The Perforating Cutaneous Nerve (n. clunium inferior medialis) usually arises from the posterior surface of the second and third sacral nerves. It pierces the lower part of the sacrotuberous ligament, and winding around the inferior border of the Glutæus maximus supplies the skin covering the medial and lower parts of that muscle.
The perforating cutaneous nerve may arise from the pudendal or it may be absent; in the latter case its place may be taken by a branch from the posterior femoral cutaneous nerve or by a branch from the third and fourth, or fourth and fifth, sacral nerves.
The Pudendal Nerve (n. pudendus; internal pudic nerve) derives its fibers from the ventral branches of the second, third, and fourth sacral nerves. It passes between the Piriformis and Coccygeus muscles and leaves the pelvis through the lower part of the greater sciatic foramen. It then crosses the spine of the ischium, and reënters the pelvis through the lesser sciatic foramen. It accompanies the internal pudendal vessels upward and forward along the lateral wall of the ischiorectal