A penile fracture is an injury caused by the rupture of the tunica albuginea

Tunica albuginea (penis)

The tunica albuginea is the fibrous envelope of the corpora cavernosa penis. It consists of approximately 5% elastin, an extensible tissue that is primarily made up of the amino acids glycine, valine, alanine, and proline...

, which envelops the corpus cavernosum penis

Corpus cavernosum penis

The corpus cavernosum penis is one of a pair of sponge-like regions of erectile tissue which contain most of the blood in the penis during penile erection...

. It is most often caused by a blunt trauma

Blunt trauma

In medical terminology, blunt trauma, blunt injury, non-penetrating trauma or blunt force trauma refers to a type of physical trauma caused to a body part, either by impact, injury or physical attack; the latter usually being referred to as blunt force trauma...

 to an erect penis

Penis

The penis is a biological feature of male animals including both vertebrates and invertebrates...

.
A popping or cracking sound, significant pain, immediate flaccidity, and skin hematoma

Hematoma

A hematoma, or haematoma, is a localized collection of blood outside the blood vessels, usually in liquid form within the tissue. This distinguishes it from an ecchymosis, which is the spread of blood under the skin in a thin layer, commonly called a bruise...

 of various sizes are commonly associated with the event. These symptoms are similar to a common bruising or contusion of the penis.
Penile fracture is a medical emergency

Medical emergency

A medical emergency is an injury or illness that is acute and poses an immediate risk to a person's life or long term health. These emergencies may require assistance from another person, who should ideally be suitably qualified to do so, although some of these emergencies can be dealt with by the...

, and emergency surgical

Surgery

Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

 repair is the usual treatment.