Sartorius
| Pronuncation | sar-TORE-ee-us |
| Derivation | Refering to the tailor (as in sartorial), who traditionally sits on the floor in a cross-legged position made possible by this muscle. |
| Origin | Anterior superior iliac spine of pelvis. |
| Insertion | Upper medial surface of the tibia. |
| Action | Flexes the leg at both the hip and the knee, and rotates the leg laterally. |
Sartorius spirals from the outside of the pelvis to the inside of the leg below the knee. Drawing the axis of this muscle from origin to insertion is sufficient to describe much of the bulk of the thigh, and this line creates a useful plane break between the adductors on the inner thigh and the extensors on the front.
This strong ribbon of muscle either sits flatly on or disappears behind vastus medialis in a frontal view. It ends in a tendon whose bulk combines with that of gracilis and semitendinosus. This bulk fills out the medial side of the knee, and runs in front of the calf muscle (gastrocnemius) when viewed from the front.