The clitoris is a sexual organ located at the front of the vulva, and its primary function is pleasure. It contains roughly 10,280 nerve fibers, making it the most sensitive structure in the human body. While most people picture just the small, visible tip, the clitoris is largely an internal organ with erectile tissue that extends several centimeters into the body.
External and Internal Structure
The part you can see is called the glans. It sits at the top of the vulva, just above the urethral opening, and is the only external portion of the clitoris. The glans is small, averaging about 5 millimeters long and 3.4 millimeters wide, though size varies from person to person. A fold of skin called the clitoral hood covers and protects the glans, similar to how foreskin covers the head of the penis. Beneath the hood, a band of tissue called the collar wraps around the base of the glans, helping anchor it in place.
Below the surface, the clitoris is much larger. The total structure, including the glans and the shaft (called the body), averages about 16 millimeters in length, but that measurement only accounts for the midline. Two wing-shaped extensions called crura branch downward and backward from the body, straddling the vaginal canal on either side. Paired bulbs of spongy erectile tissue sit alongside the vaginal opening. Together, the crura and bulbs give the internal clitoris a wishbone-like shape that can span 9 to 11 centimeters.
The glans itself is densely packed with nerve endings but is not erectile tissue. Every other part of the clitoris, the body, crura, and bulbs, is composed of erectile tissue that swells with blood during arousal.
How the Clitoris Responds During Arousal
The clitoris becomes erect through the same basic mechanism as a penis. During arousal, the smooth muscle inside the erectile tissue relaxes, allowing blood to flow in and pool. The spongy tissue swells and firms up. This process is driven by a signaling molecule called nitric oxide, which triggers muscle relaxation in the blood vessel walls and erectile tissue. Estrogen supports this process by boosting nitric oxide production.
The blood supply comes from the internal pudendal artery, the same artery that supplies genital blood flow in all sexes. It branches into a clitoral artery that meets its counterpart from the opposite side just behind the pubic bone before feeding into the clitoris. When arousal ends, the smooth muscle contracts again, pushing blood back out and returning the clitoris to its resting state. The sympathetic nervous system drives this contraction through the release of noradrenaline.
Because the erectile tissue extends well beyond the visible glans, arousal involves swelling throughout the internal structure. The bulbs flanking the vaginal canal engorge, which contributes to the feeling of fullness and increased sensitivity during sexual activity.
Nerve Supply and Sensitivity
A 2023 histological study counted approximately 10,280 myelinated nerve fibers in the dorsal nerve of the clitoris, which is the primary nerve supplying the glans. The glans concentrates these nerve endings into a very small area, which is why it is extraordinarily sensitive to touch, pressure, and vibration.
The dorsal nerves travel along the top of the clitoral body, just beneath the surface, and branch out as they approach the glans and hood. This anatomy matters practically: the area is vulnerable to injury during certain surgical procedures, and the high nerve density explains why direct, firm contact with the glans can feel uncomfortable or even painful for many people. Indirect stimulation through the hood or surrounding tissue is often preferred.
Embryological Origin
The clitoris and the penis develop from the same embryonic structure, called the genital tubercle. For the first several weeks of fetal development, the external genitalia look identical regardless of chromosomal sex. Around the eighth week, hormonal signals begin to differentiate the tissue. In the presence of higher androgen levels, the genital tubercle elongates into a penis and the surrounding folds fuse to form the scrotum. With lower androgen levels, the tubercle becomes the clitoris and the folds remain open, forming the labia.
This shared origin means the clitoris and penis are biological counterparts, or homologues. The glans of the clitoris corresponds to the glans of the penis. The crura and erectile bodies of the clitoris correspond to the corpora cavernosa of the penis. The vestibular bulbs correspond to the spongy tissue surrounding the urethra in the penis. The tissue composition, nerve wiring, and arousal mechanisms are fundamentally parallel.
Why the Full Anatomy Was Overlooked
For most of medical history, anatomy textbooks depicted the clitoris as little more than its visible tip. The internal erectile structures were either mislabeled as separate structures or left out entirely. It was not until detailed dissection and imaging work in the late 1990s and early 2000s that researchers formally established that the bulbs are part of the clitoris, that the crura are substantial paired structures, and that the organ as a whole is far larger than previously taught. This updated anatomical picture, showing the clitoris as an interconnected system of erectile tissue surrounding the vaginal canal, reshaped the understanding of female sexual response.
The practical implication is significant. Because the clitoris wraps around the vaginal opening internally, stimulation of the vaginal walls during penetration can indirectly stimulate clitoral tissue. What was historically described as a separate “vaginal orgasm” likely involves the internal clitoris. The organ is central to sexual pleasure regardless of the type of stimulation involved.
Normal Variation
Clitoral size varies widely. In one study of healthy women, glans width ranged from about 2 to 5 millimeters, and total clitoral length (glans plus body) ranged from roughly 12 to 20 millimeters. These are averages with broad normal ranges, and size does not correlate with sensitivity or sexual function in a straightforward way.
The clitoral hood also varies. In some people it fully covers the glans, in others it retracts partially or sits higher. Tissue between the hood and glans can sometimes form adhesions, where the collar of tissue beneath the hood sticks to the glans. This can trap debris, cause irritation, or reduce sensation. These adhesions are common and generally manageable with gentle care, though persistent pain or changes in sensitivity are worth discussing with a healthcare provider familiar with vulvar anatomy.