Palatine bone
Encyclopedia
The palatine bone is a bone
in many species of the animal kingdom, commonly termed the palatum (Latin palatum; unrelated to palatium 'palace', from which other senses of palatine
derive).
between the maxilla
and the pterygoid process of the sphenoid
.
It contributes to the walls of three cavities: the floor and lateral wall of the nasal cavity, the roof of the mouth, and the floor of the orbit; it enters into the formation of two fossæ, the pterygopalatine
and pterygoid
fossæ; and one fissure, the inferior orbital fissure
.
The palatine bone somewhat resembles the letter L, and consists of a Horizontal plate of palatine bone
and a Perpendicular plate of palatine bone
and three outstanding processes—viz., the Pyramidal process of palatine bone
, which is directed backward and lateralward from the junction of the two parts, and the Orbital process of palatine bone
and Sphenoidal process of palatine bone
, which surmount the vertical part, and are separated by a deep notch, the sphenopalatine notch.
The human palatine articulates with six bones: the sphenoid
, ethmoid, maxilla
, inferior nasal concha, vomer
and opposite palatine.
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
s, the palatine bone is reduced in most living amphibian
s, forming, in frog
s and salamander
s, only a narrow bar between the vomer and maxilla.
Early fossil reptile
s retained the arrangement seen in more primitive vertebrates, but in mammal
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
development has occurred to varying degrees in many living reptiles, reaching its greatest extent in crocodilians. In bird
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.
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
in many species of the animal kingdom, commonly termed the palatum (Latin palatum; unrelated to palatium 'palace', from which other senses of palatine
Palatine
A palatine or palatinus is a high-level official attached to imperial or royal courts in Europe since Roman times...
derive).
Human anatomy
It is situated at the back part of the nasal cavityNasal cavity
The nasal cavity is a large air filled space above and behind the nose in the middle of the face.- Function :The nasal cavity conditions the air to be received by the other areas of the respiratory tract...
between the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
and the pterygoid process of the sphenoid
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
.
It contributes to the walls of three cavities: the floor and lateral wall of the nasal cavity, the roof of the mouth, and the floor of the orbit; it enters into the formation of two fossæ, the pterygopalatine
Pterygopalatine fossa
The pterygopalatine fossa is a fossa in the skull. It is the indented area medial to the pterygomaxillary fissure leading into the sphenopalatine foramen.-Boundaries:It has the following boundaries:...
and pterygoid
Pterygoid
Pterygoid can refer to:* Pterygoid processes of the sphenoid bone** The Lateral pterygoid plate by it* a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle* a branch of the Mandibular nerve...
fossæ; and one fissure, the inferior orbital fissure
Inferior orbital fissure
Not to be confused with the infraorbital groove, infraorbital canal, and infraorbital foramen.The lateral wall and the floor of the orbit are separated posteriorly by the inferior orbital fissure which transmits the maxillary nerve and its zygomatic branch, and the ascending branches from the...
.
The palatine bone somewhat resembles the letter L, and consists of a Horizontal plate of palatine bone
Horizontal plate of palatine bone
The horizontal part of the palatine bone is quadrilateral, and has two surfaces and four borders.- Surfaces :The superior surface, concave from side to side, forms the back part of the floor of the nasal cavity....
and a Perpendicular plate of palatine bone
Perpendicular plate of palatine bone
The vertical part of the palatine bone is thin, of an oblong form, and presents two surfaces and four borders.- Surfaces :...
and three outstanding processes—viz., the Pyramidal process of palatine bone
Pyramidal process of palatine bone
The pyramidal process of the palatine bone projects backward and lateralward from the junction of the horizontal and vertical parts, and is received into the angular interval between the lower extremities of the pterygoid plates....
, which is directed backward and lateralward from the junction of the two parts, and the Orbital process of palatine bone
Orbital process of palatine bone
The orbital process of the palatine bone is placed on a higher level than the sphenoidal, and is directed upward and lateralward from the front of the vertical part, to which it is connected by a constricted neck. It presents five surfaces, which enclose an air cell...
and Sphenoidal process of palatine bone
Sphenoidal process of palatine bone
The sphenoidal process of the palatine bone is a thin, compressed plate, much smaller than the orbital, and directed upward and medialward.It presents three surfaces and two borders....
, which surmount the vertical part, and are separated by a deep notch, the sphenopalatine notch.
The human palatine articulates with six bones: the sphenoid
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
, ethmoid, maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
, inferior nasal concha, vomer
Vomer
The vomer 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 maxillary bones.-Biology:...
and opposite palatine.
In other animals
In bony fishOsteichthyes
Osteichthyes , also called bony fish, are a taxonomic group of fish that have bony, as opposed to cartilaginous, skeletons. The vast majority of fish are osteichthyes, which is an extremely diverse and abundant group consisting of over 29,000 species...
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
Tetrapod
Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...
s, the palatine bone is reduced in most living amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s, forming, in frog
Frog
Frogs are amphibians in the order Anura , formerly referred to as Salientia . Most frogs are characterized by a short body, webbed digits , protruding eyes and the absence of a tail...
s and salamander
Salamander
Salamander is a common name of approximately 500 species of amphibians. They are typically characterized by a superficially lizard-like appearance, with their slender bodies, short noses, and long tails. All known fossils and extinct species fall under the order Caudata, while sometimes the extant...
s, only a narrow bar between the vomer and maxilla.
Early fossil reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
s retained the arrangement seen in more primitive vertebrates, but in mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
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
Hard palate
The hard palate is a thin horizontal bony plate of the skull, located in the roof of the mouth. It spans the arch formed by the upper teeth.It is formed by the palatine process of the maxilla and horizontal plate of palatine bone....
, separating the oral and nasal cavities, and making it easier to breathe while eating. A parallel
Parallel evolution
Parallel evolution is the development of a similar trait in related, but distinct, species descending from the same ancestor, but from different clades.-Parallel vs...
development has occurred to varying degrees in many living reptiles, reaching its greatest extent in crocodilians. In bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
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
Rough-skinned Newt
The rough-skinned newt is a North American newt known for its strong poison.- Toxicity :Many newts produce toxins to avoid predation, but the toxins of the genus Taricha are particularly potent...
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.
See also
- Bone terminology
- Terms for anatomical location