Clitoral erection is a physiological phenomenon where the

clitoris The clitoris ( or ) is a female sex organ present in mammals, ostriches and a limited number of other animals. In humans, the visible portion – the glans – is at the front junction of the labia minora (inner lips), above the op ...

becomes enlarged and firm. Clitoral erection is the result of a complex interaction of psychological, neural, vascular, and endocrine factors, and is usually, though not exclusively, associated with

sexual arousal Sexual arousal (also known as sexual excitement) describes the physiological and psychological responses in preparation for sexual intercourse or when exposed to sexual stimuli. A number of physiological responses occur in the body and mind a ...

. Erections should eventually subside, and the prolonged state of clitoral erection even while not aroused is a condition that could become painful. This swelling and shrinking to a relaxed state seems linked to

nitric oxide Nitric oxide (nitrogen oxide or nitrogen monoxide) is a colorless gas with the formula . It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its ...

's effects on tissues in the clitoris, similar to its role in penile erection.

Physiology

The clitoris is the homologue of the

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males d ...

in the female. Similarly, the clitoris and the erection of it can subtly differ in size. The visible part of the clitoris, the

glans clitoridis The glans (, plural "glandes" ; from the Latin word for "acorn") is a vascular structure located at the tip of the penis in male mammals or a homologous genital structure of the clitoris in female mammals. Structure The exterior structure of ...

, varies in size from a few millimeters to one centimeter and is located at the front junction of the

labia minora The labia minora (Latin for 'smaller lips', singular: ''labium minus'', 'smaller lip'), also known as the inner labia, inner lips, vaginal lips or nymphae are two flaps of skin on either side of the human vaginal opening in the vulva, situated b ...

(inner lips), above the opening of the

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra ...

. It is covered by the

clitoral hood In the female human body, the clitoral hood (also called preputium clitoridis and clitoral prepuce) is a fold of skin that surrounds and protects the glans of the clitoris; it also covers the external shaft of the clitoris, develops as part of th ...

. Any type of motion can increase

blood flow Hemodynamics or haemodynamics are the dynamics of blood flow. The circulatory system is controlled by homeostatic mechanisms of autoregulation, just as hydraulic circuits are controlled by control systems. The hemodynamic response continuously m ...

to this organ and this results in increased secretions which lubricate the

vagina In mammals, the vagina is the elastic, muscular part of the female genital tract. In humans, it extends from the vestibule to the cervix. The outer vaginal opening is normally partly covered by a thin layer of mucosal tissue called the hymen ...

. There are many ways to stimulate the clitoris. Clitoral erection occurs when the corpora cavernosa, two expandable

erectile Erectile tissue is tissue in the body with numerous vascular spaces, or cavernous tissue, that may become engorged with blood. However, tissue that is devoid of or otherwise lacking erectile tissue (such as the labia minora, the vestibule/vagina a ...

structures, become engorged with blood. This may result from any of various

physiological Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemica ...

stimuli, including

. During sexual arousal, arterial blood flow to the clitoris is increased, and trabecular

smooth muscle Smooth muscle is an involuntary non- striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit ...

within the clitoris relaxes allowing blood to engorge the erectile tissues. The ischiocavernosus and

bulbospongiosus muscle The bulbospongiosus muscle (bulbocavernosus in older texts) is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis. In fema ...

s contract to compress the dorsal vein of the clitoris to stop drainage of the clitoris, trapping the blood. More specifically, the clitoris has two adjoining erectile tissues corpus cavernosa (corpus cavernosa clitoridis) that form a main body that connects to the glans clitoridis. There is also a strip of erectile tissue (similar to the placement of the corpus spongiosum in males) running along the ventral surface of the corpus cavernosa main body that connects the glans clitoridis to the commissure of the vestibular bulbs. The main body of the corpus cavernosa with a ventral erectile tissue strip make up the shaft, which is connected to the glans clitoridis. The tunica albuginea is a fibrous-elastic sheath, surrounds the shaft and glans clitoridis. The tunica albuginea does not surround the bulbs of vestibule. The erectile tissues are composed of endothelium-lined vascular spaces in a trabecular matrix, with the

endothelium The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the ve ...

-lined vascular spaces surrounded by smooth muscle capable of contraction and relaxation. During sexual arousal, arterial blood flow to the clitoris is increased, and within the clitoris, the arteries further branch to supply the erectile tissues. The trabecular smooth muscles of the erectile tissue relax increasing blood flow to fill the vascular spaces, expanding the erectile tissues until they are fully engorged with blood. The ischiocavernosus and bulbocavernosus muscles contract, compressing the dorsal vein of the clitoris. This compression of the vein restricts drainage of the erectile structures, trapping the blood. This process stretches the tunica albuginea. As a result, the clitoris becomes tumescent to accommodate the increased intracavernosus pressure. The tunica albuginea of the clitoris is made up of one layer making it more elastic than the tunica albuginea of the penis, which is composed of two layers. Erick Janssen (2007) elaborates on this reporting that "the corpora cavernosa of the clitoris are essentially similar to that of the penis except that there is no subalbugineal layer interposed between the tunica albuginea and the erectile tissue. In the penis, this tissue engorges with blood during sexual arousal and becomes compressed against the unyielding tunica, creating penile rigidity --a true erection. The lack of this plexus in the clitoris indicates that while the organ can become tumescent or engorged, it cannot, like the penis, become stiffly erect. The clitoris thus does not really become erect with sexual excitement, but engorged." In addition, the tunica albuginea around the glans is thinner than around the shaft in both the clitoris and penis. This gives the glans less firmness relative to the shaft. The extrusion of the glans clitoridis and thinning of the skin enhances sensitivity to physical contact. After a female has

orgasm Orgasm (from Greek , ; "excitement, swelling") or sexual climax is the sudden discharge of accumulated sexual excitement during the sexual response cycle, resulting in rhythmic, involuntary muscular contractions in the pelvic region chara ...

ed, the erection usually ends, but this may take time.

Medical Conditions

Clitoral priapism

Priapism, while more common in males, is a condition that can also effect the clitoris. Symptoms include painful engorgement of the clitoris, swelling of the clitoris, and pain in the area around the clitoris.

In non-human animals

Among capuchin monkeys, clitoral erection is possible and makes the clitoris more visible than in its relaxed state where it is hidden by a preputial fold.Carosi, M, Spani, F, Ulland, AE, Scalici, M, Suomi, SJ. Clitoral length in immature and mature captive tufted capuchin (''Sapajus'' spp.) females: A cross-sectional study. ''Am J Primatol''. 2020; 82:e23135. https://doi.org/10.1002/ajp.23135

Notes

References