A histotopographic study of the perineal body in elderly women: the surgical applicability of novel histological findings

Female perineal structures located around the perineal body were histologically examined using semiserial sections obtained from 15 elderly female cadavers. The smooth muscle content of the perineal body was greater in multiparous women. The connective tissue of the perineal body extended inferolaterally and provided a fibromuscular mass that was 10–30 mm long mediolaterally and 3–15 mm long superoinferiorly. The lateral extension (LEX) of the perineal body occupies a space that is surrounded by the vestibular bulb, internal anal sphincter, and levator ani slings. The LEX did not directly connect to the ischiopubic bony rami but did connect indirectly via the vestibular bulb and ischiocavernosus. Thus, the LEX appears to play a critical role for maintaining the topographical relationship between the vagina and the rectum. The surgical approximation of bilateral LEX instead of levator ani may be of key importance when doing a perineorrhaphy. As pudendal nerve branches run along the inferior margin of the LEX, a mediolateral episiotomy may not be the best option.