Anococcygeal raphe

Last revised by Yoshi Yu on 5 Apr 2023

The anococcygeal raphe (plural: anococcygeal raphes or raphae), also known as the anococcygeal ligament or anococcygeal body refers to the midline structure that connects the anorectal junction to the coccyx. It is composed of bilateral interdigitating fibers from the iliococcygeal and pubococcygeal muscles.

The anococcygeal raphe is a thin, linear structure running from the coccyx to the anal canal measuring approximately 1-2 cm in length and 2-5 mm in width 1. It represents the junction of the endopelvic fascia and the levator ani muscles. The anococcygeal raphe can be seen on plain radiographs, CT or MRI. However, it is best seen on axial imaging at the level of the lower border of the pubic symphysis.

The anococcygeal raphe is also known by many other names depending on the author of the paper in the literature and includes the anococcygeal ligament, coccygeal muscular raphe, levator raphe, dorsal layer of the anococcygeal ligament, and raphe of iliococcygeus muscle and pubococcygeus muscle 2.

The connective tissue fibers of the anococcygeal raphe are derived from the pubococcygeal and iliococcygeal muscles bilaterally inserting into the coccyx 3.

The anococcygeal raphe is of clinical significance as it contributes to maintaining the anatomical position of the anorectum in relation to the coccyx and the integrity of the pelvic floor muscles. This facilitates defecation and maintains continence and sexual function 2,4.

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