Human mouth

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Human mouth
Close up man lips.jpg
Photograph of the closed mouth of a human male
Illu01 head neck.jpg
Head and neck
Details
Identifiers
Latin os, cavitas oralis
TA98 A01.1.00.010
TA2 119
Anatomical terminology

In human anatomy, the mouth is the first portion of the alimentary canal that receives food and produces saliva. [1] The oral mucosa is the mucous membrane epithelium lining the inside of the mouth.

Contents

In addition to its primary role as the beginning of the digestive system, the mouth also plays a significant role in communication. While primary aspects of the voice are produced in the throat, the tongue, lips, and jaw are also needed to produce the range of sounds included in speech.

The mouth consists of two regions, the vestibule and the oral cavity proper. The mouth, normally moist, is lined with a mucous membrane, and contains the teeth. The lips mark the transition from mucous membrane to skin, which covers most of the body.

Structure

Oral cavity

Anatomy of the mouth. Blausen 0653 MouthAnatomy.png
Anatomy of the mouth.
Floor of the mouth with lingual frenum and sublingual fold Floor of the mouth.png
Floor of the mouth with lingual frenum and sublingual fold

The mouth consists of two regions: the vestibule and the oral cavity proper. The vestibule is the area between the teeth, lips and cheeks. [2] The oral cavity is bounded at the sides and in front by the alveolar process (containing the teeth) and at the back by the isthmus of the fauces. Its roof is formed by the hard palate. The floor is formed by the mylohyoid muscles and is occupied mainly by the anterior two-thirds of the tongue. A mucous membrane – the oral mucosa, lines the sides and under surface of the tongue to the gums, and lines the inner aspect of the jaw (mandible). It receives secretions from the submandibular and sublingual salivary glands. The posterior border of the oral cavity (ie, junction between the oral cavity and the oropharynx) includes the junction of the hard palate and the soft palate superiorly, the circumvallate papillae of the tongue inferiorly, and the retromolar trigone.

Lips

A closed human mouth. Mouth.jpg
A closed human mouth.

The lips come together to close the opening of the mouth, forming a line between the upper and lower lip. In facial expression, this mouth line is iconically shaped like an up-open parabola in a smile, and like a down-open parabola in a frown. A down-turned mouth means a mouth line forming a down-turned parabola, and when permanent can be normal. Also, a down-turned mouth can be part of the presentation of Prader–Willi syndrome. [3]

Nerve supply

The teeth and the periodontium (the tissues that support the teeth) are innervated by the maxillary and mandibular nerves – divisions of the trigeminal nerve. Maxillary (upper) teeth and their associated periodontal ligament are innervated by the superior alveolar nerves, branches of the maxillary division, termed the posterior superior alveolar nerve, anterior superior alveolar nerve, and the variably present middle superior alveolar nerve. These nerves form the superior dental plexus above the maxillary teeth. The mandibular (lower) teeth and their associated periodontal ligament are innervated by the inferior alveolar nerve, a branch of the mandibular division. This nerve runs inside the mandible, within the inferior alveolar canal below the mandibular teeth, giving off branches to all the lower teeth (inferior dental plexus). [4] [5] The oral mucosa of the gingiva (gums) on the facial (labial) aspect of the maxillary incisors, canines and premolar teeth is innervated by the superior labial branches of the infraorbital nerve. The posterior superior alveolar nerve supplies the gingiva on the facial aspect of the maxillary molar teeth. The gingiva on the palatal aspect of the maxillary teeth is innervated by the greater palatine nerve apart from in the incisor region, where it is the nasopalatine nerve (long sphenopalatine nerve). The gingiva of the lingual aspect of the mandibular teeth is innervated by the sublingual nerve, a branch of the lingual nerve. The gingiva on the facial aspect of the mandibular incisors and canines is innervated by the mental nerve, the continuation of the inferior alveolar nerve emerging from the mental foramen. The gingiva of the buccal (cheek) aspect of the mandibular molar teeth is innervated by the buccal nerve (long buccal nerve). [6]

Development

The philtrum is the vertical depression formed between the philtral ridges between the upper lip and the nasal septum, formed where the nasomedial and maxillary processes meet during embryo development. When these processes fail to fuse fully, a cleft lip, cleft palate, or both can result.

