The fascia lata is the deep fascia of the thigh.
It is an investment for the whole of the thigh, but varies in thickness in different parts.
Thus, it is thicker in the upper and lateral part of the thigh, where it receives a fibrous expansion from the Gluteus maximus, and where the Tensor fasciae latae is inserted between its layers; it is very thin behind and at the upper and medial part, where it covers the Adductor muscles, and again becomes stronger around the knee, receiving fibrous expansions from the tendon of the Biceps femoris laterally, from the sartorius medially, and from the Quadriceps femoris in front.
The fascia lata is attached, above and behind, to the back of the sacrum and coccyx; laterally, to the iliac crest; in front, to the inguinal ligament, and to the superior ramus of the pubis; and medially, to the inferior ramus of the pubis, to the inferior ramus and tuberosity of the ischium, and to the lower border of the sacrotuberous ligament.
From its attachment to the iliac crest it passes down over the Gluteus medius to the upper border of the Gluteus maximus, where it splits into two layers, one passing superficial to and the other beneath this muscle; at the lower border of the muscle the two layers reunite.