Nerve to obturator internus
The nerve to obturator internus (also known as the obturator internus nerve[citation needed]) is a mixed (sensory and motor)[1] nerve providing motor innervation to the obturator internus muscle and gemellus superior muscle,[2][1] and sensory innervation to the hip joint.[2] It exits the pelvis through the greater sciatic foramen to innervate the gemellus superior muscle, then re-enters the pelvis to innervate the obturator internus muscle.[3][4][2] It emerges inferior to the piriformis muscle and exits the pelvis through the greater sciatic foramen.It travels round the base of the ischial spine[2] lateral to the internal pudendal artery and nerve, and - while doing so - issues a branch to the gemellus superior, which enters the upper part of the posterior surface of the muscle.[citation needed] This article incorporates text in the public domain from page 957 of the 20th edition of Gray's Anatomy (1918)