| Palatine bone | |
|---|---|
 Inferior view of the palatine bones | |
 Animation of the palatine bones | |
| Details | |
| Identifiers | |
| Latin | os palatinum |
| TA98 | A02.1.13.001 |
| TA2 | 798 |
| FMA | 52746 |
| Anatomical terms of bone | |
Inanatomy, thepalatine bones (/ˈpælətaɪn/;[1][2] derived from the Latinpalatum) are twoirregular bones of thefacial skeleton in many animal species, located above theuvula in thethroat. Together with themaxilla, they comprise thehard palate.
The palatine bones are situated at the back of thenasal cavity between themaxilla and thepterygoid process of the sphenoid bone.
They contribute to the walls of three cavities: the floor and lateral walls of the nasal cavity, the roof of the mouth, and the floor of the orbits. They help to form thepterygopalatine andpterygoid fossae, and theinferior orbital fissures.
Each palatine bone somewhat resembles the letter L, and consists of ahorizontal plate, aperpendicular plate, and three projecting processes—thepyramidal process, which is directed backward and lateral from the junction of the two parts, and theorbital andsphenoidal processes, which surmount the vertical part, and are separated by a deep notch, the sphenopalatine notch. The two plates form the posterior part of the hard palate and the floor of the nasal cavity; anteriorly, they join with the maxillae. The two horizontal plates articulate with each other at the posterior part of the median palatine suture and more anteriorly with the maxillae at the transverse palatine suture.[3]
The human palatine articulates with six bones: thesphenoid,ethmoid,maxilla,inferior nasal concha,vomer and opposite palatine.
There are two important foramina in the palatine bones that transmit nerves and blood vessels to this region: the greater and lesser palatine. The largergreater palatine foramen is located in the posterolateral region of each of the palatine bones, usually at the apex of the maxillary third molar. The greater palatine foramen transmits the greater palatine nerve and blood vessels. A smaller opening nearby, thelesser palatine foramen, transmits the lesser palatine nerve and blood vessels to the soft palate and tonsils. Both foramina are openings of the pterygopalatine canal that carries the descending palatine nerves and blood vessels from the pterygopalatine fossa to the palate.[3]
Thesphenopalatine foramen is the opening between the sphenoid bone and orbital processes of the palatine bone; it opens into the nasal cavity and gives passage to branches from the pterygopalatine ganglion and thesphenopalatine artery from the maxillary artery.[3]
Inbony fish, the palatine bone consists of the perpendicular plate only, lying on the inner edge of the maxilla. The lower surface of the bone may bear several teeth, forming a second row behind those of the maxilla; in many cases, these are actually larger than the maxillary teeth. Although a similar pattern was present in primitivetetrapods, the palatine bone is reduced in most livingamphibians, forming, infrogs andsalamanders, only a narrow bar between the vomer and maxilla.[4]
Early fossilreptiles retained the arrangement seen in more primitive vertebrates, but inmammals, the lower surface of the palatine became folded over during evolution, forming the horizontal plate, and meeting in the midline of the mouth. This forms the rear of thehard palate, separating the oral and nasal cavities, and making it easier to breathe while eating. Aparallel development has occurred to varying degrees in many living reptiles, reaching its greatest extent incrocodilians. Inbirds, the palatine bones remain separate, long the sides of the rear part of the upper jaw, and typically have a mobile articulation with thecranium.[4]
There are numerous variations amongst mammals, amphibians and other species. For example, the palatine bone in many amphibians such as therough-skinned newt manifests as a distinct V-shaped structure.[5] In the case of cat species, the horizontal and a vertical elements join at a 45-degree angle.[6]
This article incorporates text in thepublic domain frompage 166 of the 20th edition ofGray's Anatomy(1918)
