Clitoral erection is a physiological phenomenon where the clitoris 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.
The clitoris is the homologue of the penis in the female. The part visible on the outside varies in size from a few millimeters to one centimeter and is located hidden in the upper labial fold. Any type of motion can increase blood flow to this organ and this results in increased secretions which lubricate the vagina. There are many ways to stimulate the clitoris.
Clitoral erection occurs when the corpora cavernosa, two expandable erectile structures, become engorged with blood. This may result from any of various physiological stimuli, including sexual arousal. During sexual arousal, arterial blood flow to the clitoris is increased, and trabecular smooth muscle within the clitoris relaxes allowing blood to engorge the erectile tissues. The ischiocavernous and bulbocavernous muscles contract to compress the dorsal vein of the clitoris to stop drainage of the clitoris, trapping the blood. More specifically, the clitoris has 2 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 canervosa main body that connects the glans clitoridis to the commissure of the vestibular bulbs. The main body of the corpus canervosa with a ventral erectile tissue strip make up the shaft, which is connected to the glans clitoridis. The tunica albuginea, 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-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 ischiocavernous and bulbocavernous 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 intracavernous 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 canervosa 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 orgasmed, the erection usually ends, but this may take time.
Signs of clitoral stimulation
Stimulation of the clitoris can lead to vaginal wetness and engorgement and swelling of the clitoris and the labia, along with increased redness or darkening of the skin in these areas. Further sexual arousal can lead to changes to the internal organs, including to the internal shape of the vagina and to the position of the uterus within the pelvis. Other changes include an increase in heart rate as well as in blood pressure, feeling hot and flushed and perhaps experiencing tremors. A sex flush may extend over the chest and upper body. If sexual stimulation continues, then sexual arousal may peak into orgasm.
Shape and size
An erect clitoris can take on a number of different shapes and angles, ranging from small and embedded, to large and protruding. Generally, the size of an erect clitoris is fixed throughout post-pubescent life.
Neurovascular mechanism of clitoral erection
The clitoris consists of an external short head attached to a long body which is internally located. The body of the clitoris is surrounded by bulky erectile tissue on either side. This bulk contains muscles and is richly innervated with sensory nerves. While the penis is an external organ which is distended, the clitoris is small and is an internal structure. The major nerve which produces sensations to the clitoris is a branch of the pudendal nerve, also known as the dorsal nerve of the clitoris.
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