William Aiken

Although the human penis has no bone, it may 'fracture' during an erection if subjected to a sudden bending force.

In western society, this catastrophic, but uncommon injury, most commonly occurs during aggressive intercourse in which the erect penis accidentally slips out of the vagina and is struck with force against the woman's pubic bone, thigh, buttocks or perineum (area between the vagina and anus).

It may occur in any coital position but happens frequently during woman- on-top intercourse in which the full weight and momentum of the female partner comes down on the penis, which has slipped out of the vagina, causing it to snap or fracture. At the time of injury, a loud cracking noise is typically heard followed by immediate pain and loss of erection then subsequent swelling and deformity of the penis.

There is often significant ignorance, embarrassment and shame surrounding this injury and, sometimes patients are not with their wives or regular partners at the time of injury, causing further stress and anxiety. As a consequence patients may delay seeking medical attention, doing so only after concluding that they are not getting better without medical help.

Not a real fracture

A penile fracture is not a true fracture in the usual sense as there is no bone to be broken but is instead the medical jargon used to denote the injury described above. To understand what happens during a penile fracture some knowledge of penile anatomy is essential.

The human penis is composed of three longitudinally (along the length) placed cylindrical chambers of spongy erectile (expands easily with blood) tissue, two dorsally (on top) and one ventrally (beneath) and in the middle. The cylindrical chamber, placed beneath and in the middle, is smaller than the two on top and contains the urine passage or urethra. This is called the corpus spongiosum while the two on top are called the corpora cavernosa.

These chambers are enclosed by elastic fibrous tissue (tunica albuginea) which is able to stretch to accommodate an erection. In the non-erect (flaccid) state, the tunica albuginea is thick and pliable but it becomes stretched, tense and thinned during an erection. Outside of the tunica albuginea are other layers of tissue coverings through which travel some of the nerves and blood vessels of the penis and the skin of the penis surrounds all of these.

What happens

During an erection blood is trapped under very high pressure in the corpora which causes them to expand maximally and the tunica albuginea becomes tense, stretched and thinned. If the penis is subjected to a sudden bending force the pressure inside rises even higher until the tunica albuginea snaps at its weakest point and the contained blood rushes out into the tissues of the penis to cause immediate loss of erection and swelling and deformity of the penis.

In 10 to 20 per cent of cases the urethra is partially or completely torn across. At the University Hospital of the West Indies (UHWI), we have seen one case in which all three chambers were completely transected or torn during rear entry vaginal intercourse.

If left untreated penile fractures may be complicated by the development of erectile dysfunction, abnormal curvature of the penis (Peyronie's disease), painful fibrous nodules, urethral stricture and other complications.

Penile fractures are usually diagnosed on the basis of history and examination findings alone. Occasionally, it may be difficult to differentiate a bona fide case from torn superficial penile veins and, in these cases, an MRI scan can help make the distinction.

Immediate surgical repair of these injuries results in an excellent functional and cosmetic outcome and a lower incidence of complications.

Dr. William Aiken is the head of Urology at the University Hospital of the West Indies and President of the Jamaica Urological Society; email: yourhealth@gleanerjm.com.