Report of an inferior rectal nerve variant arising from the S3 ventral ramus.

Anat Cell Biol. 2019 Mar;52(1):100-101. doi: 10.5115/acb.2019.52.1.100. Epub 2019 Mar 29.

Dupont G, Iwanaga J, Oskouian RJ, Tubbs RS.

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Abstract

In surgical approaches to the perineum in general and anal region specifically, considering the possible variations of the inferior rectal nerve is important for the surgeon. Normally, the inferior rectal nerve originates as a branch of the pudendal nerve. However, during routine dissection, a variant of the inferior rectal nerve was found where it arose directly from the third sacral nerve ventral ramus (S3). Many cases have described the inferior rectal nerve arising independently from the sacral plexus, most commonly from the fourth sacral nerve root (S4); however, few cases have reported the inferior rectal nerve arising from S3. Herein, we describe a variant of the inferior rectal nerve in which the nerve arises independently from the sacral plexus.

KEYWORDS:

Anal canal; Inferior rectal nerve variations; Perineum; Pudendal nerve block

Fig. 1

A variant of the inferior rectal nerve. Note the S3 ventral ramus giving off pelvic splanchnics and then continuing as the inferior rectal nerve. The inferior rectal nerve also gives off a branch to communicate with the pudendal nerve.