Tunica albuginea (penis)

Tunica albuginea (penis)
Transverse section of the penis.
The penis in transverse section with tunica albuginea shown.
Details
Identifiers
Latin	tunica albuginea corporum cavernosorum, tunica albuginea corporis spongiosi
TA	A09.4.01.017 A09.4.01.018
FMA	19630
Anatomical terminology []

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. The majority of the remaining tissue is collagen, which is made up of lysine, proline, glycine, alanine, and other amino acids.

The tunica albuginea is directly involved in maintaining an erection; that is due to Buck's fascia constricting the deep dorsal vein of the penis, preventing blood from leaving and thus sustaining the erect state.

The trabeculae of the tunica albuginea are more delicate, nearly uniform in size, and the meshes between them smaller than in the corpora cavernosa penis: their long diameters, for the most part, corresponding with that of the penis.

The external envelope or outer coat of the corpus spongiosum is formed partly of unstriped muscular fibers, and a layer of the same tissue immediately surrounds the canal of the urethra.

The penis in transverse section, showing the blood vessels.

This article incorporates text in the public domain from page 1250 of the 20th edition of Gray's Anatomy (1918)