Inferior anal nerves

The inferior rectal nerves (inferior anal nerves, inferior hemorrhoidal nerve) usually branch from the pudendal nerve but occasionally arises directly from the sacral plexus; they cross the ischiorectal fossa along with the inferior rectal artery and veins, toward the anal canal and the lower end of the rectum, and is distributed to the sphincter ani externus (external anal sphincter, EAS) and to the integument (skin) around the anus.

Branches of this nerve communicate with the perineal branch of the posterior femoral cutaneous and with the posterior scrotal nerves at the forepart of the perineum.

Cutaneous innervation below the pectinate line and external anal sphincter.

This article incorporates text in the public domain from page 968 of the 20th edition of Gray's Anatomy (1918)