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The body of the penis consists of three cylindrical-shaped masses of erectile tissue which run the length of the penis. Two of the masses lie alongside each other and end behind the head of the penis. The third mass lies underneath them. This latter mass contains the urethra. The penis terminates in an oval or cone-shaped body, the glans penis, which contains the exterior opening of the urethra.
The glans penis is covered by a loose skin, the foreskin or prepuce, which enables it to expand freely during erection. The skin ends just behind the glans penis and folds forward to cover it. The inner surface of the foreskin contains glands that secrete a lubricating fluid called smegma which makes it easy for the penis to expand and retract past the foreskin.
web·bed pe·nis(webd pēnis)
penis(pe'nis) plural.penises, penes [L.]
The penis is composed mainly of erectile tissue arranged in three columns, the whole being covered with skin. The two lateral columns are the corpora cavernosa penis. The third or median column, known as the corpus spongiosum, contains the urethra. The body is attached to the descending portion of the pubic bone by the crura of the penis. The cone-shaped head of the penis, the glans penis, contains the urethral orifice. It is covered with a movable hood known as the foreskin or prepuce, under which is secreted the substance called smegma.
Hyperemia of the genitals fills the corpora cavernosa with blood as the result of sexual excitement or stimulation, thus causing an erection. The hyperemia subsides following orgasm and ejaculation of the seminal fluid. The organ then returns to its flaccid condition. The size of the flaccid penis does not necessarily correlate with that of the erect penis.
The occult location of the organ can interfere with normal urination and with sexual penetration.