The Anatomy of the Perineum and Related Conditions

The anterior of the perineum is formed by the urogenital triangle. In men, this region contains the scrotum and penis, and in women, the labia, vagina, and urethra. The area is covered by the perineal membrane, a thin sheet of fascia that divides the region into deep and superficial pouches.

The anal triangle forms the posterior half of the perineum. In both men and women, this region contains the opening of the anus, anal sphincter, and the pudendal nerve, the main nerve supply to the perineum. Fat and connective tissue in the ischioanal fossae on either side of the anus allow for expansion during bowel movements.

The perineum often tears during natural childbirth. There are several degrees of tearing. First-degree tears involve the first layer of tissue; second-degree tears are most common and extend a little deeper. Third-degree tears extend from the vagina through the perineum to the anus, and fourth-degree extends further into the anal sphincter and rectum.

To avoid tearing the perineum, doctors used to regularly perform episiotomies. An episiotomy is a controlled cut in the perineum that allows for an easier birth with less trauma. This was a widely used technique until 2006 when it was no longer recommended — the procedure sometimes causes more problems than slight tearing. However, episiotomies are still used selectively based on clinical judgment.

Injuries can cause pain in the perineum. These types of injuries can happen suddenly due to trauma, falls, burns, or straddle or implement injuries. Chronic injury can also develop from pressure placed on the area for an extended period, such as from cycling long distances. People who work in construction, perform gymnastics, or ride bikes, motorcycles, or horses are more likely to experience perineal injury.

Prostatitis is a common problem for men under 50, and one of the symptoms is pain in the perineum. Acute prostatitis is caused by a bacterial infection and can come on suddenly or develop slowly. Chronic prostatitis may be related to chemicals in the urine, but the exact cause is unknown.

The pelvic floor sits above the perineum and supports the pelvic organs. When the muscles in the pelvic floor become too tight, pain can result. The muscles then become weak, which may affect the ability to pass stool and maintain urinary continence. Pelvic floor dysfunction is common during or after pregnancy, especially after an episiotomy.

Pudendal neuralgia is chronic pain in the perineal area that is worsened by sitting. It affects both genders and can occur in children with anomalies in the nerve pathway. The pudendal nerve is also involved in bladder, bowel, and sexual function and can lead to incontinence and other issues. Pain can be severe, and it usually takes years to get a diagnosis.

For women, another cause of pain in the perineum is vulvodynia. The most common symptom is pain during intercourse, and some women report perineal hypersensitivity to touch, even clothing. There are bladder symptoms, too, including increased urgency and frequency and difficulty urinating. Normal activities, like walking and sitting, can also be difficult.

Interstitial cystitis is a chronic condition that can cause pain and pressure in the bladder and pelvis. This condition affects women more than men and causes an urge to urinate even when the bladder only contains a small amount of urine. The condition can have a significant impact on a person's quality of life.