Urinary meatus

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Urinary meatus
Illu penis.jpg
Urinary meatus in the penis
Details
Identifiers
Latin Orificium urethrae externum
Anatomical terminology

The urinary meatus,[1] also known as the external urethral orifice, is the opening or meatus of the urethra. It is the point where urine exits the urethra in males and in females, and also where semen exits the urethra in males. The meatus has varying degrees of sensitivity to touch. The meatus is located on the glans penis in males and in the vulval vestibule in females.

In human males[edit]

Drawing of the male internal sexual anatomy
Meatus of a penis

The male external urethral orifice is the external opening or urinary meatus, normally located at the tip of the glans penis, at its junction with the frenular delta. It presents as a vertical slit, possibly bounded on either side by two small labia-like projections and continues longitudinally along the front aspect of the glans, which facilitates the flow of urine micturition. In some cases the opening may be more rounded and this can occur naturally or may also occur as a side effect of excessive skin removal during circumcision. The meatus is a sensitive part of the male reproductive system.

Meatal stenosis is a late complication of circumcision, which occurs in about 10-20 percent of newborn circumcised boys after the loss of the protection of the foreskin.[2]

Due to the flexibility of the penis and meatus, the stream of urine in the male can be manipulated and targeted. In different cultures different positions of urination are employed. Sitting and squatting are also options to standing to urinate. Also in the elderly male with prostate problems sitting down is preferable.[3][4] For practising Muslim men, the genital modesty of squatting is also associated with proper cleanliness requirements or awrah.[5]

In human females[edit]

Lateral anatomy view of the female reproductive system

The female external urethral orifice is the external opening of the urethra, from which urine is ejected during urination. It is located about 2.5 cm behind the clitoris and immediately in front of the vagina in the vulval vestibule. It usually assumes the form of a short, sagittal cleft with slightly raised margins. To its left and right are the openings of the Skene's glands.

Some evidence exists to suggest that the clitoral-urinary meatus distance (CUMD) in human females relates to the ease with which she may achieve orgasm through penetrative sex. Orgasm from penetration alone is observed to be more likely as CUMD decreases.[6]

In other mammals[edit]

Unlike most other mammals, female spotted hyenas have a urinary meatus that is located on the clitoral glans.[7][8]

Clinical significance[edit]

Congenital disorders of the meatus, in the male, include epispadias – the misplacement to the upper aspect and hypospadias – the misplacement to the underside of the penis. A congenital misshaping can result in its narrowing (meatal stenosis) causing a partial or total urinary blockage, or the bifurcation of the urinary stream. A urethral blockage can also be caused by foreign material, kidney or bladder stones (lithiasis).

See also[edit]

References[edit]

  1. ^ Meatus refers to a tubular opening or passage in the body. From Latin meātus: a course, passing.
  2. ^ Sorokan SK, Finlay JC, Jefferies A. Newborn male circumcision. Paediatr Child Health. 2015;20(6):311–15. PMID 26435672. PMC 4578472.
  3. ^ de Jong, Y; Pinckaers, JH; Ten Brinck, RM; Lycklama À Nijeholt, AA; Dekkers, OM (2014). "Urinating Standing versus Sitting: Position Is of Influence in Men with Prostate Enlargement. A Systematic Review and Meta-Analysis". PLOS ONE. 9 (7): e101320. doi:10.1371/journal.pone.0101320. PMC 4106761Freely accessible. PMID 25051345. 
  4. ^ Y. de Jong. "Influence of voiding posture on urodynamic parameters in men: a literature review" (PDF). Nederlands Tijdschrift voor urologie). Retrieved 2014-07-02. 
  5. ^ Mustafa Umar. "Standing up and urinating in Islam". Iman Suhaib Webb (USA). Archived from the original on 2013-05-30. Retrieved 2013-06-11. 
  6. ^ Wallen, Kim; Lloyd, Elisabeth A. (2017-03-13). "Female Sexual Arousal: Genital Anatomy and Orgasm in Intercourse". Hormones and Behavior. 59 (5): 780–792. doi:10.1016/j.yhbeh.2010.12.004. ISSN 0018-506X. PMC 3894744Freely accessible. PMID 21195073. 
  7. ^ Cunha, Gerald R., et al. "Development of the external genitalia: perspectives from the spotted hyena (Crocuta crocuta)." Differentiation 87.1 (2014): 4-22.
  8. ^ Drea, C. M., et al. "Exposure to naturally circulating androgens during foetal life incurs direct reproductive costs in female spotted hyenas, but is prerequisite for male mating." Proceedings of the Royal Society of London B: Biological Sciences 269.1504 (2002): 1981-1987.