The structure indicated is the tensor fasciae latae muscle.

The tensor fasciae latae muscle is one of the muscles of the gluteal region. The muscles in the gluteal region are divided into a superficial and deep group. There are four muscles of the superficial group:

1. Gluteus maximus
2. Gluteus medius
3. Gluteus minimus
4. Tensor fasciae latae

There are 5 muscles in the deep group:

1. Gemellus superior
2. Gemellus inferior
3. Quadratus femoris
4. Piriformis
5. Obturator internus

The tensor fasciae latae muscle is the most anteriorly situated muscle of the gluteal region and is continuous with the iliotibial tract (iliotibial band), which is the fibrous tract of tissue formed from the lateral thickening of the deep fascia of the thigh. The iliotibial tract attaches to the lateral condyle of the tibia to provide lateral stability to the knee joint. Both the gluteus maximus and the tensor fasciae latae insert onto the iliotibial tract. The deep fascia of the thigh is the “fascia lata” – the literal Latin translation. The name “tensor fasciae latae” therefore comes from the function of this muscle in tensing the fascia lata/deep fascia.

Origin: Anterior superior iliac spine and outer edge of the iliac crest.

Insertion: Iliotibial band

Action: Hip abduction, medial rotation, assists hip flexion, stabilises hip and knee by placing tension in iliotibial band.

Innervation: Superior gluteal nerve

Learn more about the anatomy of the gluteal muscles in this tutorial.