Sartorius Muscle

It is the longest muscle of the human body along with the quadriceps femoris, which belongs to the anterior muscles of the thighs. It is found slanted throughout the course of thighs, which arises from the anterior superior iliac spine and crosses to the medial side of the thighs.

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Finally, it inserts to the medial side of the proximal tibia. Due to the slanted nature of the sartorius muscle, it flexes, abducts and externally rotates the thighs, flexes, and internally rotates the leg. 

Structure 

The muscle sartorius originates from the anterior superior iliac spine and a part of this muscle is between the anterior superior iliac spine and anterior inferior iliac spine. Sartorius’s muscle runs slantly across the upper and anterior part of the thigh, and it passes behind the medial condyle of the femur to the end in a tendon. This tendon curves to the front to join the gracilis muscles and the semitendinosus muscles in the pes anserinus, where it attaches to the upper surface of the tibia.

The upper portion of the sartorius muscle forms a lateral border of the femoral triangle and a point, where it crosses the adductor longus marks the apex of the triangle. The depth of the sartorius and its fascia is the adductor canal, through which the saphenous nerve passes, the femoral artery and vein, and the nerve to the vastus medialis.

Sartorius Muscle Origin and Insertion 

Origin of sartorius muscle - The origin of the sartorius muscle is found in the anterior superior iliac spine and the upper half of the notch between the anterior superior iliac spine and the anterior inferior iliac spine. The fibre of this muscle forms a thin, flat muscle, which extends inferomedially across the anterior surface of the thigh. 

Thus muscle descends vertically through the medial aspect of the thigh. And the muscle also crosses the medial side of the knee joint, which inserts on to the medial aspect of the proximal tibia, anterior to the gracilis and semitendinosus muscles.  

Sartorius muscle insertion - The insertion of the three muscles forms a wide aponeurotic sheath known as the anserinus. In which some of the fibres (inferior part of the tendon) blend with the medial collateral ligament of the knee joint, and the deep fascia over the medial aspect of the leg. While some of the superior fibres blend with the knee joint capsule, these connections contribute to the medial stability of the knee joint. 

Functions of the Sartorius Muscle 

Some of the functions of the sartorius muscles are - it crosses both the hip and the knee joint, which produces the movement on both of them. And at the hip joint, it is capable of flexion, external rotation and abduction of the leg. The shrinkage action of sartorius muscle can also cause flexion to the knee joint and inward, or medial, rotation of the tibia against the femur.

The combination of all these movements stated above allows a person to sit in an area with opposite legs. However, the movements made by the sartorius cut were not limited to that one function. Sartorius muscle also may play an important role in climbing.

The Blood Supply in the Sartorius Muscle

As sartorius muscle is a long muscle it requires extensive vascular supply from several sources:

• The third proximal receives the vascular supply from the branch of femoral, deep femoral branches, lateral femoral arteries and/or quadriceps artery (branch of the deep femoral artery or lateral circumflex).

• The middle third is provided by the femoral artery branches.

• A third of the distal receives blood supply to the female artery and the descending vein descends.

Do You Know?

What causes Sartorius muscle pain? If the bursa under the muscles of the sartorius, gracilis, and semitendinosus are prone to overuse or injury, a person can develop pain. This condition is more common in athletes from overuse and is a common cause of knee weakness and pain.