The clitoris is a small cylinder about 2 to 3 cm (about ³/₄ inch to slightly more than 1 inch) long, containing two small erectile bodies (the corpora cavernosa). In the female fetus, the corpora cavernosa begin as separate entities, but later in fetal development they unite at the midline to form the clitoris proper. During sexual excitement, the corpora cavernosa become engorged with blood, causing erection. The body of the clitoris is suspended from the pubic bone by a short ligament and emerges to form the tiny glans at the top of the vulva (q.v.). This glans has a generous supply of sensitive nerve endings, which account for the clitoris' central role in tactile sexual stimulation.