mouth

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The oral or buccal cavity and its related structures. The oral cavity forms in the embryo from an in-pocketing of the skin, the stomodeum; it is thus lined by ectoderm and is not, properly speaking, part of the digestive tract. Functionally, however, the mouth forms the first portion of both the digestive and respiratory systems. Various special structures are found in, or associated with, the mouths of most vertebrates. See also Digestive system; Respiratory system.

Teeth may be present to help grasp or grind food. In most vertebrates they are relatively simple cones but in some, especially mammals, they are of diverse shapes. See also Dentition; Tooth.

Various glands are associated with the mouth. These are of infrequent occurrence in fish but are found in most tetrapods. Humans have three pairs of salivary glands: the parotid, submaxillary, and sublingual. In forms such as some snakes salivary glands may produce a poison used to subdue prey.

Other structures also vary greatly. Most tetrapods have a mobile tongue attached to the floor of the mouth, but few fish do. The structure of the roof of the mouth, or palate, is quite different in different groups. See also Palate; Tongue.

In mammals, including humans, the margins of the lips mark the junction between the outer skin and the inner mucous lining of the oral cavity. The mucosa of the mouth forms the lining and the gums surrounding the teeth and covers the surface of the tongue. The roof of the mammalian mouth consists of the hard palate and, behind this, the soft palate which merges into the oropharynx. The lateral walls consist of the distensible cheeks, and the floor is formed principally by the tongue and the soft tissues that lie between the two sides of the lower jaw, or mandible.

The posterior limit of the oral cavity of mammals is marked by the fauces, an aperture which leads to the pharynx. On either side of the fauces are two muscular arches covered by mucosa, the glossopalatine and pharyngopalatine arches; between them lie masses of lymphoid tissue, the tonsils. Suspended from the posterior portion of the soft palate is the soft retractable uvula. See also Tonsil.

The poetic (and biblical) view of the mouth and lips is almost entirely romantic and idealized — ‘… the lips of a strange woman drop as a honeycomb, and her mouth is smoother than oil …’ (Proverbs), although an occasional writer illustrates the downside — ‘I've a head like a concertina, I've a tongue like a button stick, I've a mouth like an old potato, and I'm more than a little sick …’ (Kipling).

It is a rather unromantic fact, however, that the mouth is functionally the first part of the gastrointestinal tract — one end of the nutritional tube which starts there and ends at the anus. Because of its position it has acquired many other complementary functions — as a part of the respiratory system, for instance and as a most important part of the speech mechanism — but these are secondary to its main function. In the human embryo the first sign of the potential mouth (or oral cavity) occurs in the fourth week of development and is a small depression in what will become the skin of the face. The depression deepens and quite rapidly meets up with the developing upper part of the gastrointestinal tube. The separating tissues disappear, and the embryo mouth is left in continuity with the rest of the gastrointestinal tract. The oral mucous membrane includes many specialized features; the salivary glands, large and small, are derived from it, and it contains numerous sensory endings of various types. These include those in the taste-buds, the structures which are responsible (together with those in the nose mediating the sense of smell) for the recognition of flavour. Other types of nerve endings in the oral mucosa include those concerned with the sense of touch, recognition of temperature changes, and so on. In appropriate situations these provide signals to other parts of the body, stimulating the secretion of saliva, inducing gastric activity, initiating sexual awareness, and carrying out many other functions.

The bony structures within which the soft tissues of the mouth are contained are essentially the jaws (the mandible and the maxilla, including the palate) which, together with the precursors of the teeth, are formed as a later part of the developmental process described above. The system of embryonic structures involved in the formation of the mouth, lips, and jaws is complex, and the possibility of developmental errors occurring during this process is well known. In this highly visible and emotionally significant area of the body, failure of the normal processes, with resulting cleft formation, may be a highly traumatic matter for the individual involved. The integrity of the oral cavity and its relative proportions to the nearby structures, such as the nasal space and the sinuses, also largely determine the nature of speech, as the oral cavity is one of the series of resonators distributed about the base of the skull, which are greatly involved in modifying the primary speech (and song) sounds produced in the larynx.

