Buttocks

From Wikipedia the free encyclopedia

Buttocks
Buttocks of a human female (upper) and a human male (lower)
Details
ArterySuperior gluteal artery, inferior gluteal artery
NerveSuperior gluteal nerve, inferior gluteal nerve, superior cluneal nerves, medial cluneal nerves, inferior cluneal nerves
Identifiers
Latinclunis
MeSHD002081
TA98A01.1.00.033
A01.2.08.002
TA2157
FMA76446
Anatomical terminology

The buttocks (sg.: buttock) are two rounded portions of the exterior anatomy of most mammals, located on the posterior of the pelvic region. In humans, the buttocks are located between the lower back and the perineum. They are composed of a layer of exterior skin and underlying subcutaneous fat superimposed on a left and right gluteus maximus and gluteus medius muscles. The two gluteus maximus muscles are the largest muscles in the human body. They are responsible for movements such as straightening the body into the upright (standing) posture when it is bent at the waist; maintaining the body in the upright posture by keeping the hip joints extended; and propelling the body forward via further leg (hip) extension when walking or running.[1]

In many cultures, the buttocks play a role in sexual attraction.[2] Many cultures have also used the buttocks as a primary target for corporal punishment,[3] as the buttocks' layer of subcutaneous fat offers protection against injury while still allowing for the infliction of pain.

Structure

The buttocks are formed by the masses of the gluteal muscles or "glutes" (the gluteus maximus muscle and the gluteus medius muscle) superimposed by a layer of fat. The superior aspect of the buttock ends at the iliac crest, and the lower aspect is outlined by the horizontal gluteal crease. The gluteus maximus has two insertion points: 13 superior portion of the linea aspera of the femur, and the superior portion of the iliotibial tractus. The masses of the gluteus maximus muscle are separated by an intermediate intergluteal cleft or "crack" in which the anus is situated.

The buttocks allow primates to sit upright without resting their weight on their feet as four-legged animals do. Females of certain species of baboon have red buttocks that blush to attract males. In the case of humans, females tend to have proportionally wider and thicker buttocks due to higher subcutaneous fat and proportionally wider hips. In humans they also have a role in propelling the body in a forward motion and aiding bowel movement.[4][5]

Some baboons and all gibbons, though otherwise fur-covered, have characteristic naked callosities on their buttocks. While human children generally have smooth buttocks, mature males and females have varying degrees of hair growth, as on other parts of their body. Females may have hair growth in the gluteal cleft (including around the anus), sometimes extending laterally onto the lower aspect of the cheeks. Males may have hair growth over some or all of the buttocks.

Names

The Latin name for the buttocks is nates (English pronunciation /ˈntz/ NAY-teez,[6] classical pronunciation nătes [ˈnateːs][7]) which is plural; the singular, natis (buttock), is rarely used. There are many colloquial terms for them.

See also

References

  1. ^ Norman Eizenberg et al., General Anatomy: Principles and Applications (2008), p. 17.
  2. ^ Hennig, Jean-Luc (1995). The rear view: A brief and elegant history of bottoms through the ages. London: Souvenir. ISBN 0-285-63303-1.
  3. ^ "Police". The Times. London. 22 March 1894. Archived from the original on 1 July 2014. Retrieved 5 December 2010. Mr. Curtis Bennett deprecated caning on the hands and boxing the ears, and said they were exceedingly dangerous forms of punishment. Nature provided a special place for boys to be punished upon and it should be used.
  4. ^ Foundations of Osteopathic Medicine, Page 586, Anthony G. Chila – 2010
  5. ^ Recent Advances in Pediatrics, 2013 Suraj Gupte, p 141
  6. ^ "Nates Definitions & Meanings | Dictionary.com". www.dictionary.com. Retrieved 10 June 2022.
  7. ^ A New Dictionary of the Latin and English Languages, published Ward, Lock & Co., London, 1908