The nasolabial folds are the deep creases of tissue that extend from the nose to the sides of the mouth. One of the first signs of age on the human face is the increase in prominence of the nasolabial folds.

Function

The mouth plays an important role in eating, drinking, and speaking. Mouth breathing refers to the act of breathing through the mouth (as a temporary backup system) if there is an obstruction to breathing through the nose, which is the designated breathing organ for the human body. [7]

Infants are born with a sucking reflex, by which they instinctively know to suck for nourishment using their lips and jaw. The mouth also helps in chewing and biting food.

For some disabled people, especially many disabled artists, who through illness, accident or congenital disability have lost dexterity, their mouths take the place of their hands, when typing, texting, writing, making drawings, paintings and other works of art by maneuvering brushes and other tools, in addition to the basic oral functions. Mouth painters hold the brush in their mouth or between their teeth and maneuver it with their tongue and cheek muscles, but mouth painting can be strenuous for neck and jaw muscles since the head has to perform the same back and forth movement as a hand does when painting. [8] [9]

A male mouth can hold, on average, 71.2 ml (2.51 imp fl oz; 2.41 US fl oz), while a female mouth holds 55.4 ml (1.95 imp fl oz; 1.87 US fl oz). [10]

See also

Further reading

Related Research Articles

<span class="mw-page-title-main">Facial nerve</span> Cranial nerve VII, for the face and tasting

The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue. The nerve typically travels from the pons through the facial canal in the temporal bone and exits the skull at the stylomastoid foramen. It arises from the brainstem from an area posterior to the cranial nerve VI and anterior to cranial nerve VIII.

<span class="mw-page-title-main">Maxilla</span> Upper jaw bone

The maxilla in vertebrates is the upper fixed 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. The two maxillary bones are fused at the intermaxillary suture, forming the anterior nasal spine. This is similar to the mandible, which is also a fusion of two mandibular bones at the mandibular symphysis. The mandible is the movable part of the jaw.

<span class="mw-page-title-main">Soft palate</span> Flexible part of maxilla

The soft 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 palate. The soft palate is distinguished from the hard palate at the front of the mouth in that it does not contain bone.

<span class="mw-page-title-main">Mandibular nerve</span> Branch of the trigeminal nerve responsible for the lower face and jaw

In neuroanatomy, the mandibular nerve (V3) is the largest of the three divisions of the trigeminal nerve, the fifth cranial nerve (CN V). Unlike the other divisions of the trigeminal nerve (ophthalmic nerve, maxillary nerve) which contain only afferent fibers, the mandibular nerve contains both afferent and efferent fibers. These nerve fibers innervate structures of the lower jaw and face, such as the tongue, lower lip, and chin. The mandibular nerve also innervates the muscles of mastication.

<span class="mw-page-title-main">Cheek</span> Facial feature

The cheeks constitute the area of the face below the eyes and between the nose and the left or right ear. "Buccal" means relating to the cheek. In humans, the region is innervated by the buccal nerve. The area between the inside of the cheek and the teeth and gums is called the vestibule or buccal pouch or buccal cavity and forms part of the mouth. In other animals the cheeks may also be referred to as "jowls".

Infiltration analgesia is deposition of an analgesic drug close to the apex of a tooth so that it can diffuse to reach the nerve entering the apical foramina. It is the most routinely used in dental local treatment.

<span class="mw-page-title-main">Pterygopalatine ganglion</span> Parasympathetic ganglion in the pterygopalatine fossa

The pterygopalatine ganglion is a parasympathetic ganglion in the pterygopalatine fossa. It is one of four parasympathetic ganglia of the head and neck,.

