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The hard palate is a thin horizontal bony plate made up of two bones of the
facial skeleton The facial skeleton comprises the ''facial bones'' that may attach to build a portion of the skull. The remainder of the skull is the braincase. In human anatomy and development, the facial skeleton is sometimes called the ''membranous visceroc ...
, located in the roof of the mouth. The bones are the palatine process of the maxilla and the
horizontal plate of palatine bone The horizontal plate of palatine bone is a quadrilateral part of the palatine bone, 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. The infe ...
. The hard palate spans the alveolar arch formed by the
alveolar process The alveolar process () or alveolar bone is the thickened ridge of bone that contains the tooth sockets on the jaw bones (in humans, the maxilla and the mandible). The structures are covered by gums as part of the oral cavity. The synonymous ...
that holds the upper
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, ...
(when these are developed).


Structure

The hard palate is formed by the palatine process of the maxilla and
horizontal plate of palatine bone The horizontal plate of palatine bone is a quadrilateral part of the palatine bone, 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. The infe ...
. It forms a partition between the nasal passages and the
mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...
. On the anterior portion of the hard palate are the plicae, irregular ridges in the mucous membrane that help facilitate the movement of food backward towards the larynx. This partition is continued deeper into the mouth by a fleshy extension called the
soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammals, the soft tissue constituting the back of the roof of the mouth. The soft palate is part of the palate of the mouth; the other part is the hard palat ...
. On the ventral surface of hard palate, some projections or transverse ridges are present which are called as palatine rugae.


Function

The hard palate is important for feeding and speech. Mammals with a defective hard palate may die shortly after birth due to inability to suckle. It is also involved in
mastication Chewing or mastication is the process by which food is crushed and ground by teeth. It is the first step of digestion, and it increases the surface area of foods to allow a more efficient break down by enzymes. During the mastication process, ...
in many species. The interaction between the
tongue The tongue is a muscular organ in the mouth of a typical tetrapod. It manipulates food for mastication and swallowing as part of the digestive process, and is the primary organ of taste. The tongue's upper surface (dorsum) is covered by taste ...
and the hard palate is essential in the formation of certain
speech Speech is a human vocal communication using language. Each language uses phonetic combinations of vowel and consonant sounds that form the sound of its words (that is, all English words sound different from all French words, even if they are th ...
sounds, notably high-front vowels,
palatal consonant Palatals are consonants articulated with the body of the tongue raised against the hard palate (the middle part of the roof of the mouth). Consonants with the tip of the tongue curled back against the palate are called retroflex. Characteris ...
s, and
retroflex consonant A retroflex ( /ˈɹɛtʃɹoːflɛks/), apico-domal ( /əpɪkoːˈdɔmɪnəl/), or cacuminal () consonant is a coronal consonant where the tongue has a flat, concave, or even curled shape, and is articulated between the alveolar ridge and the h ...
s such as like "see", like "yes", (realization of /hj/ in English) like "hue", and (/r/, only for some speakers) like "red".


Clinical significance


Cleft palate

In the
birth defect A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...
called cleft palate, the left and right portions of this plate are not joined, forming a gap between the mouth and nasal passage (a related defect affecting the face is cleft lip). While a cleft palate has a severe impact upon the ability to
nurse Nursing is a profession within the health care sector focused on the care of individuals, families, and communities so they may attain, maintain, or recover optimal health and quality of life. Nurses may be differentiated from other health ...
and speak, it is now successfully treated through reconstructive surgical procedures at an early age. This is the time where such procedures are available. Due to the complexity of this birth defect, researchers still do not know exactly what causes the cleft palate to form during foetal development. Recently, these researchers found that even though there is no exact cause, there are several factors that drastically increase the risk of a baby being born with an orofacial cleft palate. As for the environmental risk factors, maternal smoking is the most influential risk factor. Based on a recent study of 103 German patients with cleft palates, it was found that 25.2% of their mothers smoked during pregnancy, a higher proportion than for the population as a whole. While maternal smoking during pregnancy is a risk, there are also several genetic risk factors. Six single-nucleotide polymorphisms in the PAX7 gene are implicated in the development of facial features. These variations occur at six loci: 1p36, 2p21, 3p11.1, 8q21.3, 13q31.1 and 15q22. When tested in the European and Asian communities, five of the six loci had a significant association at the 95% confidence level. Besides the PAX 7 gene variants, there were also five possible mutations found in the transforming growth factor-alpha gene (''TGFA'') that could lead to the development of a cleft palate. Even though several risk factors have been linked to cleft palates, more research must be done in order to determine the true causes of the defect.


Palatal abscess

Palatal
abscess An abscess is a collection of pus that has built up within the tissue of the body. Signs and symptoms of abscesses include redness, pain, warmth, and swelling. The swelling may feel fluid-filled when pressed. The area of redness often extends ...
es may also occur.


Hard palate pigmentation

Long-term use of the drug chloroquine diphosphatase, used in malaria prophylaxis,
rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are inv ...
and other conditions, was found to cause bluish-grey pigmentation in the hard palate.


See also

* Electropalatograph *
Head and neck anatomy This article describes the anatomy of the head and neck of the human body, including the brain, bones, muscles, blood vessels, nerves, glands, nose, mouth, teeth, tongue, and throat. Structure Bones The head rests on the top part of the vertebra ...
*
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 ...
* Palate *
Soft palate The soft palate (also known as the velum, palatal velum, or muscular palate) is, in mammals, the soft tissue constituting the back of the roof of the mouth. The soft palate is part of the palate of the mouth; the other part is the hard palat ...


References

{{DEFAULTSORT:Hard Palate Palate palate Speech organs ja:口蓋#硬口蓋