PA Anatomy: Pelvis: Case 4

The openings in the posterior pelvis are the greater and lesser sciatic foramina. The superior margin of the greater sciatic foramen is shown in dark blue. The pyriformis muscle passes through the greater sciatic foramen and is pink. The ischial tuberosity is medium blue. The ischial spine is light green. The sacrospinous ligament is yellow. The sacrotuberous ligament is orange

The course of the pudendal nerve is shown in purple. It passes laterally out of the pelvis through the greater sciatic formen (near pyriformis), and then loops over the sacrospinous ligament to come back in a medial direction through the lesser sciatic foramen, to reach the perineum.