Synonyms
Latin: Musculus semitendinosus
Definition
The semi-tendon muscle is a muscle of the posterior thigh muscles (the so-called ischiocrural muscles) and extends approximately from the lower edge of the pelvis to just below the inside of the knee joint, where it attaches to the upper inner shin. When the muscle contracts, it mainly bends the lower leg towards the thigh, but it can also support leg extension when the leg is raised towards the chest. The semi-tendon muscle bears its unusual name because the tendon with which it attaches to the shin is particularly long. It extends far into the thigh and takes up a large part of the muscle length, which is why the muscle is literally half muscle and half tendon. Its attachment tendon is also part of a famous anatomical structure: Together with the tendons of the Tailor Muscle (M. sartorius) and the Slender Muscle (M. gracilis) on the upper inner tibia, it forms a fan-shaped, three-part structure that looks like a goosefoot and is therefore anatomically called “Pes anserinus”.
History
Base: Upper inner shinbone, so-called “superficial goosefoot” (Pes anserinus superficialis) Origin: cusp of the ischium, part of the pelvis (Tuber ischiadicum) Innervation: N. tibialis (segment L5-S2)
Function
Due to its course, the muscle supports movement in both the hip joint and the knee joint. In the hip joint it has the function of an extensor and adductor. An extension in the hip joint occurs, for example, when extending the bent thigh, but also when standing upright.
Adduction is the Latin word for approach, i.e. the muscle of the half tendon can bring the spread leg back to the body. In the knee joint, the muscle supports flexion (flexion) and inward rotation (internal rotation). In other words, movements in which the lower leg is guided towards the thigh, such as when standing on one leg, or the lower leg is rotated inwards.