In almost all of the functions of the mouth, the tongue and the teeth are closely involved. Perhaps less evident is the role of the saliva in this respect. As a lubricant with autonomic nervous system control of its flow (who has not had a dry mouth when subjected to almost any form of stress?), an adequate salivary flow is an absolutely vital factor for the success of most of the functions performed within the oral cavity.

The superficial margin of the mouth is marked by the lips — essentially the functional sphincter structure which seals off the mouth from the external environment, but with the ability to perform complex and sophisticated movements which quite transcend this simple function. The ring of individually controlled muscles in the substance of the lips, together with others in the facial structure, some of which are concerned predominantly with opening and closing the jaws, make up a highly complex system of control for the mouth, the lips, and the face in general. These include the group of the ‘muscles of expression’, which work with an integrated nerve supply to provide this vitally important mechanism of communication and of expression of emotion.

The mouth is, quite clearly, a primary erogenous zone. In itself it is not a particularly attractive structure, but the lips are a different matter. The smile is on the lips of the Mona Lisa — at least in the popular view, although quite clearly the facial expression as a whole is involved in such aesthetic assessments. ‘Thin lipped’, ‘thick lipped’ and similar characterizations depend on the description of only one feature of a face, but evidently a crucial one.

When things go wrong in the mouth the emotive effect may be disproportionally high. The mouth and lips are of great importance aesthetically, sexually, and functionally. Perhaps because of this, the area is also the site of many well-recognized psychogenic disorders involving unexplained pain and unusual sensations. Because of the duplex origin of the oral mucous membrane, diseases both of the skin and of the gastrointestinal tract, as well as those of more localized origin, may manifest in the mouth. Many of these cause pain, and the impact on the individual may be very significant — speech, eating, and the other functions in which the mouth is involved may all be affected, and the overall effect may be disproportionately great. Even minor conditions affecting the lips may be particularly troublesome — the simple cold sore causes distress, not only because of the irritation, but also because of its very visible site.

— William Tyldesley

See also autonomic nervous system; cleft lip and palate; face; saliva; taste and smell; teeth; tongue.

noun

1. The opening in the body through which food is ingested: Slang gob², puss, trap. See mouth.
2. A facial contortion indicating displeasure, disgust, or pain: face, grimace, moue, pout. Informal mug. See express.
3. A person who speaks on behalf of another or others: speaker, spokesman, spokesperson, spokeswoman. Informal mouthpiece. See substitute.
4. An open space allowing passage: aperture, hole, opening, orifice, outlet, vent. See open/close.

verb

1. To speak in a loud, pompous, or prolonged manner: declaim, harangue, perorate, rant, rave. See words.
2. To contort one's face to indicate displeasure, disgust, or pain, for example: grimace, mug. Idioms: make a face, make faces. See express.

In addition to the idiom beginning with mouth, also see bad mouth; big mouth; butter wouldn't melt in one's mouth; down in the dumps (mouth); foam at the mouth; foot in one's mouth; from the horse's mouth; hand to mouth; have one's heart in one's mouth; keep one's mouth shut; laugh out of the other side of one's mouth; leave a bad taste in one's mouth; look a gift horse in the mouth; make one's mouth water; melt in one's mouth; not open one's mouth; out of the mouths of babes; put one's money where one's mouth is; put words in someone's mouth; run off at the mouth; shoot off one's mouth; take the bit in one's mouth; take the bread out of someone's mouth; take the words out of someone's mouth; word of mouth.

On the analogy that an itch on particular parts of the body is significant of some future event, two early writers refer to an itching mouth or lips:

My mouth has itched all this long day
That is a sign of kissing at least
(Chaucer, ‘Miller's Tale’ (c.1387), lines 3683-4)

n.

In man, the gateway to the soul; in woman, the outlet of the heart.

A big mouth indicates gossip and the spreading of lies, or perhaps spoken words of goodness and truth. Romantic or sexual urges are associated with this symbol too.

An opening, especially the oral cavity, which forms the beginning of the digestive system and in which the chewing of food takes place. It is also the site of the organs of taste and the teeth, tongue and lips, and the entrance to the body for food and sometimes air. In animals it is a part of the system of defense and attack. Called also oral cavity, buccal cavity. See also oral.

