Tunica albuginea (penis)

The fibrous envelope of the corpus cavernosum urethræ (or tunica albuginea) is thinner, whiter in color, and more elastic than that of the corpora cavernosa penis.

The trabeculæ 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 cavernosum urethræ is formed partly of unstriped muscular fibers, and a layer of the same tissue immediately surrounds the canal of the urethra.