Anatomy of pelvic arteries adjacent to the sacrospinous ligament: Importance of the coccygeal branch of the inferior gluteal artery

Objective: To describe the arterial vascular anatomy in the area of the sac rospinous ligament. Methods: Cadaver pelvises were dissected to reveal the anatomy of the sacro spinous ligament with emphasis on vascular and neuroanatomy. Flexible ruler s were used to measure the coccygeal branch in five hemipelvises. Results: The pudendal vessels and nerve pass immediately medial and inferio r to the ischial spine (within 0.5 cm of the spine) and behind the sacrospi nous ligament. The pudendal artery lies anterior to the sacrotuberous ligam ent, which passes behind the ischial spine to its attachment at the posteri or ischial tuberosity. The inferior gluteal artery originates from the post erior or the anterior branch of the internal iliac artery to pass behind th e sciatic nerve and the sacrospinous ligament. There is a 3- to 5-mm window in which the inferior gluteal vessel is left uncovered above the top of th e sacrospinous ligament and below the lower edge of the main body of the sc iatic nerve plexus. The coccygeal branch of the inferior gluteal artery pas ses immediately behind the midportion of the sacrospinous ligament and pier ces the sacrotuberous ligament in multiple sites. The main body of the infe rior gluteal artery leaves the pelvis by passing posterior to the upper edg e of the sacrospinous ligament and following the inferior portion of the sc iatic nerve out of the greater sciatic foramen. Conclusion: Sutures placed through the sacrospinous ligament at least 2.5 c m from the ischial spine along the superior border of the sacrospinous liga ment and without transgressing the entire thickness are in an area generall y free of arterial vessels. (Obstet Gynecol 1999;94:973-7. (C) 1999 by The American College of Obstetricians and Gynecologists.).