What is the penis?

What it is

• The penis is a pendulous organ suspended from the front and sides of the pubic arch and containing the greater part of the urethra. In the flaccid condition it is cylindrical in shape, but when erect assumes the form of a triangular prism with rounded angles, one side of the prism forming the dorsum. It is composed of three cylindrical masses of cavernous tissue bound together by fibrous tissue and covered with skin.
• Two of the masses are lateral, and are known as the corpora cavernosa penis; the third is median, and is termed the corpus cavernosum urethræ . The Corpora Cavernosa Penis form the greater part of the substance of the penis. For their anterior three-fourths they lie in intimate apposition with one another, but behind they diverge in the form of two tapering processes, known as the crura, which are firmly connected to the rami of the pubic arch.
• Traced from behind forward, each crus begins by a blunt-pointed process in front of the tuberosity of the ischium. Just before it meets its fellow it presents a slight enlargement, named by Kobelt the bulb of the corpus cavernosum penis. Beyond this point the crus undergoes a constriction and merges into the corpus cavernosum proper, which retains a uniform diameter to its anterior end. Each corpus cavernosum penis ends abruptly in a rounded extremity some distance from the point of the penis.
• The corpora cavernosa penis are surrounded by a strong fibrous envelope consisting of superficial and deep fibers. The superficial fibers are longitudinal in direction, and form a single tube which encloses both corpora; the deep fibers are arranged circularly around each corpus, and form by their junction in the median plane the septum of the penis.
• This is thick and complete behind, but is imperfect in front, where it consists of a series of vertical bands arranged like the teeth of a comb; it is therefore named the septum pectiniforme.