Lesser Sciatic Notch Of The Hipbone Shown, Posterior View

Description

Hipbone landmarks dominate the posterior pelvis in this illustration, centering on the lesser sciatic notch (incisura ischiadica minor) of the ischium. The curved indentation lies inferior to the ischial spine and superior to the ischial tuberosity, with the broader greater sciatic notch positioned superiorly on the posterior border. From this posterior perspective, the notch reads as a concave break in the ischial margin where ligamentous bridges would complete the outline into the lesser sciatic foramen. A tight space. Clinically, the lesser sciatic notch matters because it forms the bony boundary of the lesser sciatic foramen when spanned by the sacrospinous ligament (from ischial spine to sacrum) and sacrotuberous ligament (from ischial tuberosity to sacrum), a corridor used by the tendon of obturator internus as it exits the pelvis and by the pudendal neurovascular bundle as it re-enters the perineum after passing around the ischial spine. That relationship underpins common teaching around pudendal nerve entrapment near the ischial spine and the use of the ischial spine as a landmark for transvaginal or transperineal pudendal nerve block. Posterior lighting and clean edge definition make the ischial spine and the notch’s superior and inferior lips easy to distinguish, which helps when correlating dry bone anatomy with operative landmarks. Use this illustration in gross anatomy and pelvic floor courses when introducing the sciatic notches, the conversion to greater and lesser sciatic foramina, and the transition zones between pelvis, gluteal region, and perineum. It also suits surgical education materials covering pudendal nerve block technique, posterior approaches to the pelvis, and orthopaedic discussions of pelvic ring landmarks on the os coxae. Anatomical accuracy verified by SciePro's Medical Advisory Board.