Tunica albuginea
Tunica albuginea
Thick elastic membrane inside the penis that helps keep it stiff during an erection.
The tunica albuginea is a thick, strong sheath within the penis that helps maintain the penis stiff during an erection. It surrounds the cavernous bodies (the structures that fill with blood during an erection) and is made up mainly of collagen, a strong protein found throughout the body.
The tunica albuginea has two layers. The inner layer wraps around the erectile tissue in a circular pattern. The outer layer runs lengthwise from the head of the penis to the base. This structure provides support and helps the penis maintain its shape during an erection.
Sometimes, scar tissue may form on the tunica albuginea, creating a hard area called a plaque or fibrous penile plaque (hard tissue). This plaque pulls on the surrounding tissues and causes the penis to curve or bend. When this leads to pain and discomfort, the condition is known as Peyronie’s disease.