The sacrotuberous and sacrospinous ligaments convert the greater and lesser sciatic notches into foramina.
Reproduced with permission from: Clinically Oriented Anatomy, 7th ed, Moore KL, Dalley AF, Agur AM (Eds), Lippincott Williams & Wilkins, Philadelphia 2013. Copyright © 2013 Lippincott Williams & Wilkins.
www.lww.com.