Perineal hernia

Perineum in humans
The muscles of the male perineum
The muscles of the female perineum
Anatomical terminology []

Perineal hernia is a hernia involving the perineum (pelvic floor). The hernia may contain fluid, fat, any part of the intestine, the rectum, or the bladder. It is known to occur in humans, dogs, and other mammals, and often appears as a sudden swelling to one side (sometimes both sides) of the anus.

A common cause of perineal hernia is surgery involving the perineum. Perineal hernia can be caused also by excessive straining to defecate (tenesmus). Other causes include prostate or urinary disease, constipation, anal sac disease (in dogs), and diarrhea. Atrophy of the levator ani muscle and disease of the pudendal nerve may also contribute to a perineal hernia.

In humans, a major cause of perineal hernia is perineal surgery without adequate reconstruction. In some cases, particularly surgeries to remove the coccyx and distal sacrum, adequate reconstruction is very difficult to achieve. The posterior perineum is a preferred point of access for surgery in the pelvic cavity, particularly in the presacral space. Surgeries here include repair of rectal prolapse and anterior meningocele, radical perineal prostatectomy, removal of tumors including sacrococcygeal teratoma, and coccygectomy. Perineal hernia is a common complication of coccygectomy in adults, but not in infants and children (see coccygectomy).