Internal pudendal vein
The internal pudendal vein is located in the gluteal (buttock) region.
It lies between the sacrospinous ligament and the sacrotuberous ligament in the buttock, and posterior to (behind) the ischial spine, which is an area of bone that sticks out of the lower part of the pelvis.
The internal pudendal vein lies alongside the internal pudendal artery, which brings oxygenated blood to the same region. The pudendal nerve also lies alongside these two blood vessels and innervates the same region. The internal pudendal vein, internal pudendal artery, and pudendal nerve are bundled together by a thick sheet of tissue called the obturator internus fascia. This bundled group is called the pudendal canal.
The internal pudendal vein drains oxygen-depleted blood from the perineum, which is the area between the exterior genitals and anus, and the external genitalia. The drained region includes the bulb of the penis (in males) or clitoris (in females), the anal region, and the urogenital region.
Tributaries of the internal pudendal vein include the vein of the bulb (in males), the posterior labial vein (in females), the scrotal vein (in males), and the inferior rectal vein. The internal pudendal vein drains into the internal iliac vein. Despite its location, the deep dorsal vein, which drains the erectile bodies of the penis (in men), does not pass into the internal pudendal vein.