anatomy Anatomy () is the branch of biology concerned with the study of the structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having i ...

, the palatine bones () are two irregular bones of the facial skeleton in many animal species, located above the

uvula The palatine uvula, usually referred to as simply the uvula, is a conic projection from the back edge of the middle of the soft palate, composed of connective tissue containing a number of racemose glands, and some muscular fibers. It also conta ...

in the throat. Together with the maxillae, they comprise the hard palate. (''Palate'' is derived from the Latin ''palatum''.)

Structure

The palatine bones are situated at the back of the

nasal cavity The nasal cavity is a large, air-filled space above and behind the nose in the middle of the face. The nasal septum divides the cavity into two cavities, also known as fossae. Each cavity is the continuation of one of the two nostrils. The nasal ...

between 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 ...

and the pterygoid 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 the pterygopalatine and pterygoid fossae, and the inferior orbital fissures. Each palatine bone somewhat resembles the letter L, and consists of a horizontal plate, a perpendicular plate, and three projecting processes—the pyramidal process, which is directed backward and lateral from the junction of the two parts, and the orbital and sphenoidal 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. The human palatine articulates with six bones: the sphenoid, ethmoid,

, inferior nasal concha,

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right max ...

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 larger greater 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, the lesser 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.

Function

The sphenopalatine 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 the sphenopalatine artery from the maxillary artery.

Other animals

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartil ...

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 primitive

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...

s, the palatine bone is reduced in most living amphibians, forming, in

frog A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...

s and

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

s, only a narrow bar between the vomer and maxilla. Early fossil

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchocephalia ...

s retained the arrangement seen in more primitive vertebrates, but in

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur ...

s, 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 the hard palate, separating the oral and nasal cavities, and making it easier to breathe while eating. A

parallel Parallel is a geometric term of location which may refer to: Computing * Parallel algorithm * Parallel computing * Parallel metaheuristic * Parallel (software), a UNIX utility for running programs in parallel * Parallel Sysplex, a cluster o ...

development has occurred to varying degrees in many living reptiles, reaching its greatest extent in

crocodilian Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest livin ...

s. In

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

s, the palatine bones remain separate, long the sides of the rear part of the upper jaw, and typically have a mobile articulation with the cranium. There are numerous variations amongst mammals, amphibians and other species. For example, the palatine bone in many amphibians such as the rough-skinned newt manifests as a distinct V-shaped structure. In the case of cat species, the horizontal and a vertical elements join at a forty five degree angle.

Additional images

File:Orbital_bones.png, The seven bones which articulate to form the orbit. File:Gray167.png, Articulation of left palatine bone with maxilla. File:Gray187.png, Base of skull. Inferior surface. File:Gray192.png, Medial wall of left orbit. File:Gray196.png, Roof, floor, and lateral wall of left nasal cavity. File:Gray168.png, Medial aspect of left palatine bone. File:Gray169.png, Posterior aspect of left palatine bone.

References

External links