Due to its long course, the Musculus Satorius fulfills a function in both the hip joint and the knee joint. Its origin at the hip causes the hip to bend (flex) when the muscle contracts. It can also rotate the thigh outwards in the hip and lift it laterally (abduction).
Also in the knee joint, together with the quadriceps muscle, it belongs to the flexors of the knee. Here, its lateral attachment means that it can also rotate the knee inwards. If all these five functions of the muscle are performed simultaneously, the leg is in the cross-legged position.
This is where the name of the muscle comes from. Overall, however, it is not primarily responsible for any of the movements, but forms functional units with several muscles. The force that the muscle can apply is approximately twice as great in the hip joint as in the knee joint. The Sartorius muscle is innervated by the femoral nerve. This is a nerve that originates from the lumbar nerve plexus (segments L 2-4) and supplies not only the sartorius muscle but also other muscles in the front thigh.
Position and course
The Musculus sartorius (also called “Tailor muscle“) is an approximately 50cm long, narrow muscle, which is counted among the group of thigh muscles. It runs very superficially on the front side of the body and runs across the thigh. The origin is located at the front outside of the hip bone (Spina iliaca anterior superior).
From there, it spans the other thigh muscles in a spiral and, together with two other muscles, attaches to the inner side of the tibia via a tendon structure (Pes anserinus superficialis). Topographically, the Sartorius muscle has another special feature: it laterally delimits the “Trigonum femorale“, an opening through which all the large and important vessels of the leg pass. For this reason, the sartorius muscle is often used as a guide for surgery on the femoral artery.
