The pudendal nerve (choice D) leaves the pelvis through the greater sciatic foramen, passing between piriformis and coccygeus, then passes around the ischial spine and reenters the pelvis via the lesser sciatic foramen. From there, it enters Alcock's canal on the lateral wall of the ischiorectal fossa with the internal pudendal vessels. Transvaginal pudendal nerve block is performed to anesthetize the perineum when performing obstetric maneuvers to facilitate vaginal delivery. Local anesthetic can be injected around the pudendal nerve trunk as it passes back into the lesser sciatic foramen, 1 cm below and medial to the ischial spine.

Gluteal Region

The superolateral quadrant of the buttocks is considered the safest place for dorsogluteal (deep IM) injections. However, damage to the gluteal and sciatic nerves can still result from injfections into this region.

Most intragluteal injections should target the anterolateral gluteal area (von Hochstetter triangle) to minimize the possibility of nerve damage.

Sciatic nerve can be damaged via injections into high-risk areas such as the superomedial, inferomedial, or inferolateral quadrants of the buttock.