase of knee unlocking.
Semitendinosus harvest for ACL reconstruction produces temporary hamstring weakness that resolves as the muscle regenerates from the remaining proximal belly. The regenerated muscle-tendon unit is visible on MRI by 12 months in most patients. Semitendinosus strains at the proximal musculotendinous junction are less common than biceps femoris strains but occur with the same sprinting mechanism.
The semitendinosus tendon is the most posterior and medial of the pes anserinus tendons, palpable as a firm cord just posterior to the gracilis at the medial knee during resisted knee flexion with internal tibial rotation.
Proximal musculotendinous junction tear from sprinting producing posterior thigh pain, less common than biceps femoris strains but managed identically with progressive loading rehabilitation.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