• African m. breeders — fish that breed in isolated pairs and the spawn of which are incubated in the mouth of the male. Called also Tilapia macrocephala.
• m. carcinoma — in food animals may occur in those eating bracken. It is usually a squamous cell carcinoma of gum epithelium.
• m. dryness — characteristic of dehydration, atropine poisoning.
• m. erosions — erosive stomatitis.
• full m. — a mature animal with all teeth erupted and in wear.
• m. gag — see mouth speculum (below).
• m. inflammation — see stomatitis, gingivitis, glossitis, etc.
• monkey m. — mandibular prognathism; undershot jaw.
• m. mucosal lesions — includes stomatitis, necrobacillosis, ulcer, foreign body lodgment, laceration.
• m. necrobacillosis — necrosis, ulceration caused usually by Fusobacterium necrophorum.
• m. neoplasms — see oral neoplasm.
• parrot m. — see brachygnathia.
• paw and m. disease — a name for feline calicivirus or herpesvirus infection because of the infrequent occurrence of ulcerations on the skin, usually of the front paws, as well as the usual location in the mouth; probably the result of transmission from grooming.
• scabby m. — see contagious ecthyma.
• shear m. — malocclusion producing marked pointing of the enamel. Seen particularly in horses.
• m. shyness — avoidance of handling around the mouth may be a sign of dental disease in animals.
• sow m. — mandibular prognathism; undershot jaw.
• m. speculum — a device for preventing the mouth from being closed which permits the passage of the hand or an easily damaged piece of equipment such as a rubber stomach tube. See also frick, mcpherson, schoupe, drinkwater, bayer specula. There are several unnamed pieces: a wooden one used in cows, which is inserted crossways between the teeth and a stomach tube passed through a hole in its middle; a metal one used in horses by placing its two dental plates over the tables of the incisor teeth and screwing them apart with a thumbscrew working inside the frame that supports the plates; and a similar, simpler device used in sheep and small pigs which has two horizontal bars running crossways between the two parallel prongs of a handheld, fork-like device. It is inserted horizontally between the molar teeth and then turned to a vertical position.
• m. ulcers — in large animals, ulcers of the oral mucosa usually caused by secondary bacterial infection of less severe mucosal lesions caused by a primary disease, e.g. mucosal disease. In cats, ulcerations are often associated with feline viral respiratory disease complex.
• m. wart — a common location for infection by papilloma virus.
• wry m. — a twisted mouth caused by unilateral malocclusion.

The oral cavity.

• Head and Neck - mouth: opening framed by lips through which food enters body; speech organ
• Mouth and Teeth - mouth: opening through which food enters body, also used in forming speech sounds
• Inland Waterways and Lakes - mouth: point where stream enters lake or sea
• Intonation and Inflection - mouth: form words with lips only; declaim with exaggerated distinction

Dansk (Danish)
n. - mund, mundhule, åbning, indgang, munding
v. tr. - deklamere overdrevent, sige affekteret, berøre med munden, smage på (om mad), sladre
v. intr. - deklamere overdrevent, bevæge læberne stille, lave grimasser

idioms:

• keep one's mouth shut    holde tæt
• mouth organ    mundharmonika
• open one's mouth    åbne munden

Nederlands (Dutch)
mond, ingang, muil, bek, monding, oreren, bekkentrekken, de lippen bewegen, murmeren, declameren, uitmonden, bijten in, zorgvuldig kauwen, aan bit laten wennen

Français (French)
n. - bouche, gueule, museau, entrée (d'un tunnel, d'une cave), embouchure (d'une rivière), bouche (d'un volcan), débouché (d'une vallée), goulot (d'une bouteille), ouverture (d'un sac), (fig) bavardage, (surveiller son) langage
v. tr. - articuler silencieusement, débiter (des platitudes) (péj), mettre (qch) dans sa bouche
v. intr. - mimer, (US) déclamer

idioms:

• keep one's mouth shut    se taire
• mouth off    tempêter (à propos de, contre qn), (US) répondre insolemment, (US) dégoiser, déballer (des opinions)
• mouth organ    harmonica
• open one's mouth    ouvrir la bouche

Deutsch (German)
n. - Mund, Maul, Mündung, Öffnung, Einfahrt
v. - (Wörter) mit den Lippen formen, daherreden, Grimassen schneiden

idioms:

