Corpus: Lesser ischiadic foramen

The lesser sciatic foramen is a passageway for important pathways in the pelvic region that is limited by two ligaments.

The sacrospinous ligament is the cranial boundary and the sacrotuberous ligament is the caudal boundary.

• Internal pudendal artery: The internal pudendal artery originates from the internal iliac artery and runs to the urogenital region. It supplies the rectum and structures in the urogenital region.
• Internal pudendal vein: The catchment area of the internal pudendal vein includes the urogenital region. It flows into the internal iliac vein.
• Pudendal nerve: The pudendal nerve supplies the sphincter ani externus muscle, the muscles in the urogenital region and the skin on the dorsal side of the external genitalia.
• Internal obturator nerve: Supplies the internal obturator muscle.

The four structures mentioned first pass through the greater ischial foramen, then pass around the ischial spine and enter the lesser ischial foramen.

The internal obturator muscle also passes through the lesser sciatic foramen to the trochanteric fossa on the femur.

See also: Foramen ischiadicum majus