Buttocks

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: 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 analogous anatomical structures known as ischial callosities allow primates to sit upright without resting their weight on their feet as four-legged animals do. The pads enable the monkeys to sleep sitting upright on thin branches, beyond reach of predators, without falling. Humans do not possess ischial callosities due to the gluteal muscles being large enough to provide the same cushioning. Females of certain species of baboon have red callosities 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.

Some baboons and all gibbons, though otherwise fur-covered, have characteristic naked ischial callosities on their rears. 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 , classical pronunciation nătes ) which is plural; the singular, natis (buttock), is rarely used. There are many colloquial terms for them.

Gallery of art

File:Boxer or Apollo Side.jpg|Prominent, muscular buttocks are a standard feature of athletic and military artwork from Ancient Greece, as demonstrated by this statue of a boxer. British Museum () File:The Motya Charioteer, made by a Greek sculptor in Sicily, about 460-450 BC, found in 1979 on the Sicilian island of Motya (Mozia), Winning at the ancient Games, British Museum (7642744838).jpg|The Motya Charioteer, from Ancient Greece (–450 BC) File:Studio Jean Jacques Lequeu.jpg|Jean-Jacques Lequeu () File:Odalisque.jpg|Jules Lefebvre () File:Étude de fesses.jpg|Félix Vallotton () File:Georges Seurat - A Sunday on La Grande Jatte -- 1884 - Google Art Project.jpg|Georges Seurat's 1884 painting A Sunday Afternoon on the Island of La Grande Jatte depicts a woman on the right with a prominent bustle under her dress.

Gallery

File:Stage Door Johnnies.jpg|A burlesque stage show with three men in Las Vegas Image:Fremont naked cyclists 2007 - 59.jpg|Seattle's nudist cyclists with painted buttocks Image:Japanese traditional swimwear FUNDOSHI red rokushaku back photomodel fthong 1.jpg|A Japanese man in traditional Fundoshi-rokushaku swimwear File:Posterior view of human female and male, without labels.jpg|Posterior view of human female and male to show the comparison of their buttocks File:Bikini girls Holland beach 1999.jpg|Some female clothing, such as the bikini or panties, show part of the female buttocks (woman on left). Thongs, in particular, leave almost all of the buttocks exposed (woman on right). Photo is of a beach in Holland, 1999. File:D6B 1320 - Got Ass? Girls (12079087053).jpg|Models participate in "got ass?", a competition to judge the woman with best buttocks, at AVN Adult Entertainment Expo, Las Vegas, 2014.

References

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". Souvenir.
3. (22 March 1894). "Police.". The Times.
4. Montagu, Ashley. (3 October 1966). "The Buttocks and Natural Selection". JAMA.
5. Foundations of Osteopathic Medicine, Page 586, Anthony G. Chila – 2010
6. Recent Advances in Pediatrics, 2013 Suraj Gupte, p 141
7. "Nates Definitions & Meanings {{!}} Dictionary.com".
8. A New Dictionary of the Latin and English Languages, published Ward, Lock & Co., London, 1908