Sartorius (anatomy)

Sartorius is the longest muscle in the body. It is a narrow strap muscle that is the most superficial muscle in the thigh. The medial border of sartorius forms the lateral border of the femoral triangle.

It originates from the anterior superior iliac spine and the notch just inferior to this point. It traverses the thigh inferomedially. At the medial side of the knee it becomes more tendinous and forms a broad aponeurosis. At this point it forms part of the roof of the adductor canal. It inserts into the upper, medial surface of the shaft of the tibia just anterior to the insertion of gracilis and semitendinosus. The confluence of sartorius, gracilis and semitendinosus form the 'pes anserinus'.

Anomalies of sartorius have been described including:

• its absence
• an extra head attached to the pectineal line or the femoral sheath

The vascular supply of sartorius is segmental in nature. Most branches arise from the femoral system:

• superior blood supply may receive contributions from:
  • common femoral artery
  • superficial femoral artery
  • profunda femoris
  • lateral circumflex femoral artery
  • superficial circumflex iliac artery
• middle group blood supply arises from the superficial femoral artery
• inferior group blood supply may receive contributions from:
  • superficial femoral artery
  • descending genicular artery

Its actions are:

• at the hip:
  • flexion
  • abduction
  • lateral rotation of thigh
• at knee:
  • flexes
  • medially rotates lower limb

It is innervated by the anterior division of the femoral nerve (L3, L4).

Sartorius may be tested by viewing its contraction and palpation of its bulk when it contracts against gravity with hip flexion on standing.