A cusp is a pointed, projecting, or elevated feature. In

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

s, it is usually used to refer to raised points on the crowns of

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, t ...

. The concept is also used with regard to the leaflets of the four

heart valve A heart valve is a one-way valve that allows blood to flow in one direction through the chambers of the heart. Four valves are usually present in a mammalian heart and together they determine the pathway of blood flow through the heart. A heart v ...

s. The

mitral valve The mitral valve (), also known as the bicuspid valve or left atrioventricular valve, is one of the four heart valves. It has two cusps or flaps and lies between the left atrium and the left ventricle of the heart. The heart valves are all one-w ...

, which has two cusps, is also known as the bicuspid valve, and the

tricuspid valve The tricuspid valve, or right atrioventricular valve, is on the right dorsal side of the mammalian heart, at the superior portion of the right ventricle. The function of the valve is to allow blood to flow from the right atrium to the right vent ...

has three cusps.

In humans

A cusp is an occlusal or incisal eminence on a tooth. Canine teeth, otherwise known as cuspids, each possess a single cusp, while

premolar The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...

s, otherwise known as bicuspids, possess two each. Molars normally possess either four or five cusps. In certain populations the

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

ry molars, especially

first molar The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

s, will possess a fifth cusp situated on the mesiolingual cusp known as the

Cusp of Carabelli The cusp of Carabelli, or Carabelli's tubercle, or ''tuberculum anomale'' of Georg Carabelli is a small additional cusp at the mesiopalatal line angle of maxillary first molars. This extra cusp is usually found on the secondary maxillary first m ...

. Buccal Cusp- One other variation of the upper first premolar is the 'Uto-Aztecan' upper premolar. It is a bulge on the buccal cusp that is only found in Native American Indians, with highest frequencies of occurrence in Arizona. The name is not a dental term; it comes from a regional linguistic division of Native American Indian language groups. Buccal-The side of a tooth that is adjacent to (or the direction towards) the inside of the cheek, as opposed to lingual or palatal, which refer to the side of a tooth adjacent to (or the direction towards) the tongue or palate, respectively. Although technically referring only to posterior teeth (where the cheeks are present instead of lips, use of this term may extend to all teeth, anterior and posterior), this term may be employed to describe the facial surface of (or directions in relation to) anterior teeth as well.

Cusps on the molars of therian mammals

There are 4 main cusps found on the

molars The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...

of the upper dentition of

theria Theria (; Greek: , wild beast) is a subclass of mammals amongst the Theriiformes. Theria includes the eutherians (including the placental mammals) and the metatherians (including the marsupials) but excludes the egg-laying monotremes. ...

n mammals.

Hypocone

The ''hypocone'' is found on the distal lingual side of the tooth. It fits into the grooves of the lower dentition and is an

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

for the overall grinding and tearing of foods using the occlusal (chewing side) of the tooth surface during

occlusion Occlusion may refer to: Health and fitness * Occlusion (dentistry), the manner in which the upper and lower teeth come together when the mouth is closed * Occlusion miliaria, a skin condition * Occlusive dressing, an air- and water-tight trauma ...

or mastication (chewing). Its strength is due to the thickness of the enamel which differs among species of hominids. The hypocone appears to have evolved independently more than twenty times in different mammal groups during the Cenozoic period.

Metacone

The ''metacone'' is a

cusp A cusp is the most pointed end of a curve. It often refers to cusp (anatomy), a pointed structure on a tooth. Cusp or CUSP may also refer to: Mathematics * Cusp (singularity), a singular point of a curve * Cusp catastrophe, a branch of bifurc ...

on the

of the upper dentition in

hominids The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the ...

. It is found at the buccal

distal Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

area of the tooth. The crests between the cusps are

adaptations In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the ...

for slicing food during

or mastication (chewing).

Paracone

The anterior of the three cusps of a primitive upper molar that in higher forms is the principal anterior and outside cusp.

Protocone

The ''protocone'' is founding the

of the upper dentition in

Placental Placental mammals (infraclass Placentalia ) are one of the three extant subdivisions of the class Mammalia, the other two being Monotremata and Marsupialia. Placentalia contains the vast majority of extant mammals, which are partly distinguishe ...

and

Marsupial Marsupials are any members of the mammalian infraclass Marsupialia. All extant marsupials are endemic to Australasia, Wallacea and the Americas. A distinctive characteristic common to most of these species is that the young are carried in a ...

vertebrates.Gavin Prideaux, "Systematics and Evolution of the Sthenurine Kangaroos" (April 1, 2004). UC Publications in Geological Sciences. Paper vol_146. http://repositories.cdlib.org/ucpress/ucpgs/vol_146 p.16 It is found at the mesiolingual area of the tooth. The crests between the cusps are