Henry Gray (18251861). Anatomy of the Human Body. 1918.
The Nerve to the Piriformisarises from the dorsal division of the second sacral nerve, or the dorsal divisions of the first and second sacral nerves, and enters the anterior surface of the muscle; this nerve may be double.
FIG. 829 Dissection of side wall of pelvis showing sacral and pudendal plexuses. (Testut.) (See enlarged image)
The Superior Gluteal Nerve (n. glutæus superior) arises from the dorsal divisions of the fourth and fifth lumbar and first sacral nerves: it leaves the pelvis through the greater sciatic foramen above the Piriformis, accompanied by the superior gluteal vessels, and divides into a superior and an inferior branch. The superior branch accompanies the upper branch of the deep division of the superior gluteal artery and ends in the Glutæus minimus. The inferior branch runs with the lower branch of the deep division of the superior gluteal artery across the Glutæus minimus; it gives filaments to the Glutæi medius and minimus, and ends in the Tensor fasciæ latæ.
The Inferior Gluteal Nerve (n. glutæus inferior) arises from the dorsal divisions of the fifth lumbar and first and second sacral nerves: it leaves the pelvis through the greater sciatic foramen, below the Piriformis, and divides into branches which enter the deep surface of the Glutæus maximus.
The Posterior Femoral Cutaneous Nerve (n. cutaneus femoralis posterior; small sciatic nerve) is distributed to the skin of the perineum and posterior surface of the thigh and leg. It arises partly from the dorsal divisions of the first and second, and from the ventral divisions of the second and third sacral nerves, and issues from