The clitoris is a sexual organ located at the front of the vulva, and its primary function is providing pleasure. What most people recognize as “the clitoris” is actually just a small external tip. The full organ extends several centimeters inside the body, with internal structures that surround the vaginal canal and become engorged with blood during arousal.
More Than What You Can See
The visible part of the clitoris, called the glans, is the small nub at the top of the vulva where the inner lips meet. It’s roughly 3 to 5 millimeters across and about 5 millimeters long on average, though size varies from person to person. This is what most people mean when they refer to the clitoris, but it represents only a fraction of the full structure.
Beneath the surface, the clitoris has a body that extends downward and then branches into two legs called crura. These legs, the longest parts of the organ, spread out in a wishbone shape and wrap around the vaginal canal and urethra. There are also two bulbs of spongy tissue nestled between the legs and the vaginal wall. When you include all of these internal components, the total length of the clitoris averages about 16 millimeters, and the whole structure is sometimes described as boomerang-shaped.
For most of medical history, anatomy textbooks depicted the clitoris as a flat, simple structure. That changed in 1998 when Australian urologist Helen O’Connell used MRI scans to map the organ in living tissue for the first time. Her work revealed that the bulbs, crura, and surrounding tissues form an interconnected cluster that can’t be captured in a single diagram. The clitoris, the lower urethra, and the vaginal wall are all intimately connected, and this tissue cluster appears to be central to female orgasm.
How It Develops Before Birth
Early in fetal development, all embryos have the same starting structure: a small mound of tissue called the genital tubercle. This tissue is capable of becoming either a penis or a clitoris. In the presence of androgens (hormones like testosterone), it develops into a penis with a tubular urethra. Without that hormonal signal, the same tissue forms a clitoris. This is why the two organs share so many features. Both contain spongy erectile tissue, both have a glans at the tip, and both become engorged with blood during arousal. The key structural difference is that the clitoris does not contain a urethral tube.
Nerve Supply and Sensitivity
The clitoris is one of the most nerve-dense structures in the human body. A 2023 histological study counted approximately 10,280 nerve fibers reaching the glans clitoris, arriving through paired dorsal nerves (one on each side). This density of nerve fibers packed into such a small area is what makes the glans so sensitive to touch. For comparison, this count is higher than earlier estimates that had circulated in popular science for decades, which were based on animal studies rather than direct measurement of human tissue.
What Happens During Arousal
The clitoris is made of erectile tissue, the same type found in the penis. During sexual arousal, signals from the nervous system cause the smooth muscle in the clitoral tissue to relax, allowing blood to rush in. The internal bulbs can double in size as they fill with blood. Blood flow to the glans increases as well, causing it to swell and become more sensitive. This process of engorgement is part of a broader response that also includes increased vaginal lubrication and lengthening of the vaginal canal.
The arousal response is not purely physical. It involves a combination of mental factors like thoughts and fantasies, non-genital responses like changes in skin blood flow, and the genital engorgement itself. All three work together, which is why arousal can be influenced by psychological state, stress, and physical health.
Its Role in Orgasm
The clitoris is the primary source of orgasm for most women. Research on sexual experience during intercourse found that only 21 to 30 percent of women reported orgasm from penetration alone, without any additional clitoral contact. When clitoral stimulation was deliberately included during intercourse, that number roughly doubled to 51 to 60 percent. These findings reflect what sex researchers have understood for decades: for the majority of women, direct or indirect clitoral stimulation is not a bonus but a central part of reaching orgasm.
The internal parts of the clitoris also play a role. Because the crura and bulbs surround the vaginal canal, penetration can indirectly stimulate these deeper structures. This helps explain why some positions or types of movement feel more pleasurable than others, and why the old distinction between “clitoral” and “vaginal” orgasms is misleading. The clitoris is involved in both.
How It Changes With Age
Like other tissues in the body, the clitoris changes over time. Studies comparing tissue samples from women in their twenties and thirties with those from women over sixty found significant shifts in composition. Collagen content nearly doubled in the older group (from about 24 percent to 46 percent), while smooth muscle and elastic fibers decreased. Since smooth muscle is the tissue that relaxes to allow blood flow during arousal, this increase in stiffer collagen tissue can reduce engorgement and sensitivity.
Hormonal changes during menopause accelerate these shifts. Lower estrogen levels are associated with reduced blood flow to the clitoris. Research has shown that hormone replacement therapy can increase deep clitoral artery blood flow, which may help maintain sensitivity. These age-related changes can contribute to decreased sexual response, but they are gradual, and many women continue to experience clitoral pleasure well into later life.