The oral mucosa is the mucous membrane lining the inside of the mouth. It comprises stratified squamous epithelium, termed "oral epithelium", and an underlying connective tissue termed lamina propria. The oral cavity has sometimes been described as a mirror that reflects the health of the individual. Changes indicative of disease are seen as alterations in the oral mucosa lining the mouth, which can reveal systemic conditions, such as diabetes or vitamin deficiency, or the local effects of chronic tobacco or alcohol use. The oral mucosa tends to heal faster and with less scar formation compared to the skin. The underlying mechanism remains unknown, but research suggests that extracellular vesicles might be involved.

<span class="mw-page-title-main">Lingual nerve</span> Human nerve relaying sense to the tongue

The lingual nerve carries sensory innervation from the anterior two-thirds of the tongue. It contains fibres from both the mandibular division of the trigeminal nerve (CN V3) and from the facial nerve (CN VII). The fibres from the trigeminal nerve are for touch, pain and temperature (general sensation), and the ones from the facial nerve are for taste (special sensation).

<span class="mw-page-title-main">Inferior alveolar artery</span>

The inferior alveolar artery is an artery of the head. It is a branch of the maxillary artery. It descends through the infratemporal fossa as part of a neurovascular bundle with the inferior alveolar nerve and vein to the mandibular foramen where it enters and passes anterior-ward inside the mandible, suplying the body of mandible and the dental pulp of the lower molar and premolar teeth. Its terminal incisor branch supplies the rest of the lower teeth. Its mental branch exits the mandibula anteriorly through the mental foramen to supply adjacent lip and skin.

<span class="mw-page-title-main">Mental nerve</span> Sensory nerve of the face

The mental nerve is a sensory nerve of the face. It is a branch of the posterior trunk of the inferior alveolar nerve, itself a branch of the mandibular nerve (CN V3), itself a branch of the trigeminal nerve (CN V). It provides sensation to the front of the chin and the lower lip, as well as the gums of the anterior mandibular (lower) teeth. It can be blocked with local anaesthesia for procedures on the chin, lower lip, and mucous membrane of the inner cheek. Problems with the nerve cause chin numbness.

<span class="mw-page-title-main">Nasopalatine nerve</span> Nerve of the head

The nasopalatine nerve (also long sphenopalatine nerve) is a nerve of the head. It is a sensory branch of the maxillary nerve (CN V2) that passes through the pterygopalatine ganglion (without synapsing) and then through the sphenopalatine foramen to enter the nasal cavity, and finally out of the nasal cavity through the incisive canal and then the incisive fossa to enter the hard palate. It provides sensory innervation to the posteroinferior part of the nasal septum, and gingiva just posterior to the upper incisor teeth.

<span class="mw-page-title-main">Anterior superior alveolar nerve</span>

The anterior superior alveolar nerve (or anterior superior dental nerve) is a branch of the infraorbital nerve (itself a branch of the maxillary nerve (CN V2)). It passes through the canalis sinuosus to reach and innervate upper front teeth. Through its nasal branch, it also innervates parts of the nasal cavity.

<span class="mw-page-title-main">Head and neck anatomy</span>

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.

Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. Tooth formation begins before birth, and the teeth's eventual morphology is dictated during this time. Dental anatomy is also a taxonomical science: it is concerned with the naming of teeth and the structures of which they are made, this information serving a practical purpose in dental treatment.

This is a list of definitions of commonly used terms of location and direction in dentistry. This set of terms provides orientation within the oral cavity, much as anatomical terms of location provide orientation throughout the body.

Dental pertains to the teeth, including dentistry. Topics related to the dentistry, the human mouth and teeth include:

Inferior alveolar nerve block is a nerve block technique which induces anesthesia (numbness) in the areas of the mouth and face innervated by one of the inferior alveolar nerves which are paired on the left and right side. These areas are the skin and mucous membranes of the lower lip, the skin of the chin, the lower teeth and the labial gingiva of the anterior teeth, all unilaterally to the midline of the side on which the block is administered. However, depending on technique, the long buccal nerve may not be anesthetized by an IANB and therefore an area of buccal gingiva adjacent to the lower posterior teeth will retain normal sensation unless that nerve is anesthetized separately, via a (long) buccal nerve block. The inferior alveolar nerve is a branch of the mandibular nerve, the third division of the trigeminal nerve. This procedure attempts to anaesthetise the inferior alveolar nerve prior to it entering the mandibular foramen on the medial surface of the mandibular ramus.