• keep one's mouth shut    den Mund halten
• mouth off    (ugs) schreien, prahlen
• mouth organ    Mundharmonika
• open one's mouth    seinen Mund aufmachen

Ελληνική (Greek)
n. - στόμα, στόμιο, μπούκα, (γεωγρ.) εκβολή ποταμού
v. - φθέγγομαι, μιλώ ή λέγω με στόμφο, καταπίνω, χάφτω

idioms:

• hand to mouth    μεροδούλι-μεροφάι
• keep one's mouth shut    κρατάω το στόμα μου κλειστό
• mouth organ    (μουσ.) φυσαρμόνικα
• open one's mouth    ανοίγω το στόμα μου, μιλώ

Italiano (Italian)
bocca, fauci, foce

idioms:

• keep one's mouth shut    tenere la bocca chiusa
• mouth organ    armonica
• open one's mouth    aprire la bocca

Português (Portuguese)
n. - boca (f), trejeito (m), desembocadura (f)
v. - caretear, levar à boca, falar com afetação

idioms:

• keep one's mouth shut    manter a boca fechada
• mouth organ    gaita (f) (Mús.)
• open one's mouth    queixar-se

Русский (Russian)
рот, едок, гримаса, высокопарно говорить, хватать губами, гримасничать

idioms:

• keep one's mouth shut    держать язык за зубами
• mouth organ    губная гармоника, свирель
• open one's mouth    открыть рот

Español (Spanish)
n. - boca, hocico, desembocadura
v. tr. - decir, proferir, vocear, hacer muecas, falsear, ponerse algo en la boca, hacerle la boca al caballo
v. intr. - hablar, gritar, declamar, desembocar, hacer muecas

idioms:

• keep one's mouth shut    no decir esta boca es mía
• mouth off    expresar las opiniones propias, replicar
• mouth organ    armónica
• open one's mouth    abrir la boca, revelar algo

Svenska (Swedish)
n. - mun, grimas, mynning
v. - deklamera, forma med läpparna, beröra med munnen, sluka, skvallra, mynna

中文（简体）(Chinese (Simplified))
嘴, 口, 需抚养的家属, 言辞, 不出声地说, 言不由衷地重复, 装腔作势地说, 装腔作势地说话, 夸大地说话

idioms:

• keep one's mouth shut    保持缄默, 守口如瓶
• mouth organ    口琴
• open one's mouth    开口说话, 张口

中文（繁體）(Chinese (Traditional))
n. - 嘴, 口, 需撫養的家屬, 言辭
v. tr. - 不出聲地說, 言不由衷地重復, 裝腔作勢地說
v. intr. - 裝腔作勢地說話, 誇大地說話

idioms:

• keep one's mouth shut    保持緘默, 守口如瓶
• mouth organ    口琴
• open one's mouth    開口說話, 張口

한국어 (Korean)
n. - 입, 병 주둥이
v. tr. - (소리내지 않고) 속삭이다, 물다, (과장하여) 말하다
v. intr. - 큰 소리로 말하다, (지류가) 흘러 들다

idioms:

• keep one's mouth shut    (비밀을) 지키다

日本語 (Japanese)
n. - 口, 開口部, 出入り口, ことば, 発言, 養うべき人, 人, 動物, 噂, 口答え
v. - 気取って言う, 口に入れる, くわえる, なめる

idioms:

• from the horse's mouth    一番確かな筋から
• mouth organ    ハーモニカ
• put words into someone's mouth    気持ちだと勝手に人に言う, 言いもしない事を言った事にする

العربيه (Arabic)
‏(الاسم) فم, كشرة, ناطق بلسان, تعبير (فعل) يتكلم‏

עברית (Hebrew)
n. - ‮פה, פתח, כניסה, יציאה, פטפטנות, זמם (מחסום לבהמה)‬
v. tr. - ‮הביע בחגיגיות, מלמל, הכניס לפה, נגע בפה, הביע בבירור, דקלם, הכניס מתג (לפי הסוס)‬
v. intr. - ‮דיבר בחגיגיות, הניע שפתיים בלי לדבר, עשה העוויה‬