The external male organ of urination and copulation. Its structure varies a great deal between the species. In carnivores and horses the bulk of the organ is erectile tissue; in cats and dogs there is a bone included in the glans. In cats the penis is directed backwards (retromingent). In ruminants and pigs the bulk of the penis is connective tissue and the organ is long and firm and has a large sigmoid flexure which disappears when the penis is in the erect state. In rams and goat bucks the penile urethra is continued beyond the glans as the urethral process. See also penile.
- corkscrew p. — see corkscrew penis.
- corpus cavernosum p. — one of the two bodies that make up the dorsal compartment of erectile tissue, grooved below to carry the corpus spongiosum penis (syn. corpus cavernosum urethrae). It arises from each side of the ischial arch as the crus penis and at its anterior end is enclosed by the glans which is an extension of the corpus spongiosum.
- corpus spongiosum p. — a column of erectile tissue around the urethra of the penis and extending into the glans penis.
- short p. — an uncommon, possibly inherited, defect in some breeds of cattle.
- supernumerary p. — a rare deformity, usually ectopic.
- p. urethral process detached — the free end of the penis has a bifid structure.