<span class="mw-page-title-main">Mandible</span> Lower jaw bone

In anatomy, the mandible, lower jaw or jawbone is the bottom skeleton that makes up the lower half of the mouth in jawed vertebrates. In arthropods, the largest pair of appendages of their mouthparts are also named mandibles.

The face and neck development of the human embryo refers to the development of the structures from the third to eighth week that give rise to the future head and neck. They consist of three layers, the ectoderm, mesoderm and endoderm, which form the mesenchyme, neural crest and neural placodes. The paraxial mesoderm forms structures named somites and somitomeres that contribute to the development of the floor of the brain and voluntary muscles of the craniofacial region. The lateral plate mesoderm consists of the laryngeal cartilages. The three tissue layers give rise to the pharyngeal apparatus, formed by six pairs of pharyngeal arches, a set of pharyngeal pouches and pharyngeal grooves, which are the most typical feature in development of the head and neck. The formation of each region of the face and neck is due to the migration of the neural crest cells which come from the ectoderm. These cells determine the future structure to develop in each pharyngeal arch. Eventually, they also form the neurectoderm, which forms the forebrain, midbrain and hindbrain, cartilage, bone, dentin, tendon, dermis, pia mater and arachnoid mater, sensory neurons, and glandular stroma.

References

  1. ↑ Maton, Anthea; Jean Hopkins; Charles William McLaughlin; Susan Johnson; Maryanna Quon Warner; David LaHart; Jill D. Wright (1993). Human Biology and Health . Englewood Cliffs, New Jersey, USA: Prentice Hall. ISBN   0-13-981176-1.
  2. ↑ Pocock, Gillian (2006). Human Physiology (Third ed.). Oxford University Press. p. 382. ISBN   978-0-19-856878-0.
  3. ↑ Cassidy, Suzanne B.; Dykens, Elisabeth; Williams, Charles A. (2000). "Prader-Willi and Angelman syndromes: Sister imprinted disorders". American Journal of Medical Genetics. 97 (2): 136–46. doi:10.1002/1096-8628(200022)97:2<136::AID-AJMG5>3.0.CO;2-V. PMID   11180221.
  4. ↑ Susan Standring, ed. (2008). Gray's anatomy : the anatomical basis of clinical practice (40th ed.). [Edinburgh]: Churchill Livingstone/Elsevier. ISBN   978-0443066849.
  5. ↑ Lindhe, Jan; Lang, Niklaus P; Karring, Thorkild, eds. (2008) [2003]. Clinical Periodontology and Implant Dentistry 5th edition . Oxford, UK: Blackwell Munksgaard. p. 48. ISBN   9781405160995.
  6. ↑ Lindhe, Jan; Lang, Niklaus P; Karring, Thorkild, eds. (2008) [2003]. Clinical Periodontology and Implant Dentistry 5th edition . Oxford, UK: Blackwell Munksgaard. ISBN   9781405160995.
  7. ↑ Turowski, Jason (2016-04-29). "Should I Breathe Through My Mouth or Through My Nose?". Cleveland Clinic. Archived from the original on Jun 30, 2020. Retrieved 2020-06-28.
  8. ↑ "Squeezable Paint Brushes (Howard University)". RESNA. Rehabilitation Engineering and Assistive Technology Society of North America. 31 May 2014. Archived from the original on 1 March 2016. Retrieved 18 January 2020.
  9. ↑ Winchester, Levi (10 July 2014). "Watch: Woman born without fully-formed limbs creates stunning artwork using her mouth". www.express.co.uk. Daily Express.
  10. ↑ Nascimento, Weslania Viviane; Cassiani, Rachel Aguiar; Dantas, Roberto Oliveira (September 2012). "Gender effect on oral volume capacity". Dysphagia. 27 (3): 384–389. doi:10.1007/s00455-011-9379-4. ISSN   1432-0460. PMID   22120835. S2CID   22688382.
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