The ischial spine is part of the posterior border of the body of the ischium bone of the pelvis.

It is a thin and pointed triangular eminence, more or less elongated in different subjects.

The pudendal nerve travels close to the ischial spine.

[3] The ischial spine can serve as a landmark in pudendal anesthesia, as the pudendal nerve lies close to the ischial spine.

[3][4] This article incorporates text in the public domain from page 235 of the 20th edition of Gray's Anatomy (1918)