The clitoris is the primary organ of sexual pleasure in people with vulvas. Its sole known function is to provide sensory feedback during sexual arousal, making it the only organ in the human body dedicated entirely to generating pleasurable sensation. While small on the surface, most of the clitoris is internal, and its role in sexual response is far more complex than its external appearance suggests.
How the Clitoris Is Built
What you can see from the outside, the small rounded tip called the glans, is only a fraction of the full structure. The glans averages about 6.5 millimeters long and 5.3 millimeters wide, roughly the size of a pea, though this varies widely from person to person. Beneath the surface, the clitoris extends considerably further. It includes a shaft (the body), two legs called crura that anchor to the pelvic bones, and two bulbs of spongy tissue that flank the vaginal opening. Together, these internal and external parts form a wishbone-shaped structure several inches in total length.
The clitoris and the penis develop from the same embryonic tissue, called the genital tubercle. During the first weeks of fetal development, this tissue is identical regardless of sex. Hormonal signals then direct it down different paths. This shared origin explains why the two organs have similar erectile tissue and nerve supply, even though they end up looking and functioning quite differently.
Why It’s So Sensitive
A 2022 study from Oregon Health and Science University counted the nerve fibers in the human clitoral glans for the first time using modern tissue analysis. The researchers found over 10,000 nerve fibers in the dorsal nerve of the clitoris alone, and noted the true total is higher because smaller nerves also feed into the organ. That figure is about 20% more than the commonly cited estimate of 8,000, which was likely based on animal studies rather than human tissue.
This density of nerve endings is packed into a very small area, which is why the glans is extraordinarily sensitive to touch, pressure, and vibration. No other structure of comparable size in the human body contains this concentration of sensory nerves.
What Happens During Arousal
During sexual arousal, the nervous system triggers a cascade of changes in genital blood flow. Nerve endings in the tissue release signaling molecules that relax the smooth muscle inside blood vessel walls, widening them and allowing blood to rush in. At the same time, the drainage of blood out of the area slows. This combination causes the erectile tissue of the clitoris (the body, crura, and bulbs) to swell and stiffen, much like an erection in a penis.
This engorgement increases the sensitivity of the glans and presses the surrounding bulbs against the walls of the vaginal canal. The process also contributes to lubrication: as blood pressure builds in the vaginal walls, fluid passes through the tissue and collects on the vaginal surface. So while the clitoris itself doesn’t produce lubrication, the arousal response it’s part of directly drives it.
Its Role in Orgasm
The clitoris is central to orgasm for most people who have one. In a large study of 749 women, 94% reported that clitoral stimulation could lead to orgasm. About 70% said deep vaginal stimulation could also produce orgasm, and 64% reported that their usual path to orgasm involved both clitoral and vaginal stimulation together. In a separate lab-based study where 26 women masturbated to orgasm, every single participant used clitoral stimulation as their primary method.
These numbers reflect what anatomists have long observed: the glans sits outside the vaginal canal, which means penetrative intercourse alone often doesn’t provide enough direct contact with it. This isn’t a design flaw. Evolutionary biologists at Yale have proposed that the clitoris was originally positioned inside the reproductive tract in ancestral mammals, where stimulation during mating triggered a hormonal reflex that caused ovulation. As some species, including humans, evolved to ovulate on a regular cycle instead, the clitoris shifted to its current external position. Freed from its role in reproduction, it retained and refined its role in pleasure.
How Hormones Affect Clitoral Function
The clitoris depends on a steady hormonal environment to function well. Both estrogen and testosterone play distinct roles in maintaining its tissue. Estrogen supports the contractile machinery of clitoral smooth muscle and helps sustain blood flow to the broader pelvic region. Testosterone, meanwhile, supports the relaxation side of the equation, helping blood vessels in clitoral tissue dilate properly during arousal through a pathway involving nitric oxide.
This is why menopause, which sharply reduces estrogen and gradually lowers testosterone, can affect clitoral sensitivity and arousal. Reduced pelvic blood flow leads to tissue changes including vaginal dryness and, in some cases, decreased clitoral responsiveness. Research in postmenopausal women has shown that testosterone therapy, alone or combined with other hormone replacement, significantly improves multiple aspects of sexual function, including arousal. Both hormones appear necessary to keep the clitoris’s vascular and nerve responses working as they should.
Conditions That Affect the Clitoris
Because the glans is covered by a fold of skin called the clitoral hood, the two can sometimes become fused together. This condition, called clitoral phimosis, occurs when scar tissue or adhesions prevent the hood from retracting normally. It shows up in roughly 23% of women who seek care for sexual dysfunction. Symptoms include itching, burning, pain during sex, and reduced or absent clitoral sensation, which can lead to difficulty reaching orgasm.
Mild cases are typically managed with topical corticosteroids to reduce inflammation, but once scarring has formed between the hood and the glans, it doesn’t reverse on its own. In more advanced cases, a minor surgical procedure can separate the adhesions and restore normal movement of the hood over the glans. Trapped secretions beneath fused tissue can also form small cysts, adding to discomfort. The key diagnostic step is straightforward: checking whether the hood moves freely over the glans during a physical exam.
Why Full Anatomy Wasn’t Mapped Until 2005
Despite centuries of anatomical study, the internal structure of the clitoris wasn’t comprehensively described until Australian urologist Helen O’Connell published detailed dissection and MRI-based research. Her landmark 2005 paper used magnetic resonance imaging on living volunteers to map each component of the clitoris, revealing the full extent of the bulbs, crura, and their relationship to surrounding structures. Previous anatomical textbooks had either minimized or outright omitted the internal portions. O’Connell’s work established that the bulbs of spongy tissue flanking the vagina are part of the clitoris, not separate structures, and that the organ as a whole is significantly larger than medical literature had acknowledged for over a century.