Fascia · Thigh

Lateral intermuscular septum

Septum intermusculare femoris laterale

The strongest of the three partitions inside the thigh, running from the deep surface of the iliotibial band down to the rough ridge on the back of the femur and on to the bone just above the outer knee. It is the boundary between the front of the thigh and the back: vastus lateralis takes origin from its front face, the short head of biceps femoris from its back face. Because it is anchored to bone along its whole length and to a taut band at its outer edge, it holds its shape while the thigh muscles work rather than being pushed aside by them. The perforating branches of the profunda femoris artery cross it close to the bone as they wind round the femur to supply vastus lateralis.