Hello again. This is Matt from Kenhub! And in this tutorial, we’re going to talk about the origin, insertion, innervation, and supply of the Sartorius muscle.
The sartorius muscle is a long, slim, superficially-running extensor of the thigh musculature. As you can see, it wraps like a sash across the superior aspect of the thigh.
The root “sartor” is actually Latin for “tailor.” The muscle is so-called because, when it does all of its job at once—yes, it has more than one. It’s quite the multipurpose muscle—the movement that results is the crossing of the leg in a seated position, one of the positions used when a tailor is fitting clothing. This is also when it is easiest to palpate the sartorius.
Topographically, the sartorius muscle forms the lateral border of the femoral triangle, which is also known as the scarpa’s triangle where the large vessels of the thigh pass through. For this reason, the muscle serves as a leading structure when surgically accessing the femoral artery.
The origin of the sartorius muscle is the anterior superior iliac spine of the pelvic bone. And from there, it runs spirally towards the knee region. It inserts at the pes anserinus medially from the tibial tuberosity. In its entire course, the muscle is covered by a duplication of the fascia lata which is a deep fascia that covers the thigh musculature in its entirety.
The femoral nerve is the nervous supply for this muscle, allowing it to do its many jobs.
The sartorius muscle is a two-joint muscle and moves both the hip and knee joint. Even though, anatomically, it is considered one of the extensors of the thigh, its contraction is what causes a flexion of the hip joint. This is because its insertion at the knee joint is located behind the flexion-extension access. It is also involved in the abduction and external rotation of the hip joint. In the knee joint, it forces a flexion and internal rotation of the knee.