Anococcygeal raphe

The anococcygeal raphe refers to the midline structure composed of connective tissue fibres that connectconnects the anorectal junction to the coccyx by the interdigitation. It is composed of bilateral interdigitating fibres from the iliococcygeal fibres and pubococcygeal fibres bilaterallymuscles.

The anococcygeal raphe is seen as 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. However, it is best seen on axial imaging at the level of the lower border of the pubic symphysis.

Terminology

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.

Gross Anatomy

Origin

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

Clinical Importance

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, and therefore, facilitating. This facilitates defaecation and maintainingmaintains continence and sexual function ^2,4.