Smegma (

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...

σμῆγμα : ''smēgma'') is a combination of shed skin cells, skin oils, and moisture. It occurs in both male and female mammalian genitalia. In females, it collects around the clitoris and in the folds 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 ...

; in males, smegma collects under the

foreskin In male human anatomy, the foreskin, also known as the prepuce, is the double-layered fold of skin, mucosal and muscular tissue at the distal end of the human penis that covers the glans and the urinary meatus. The foreskin is attached to the ...

Females

The accumulation of sebum combined with dead skin cells forms smegma. ''Smegma clitoridis'' is defined as the secretion of the

apocrine glands Apocrine () glands are a type of exocrine gland, which are themselves a type of gland, i.e. a group of cells specialized for the release of secretions. Exocrine glands secrete by one of three means: holocrine, merocrine and apocrine. In apocri ...

of the clitoris, in combination with desquamating epithelial cells. Glands that are located around the clitoris, the labia minora, and the labia majora secrete sebum. If smegma is not removed frequently it can lead to clitoral adhesion which can make clitoral stimulation (such as masturbation) painful (clitorodynia).

Males

In males, smegma helps keep the

glans 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 ...

moist and facilitates sexual intercourse by acting as a lubricant. Smegma, itself, is completely benign, but uncircumcised "men with

phimosis Phimosis (from Greek φίμωσις ''phimōsis'' 'muzzling'.) is a condition in which the foreskin of the penis cannot stretch to allow it to be pulled back past the glans. A balloon-like swelling under the foreskin may occur with urination. In ...

have an increased risk of penile cancer." Smegma was originally thought to be produced by

sebaceous gland A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest nu ...

s near the

frenulum A frenulum (or frenum, plural: frenula or frena, from the Latin ''frēnulum'', "little bridle", the diminutive of ''frēnum'') is a small fold of tissue that secures the motion of a mobile organ in the body. In human anatomy Frenula on the h ...

called Tyson's glands; however, subsequent studies have failed to find these glands. Joyce Wright states that smegma is produced from minute microscopic protrusions of the mucosal surface of the foreskin and that living cells constantly grow towards the surface, undergo fatty degeneration, separate off, and form smegma. Parkash ''et al.'' found that smegma contains 26.6% fats and 13.3% proteins, which they judged to be consistent with necrotic epithelial debris. Newly produced smegma has a smooth, moist texture. It is thought to be rich in

squalene Squalene is an organic compound. It is a triterpenoid with the formula C30H50. It is a colourless oil, although impure samples appear yellow. It was originally obtained from shark liver oil (hence its name, as ''Squalus'' is a genus of sharks). A ...

and contain prostatic and seminal secretions, desquamated epithelial cells, and the mucin content of the urethral glands of Littré. Smegma contains

cathepsin B Cathepsin B belongs to a family of lysosomal cysteine proteases known as the cysteine cathepsins and plays an important role in intracellular proteolysis. In humans, cathepsin B is encoded by the ''CTSB'' gene. Cathepsin B is upregulated in ce ...

, lysozymes, chymotrypsin, neutrophil elastase and cytokines, which aid the immune system. According to Wright, little smegma is produced during childhood, although the foreskin may contain sebaceous glands. She also says that production of smegma increases from adolescence until sexual maturity when the function of smegma for lubrication assumes its full value, and from middle-age production starts to decline and in old age virtually no smegma is produced. Jakob Øster reported that the incidence of smegma increased from 1% among 6- to 7-year-olds and 8- to 9-year-olds to 8% among 14- to 15-year-olds and 16- to 17-year-olds (an overall incidence of 5%). There is no evidence that smegma, itself, causes penile cancer, but it may harbor cancerous pathogens, like HPV, and its presence over a long period of time may irritate and inflame the penis, which may increase the risk of cancer. It may also make it harder to see very early cancers.

Other animals

In healthy animals, smegma helps clean and lubricate the genitals. In veterinary medicine, analysis of this smegma is sometimes used for detection of urogenital tract pathogens, such as '' Tritrichomonas foetus''. Accumulation of smegma in the equine preputial folds and the urethral fossa and urethral diverticulum can form large "beans" and promote the carriage of '' Taylorella equigenitalis'', the causative agent of

contagious equine metritis Contagious equine metritis (CEM) is a type of metritis (uterine inflammation) in horses that is caused by a sexually transmitted infection. It is thus an equine venereal disease of the genital tract of horses, brought on by the '' Taylorella equig ...

. Some equine veterinarians have recommended periodic cleaning of male genitals to improve the health of the animal.

References

External links

* * * {{cite book , doi=10.1007/978-3-030-37621-5_17 , chapter=Smegma , title=Normal and Abnormal Prepuce , year=2020 , last1=Fahmy , first1=Mohamed A. Baky , pages=153–161 , isbn=978-3-030-37620-8 , s2cid=243171662 Excretion Exocrine system Mammal female reproductive system Mammal male reproductive system

Females

Males

Other animals

See also

References

External links