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.