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PHARYNGITIS
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PHARYNGITIS . The pharynx, or upper portion of the gullet (seen to a large extent on looking at the back of the mouth) is frequently the seat of a chronic inflammatory See also:condition, usually associated with derangements of the See also:digestive See also:organs, or with syphilis or See also:gout; sometimes it is due to much speaking or to excessive See also:tobacco-smoking—especially of cigarettes. On inspection, the inflamed mucous membrane is seen unduly red and glazed, and dotted over with enlarged follicles. The condition produces considerable irritation and " dryness," with cough and discomfort, which may eventually become chronic. Treatment consists in removing all See also:sources of irritation, in rectifying gastric disturbance, and in the application of the electric cautery, of astringent lotions or of mild See also:caustic solutions. The See also:pain may be relieved by spraying with certain See also:anodyne solutions. In the See also:case of adenoid growths (see See also:ADENOIDS) there is often an associated granular See also:appearance of the pharynx, due to enlargement of the See also:minute glands of the mucous membrane. The inflamed pharynx of the orator (" clergyman's sore-See also:throat ") may be put right by lessons in elocution or by See also:complete See also:rest for a See also:time. The gouty throat may See also:call for a See also:change of See also:diet, or for a stay at one of the watering-places where See also:early rising, moderatefood, See also:regular exercise and the drinking of laxative See also:waters join in restoring See also:health. (E. O.*) PHARYNX (Gr. 4apvyE, throat), in See also:anatomy, the cavity into which both the See also:nose and mouth See also:lead, which is prolonged into the See also:oesophagus or gullet below, and from which the larynx or See also:air See also:tube comes off below and in front; it therefore serves as a passage both for See also:food and air. It may be likened to an empty See also:sack turned upside down and narrowing toward its mouth. The back and sides of the sack are formed by the three constrictor muscles of the pharynx, each of which overlaps the See also:outer See also:surface of the one above it, and these are lined internally by thick mucous membrane. The upturned bottom of the sack is attached firmly to the See also:base of the See also:skull and the See also:internal pterygoid plates, so that this See also:part cannot collapse, but below the anterior and posterior walls are in contact, and a transverse See also:section of the pharynx is a See also:mere slit. From the front See also:wall, on a level with the See also:floor of the nose and See also:root of the mouth, a slanting shelf of See also:muscular and glandular See also:tissue covered with mucous membrane, projects downward and backward into the cavity, and divides it into an upper part or naso-pharynx and a See also:lower or oral pharynx (see fig.). This shelf is the soft See also:palate, a.nd from the See also:middle of its See also:free border hangs a See also:worm-like See also:projection, of variable length but averaging about See also:half an See also:inch, the uvula. The whole of the front wall of the naso-pharynx is wanting, and here the cavity opens into the nose through the posterior nasal apertures (see OLFACTORY See also:SYSTEM). On each See also:side of the nasopharynx, and therefore above the soft palate, is the large triangular opening of the Eustachian tube through which air passes to the tympanum (see See also:EAR). Behind this opening, and reaching up to the roof of the naso-pharynx, is a See also:mass of lymphoid tissue, most marked in See also:children, known as the pharyngeal tonsil. This tissue, when it hypertrophies, causes the disease known as " adenoids." From the See also:mid-See also:line of the roof of the pharynx a small pouch, the bursa pharyngea, best seen in childhood, projects upward, while on each side, above and behind the opening of the Eustachian tube, is a depression known as the lateral See also:recess of the pharynx. The oral pharynx communicates with the naso-pharynx by the pharyngeal See also:isthmus behind the free edge of the soft palate. Above and in front it is continuous with the cavity of the mouth, and the demarcation between the two is a See also:ridge of mucous membrane on each side See also:running from the soft palate to the side of the See also:tongue, and caused by the projection of the palato-glossus muscle. This is known as the anterior See also:pillar of the See also:fauces or anterior See also:palatine See also:arch. About half an inch behind this ridge is another, made by the palato-pharyngeus muscle, which gradually fades away in the side of the pharynx below. This is the posterior pillar of the fauces or posterior palatine arch, and between it and the anterior is the fossa (tonsilar sinus) in which the tonsil lies. The Tonsil is an See also:oval mass of lymphoid tissue covered by mucous membrane which dips in to See also:form mucous crypts; externally its position nearly corresponds to that of the See also:angle of the See also:jaw. It is very vascular, deriving its See also:blood from five neighbouring See also:arteries. Below the level of the tonsil the anterior wall of the pharynx is formed by the posterior or pharyngeal surface of the tongue (q.v.), while below that is the epiglottis and upper opening of the larynx which is bounded laterally by the aryteno-epiglottic folds (see See also:RESPIRATORY SYSTEM). On the lateral side of each of these folds is a See also:pear-shaped fossa known as the sinus pyriformis. Below this the pharynx narrows rapidly until the level of the lower border of the cricoid See also:cartilage in front and of the See also:sixth cervical vertebra behind is reached ; here it passes into the oesophagus, having reached a See also:total length of about five inches. The mucous membrane of the naso-pharynx, like that of the rest of the respiratory See also:tract, is lined by ciliated columnar epithelium, but in the oral pharynx the epithelium is of the stratified squamous variety. Numerous racemose glands are See also:present (see See also:EPITHELIAL TissuEs), as well as patches of lymphoid tissue especially in See also:child-See also:hood. Outside the mucous membrane and separating it from the constrictor muscles is the pharyngeal See also:aponeurosis, which blends above with the periosteum of the base of the skull. See also:Embryology.—The pharynx is partly formed from the ectodermal stomatodaeal invagination (see EMBRYOLOGY and MOUTH) and partly from the fore gut, which is the cephalic part of the entodermal mesodaeum. Up to the fifteenth See also:day (see MOUTH), the bncco-pharyngeal membrane separates these structures, and, though no vestiges of it remain, it is clear that the upper and front part of the naso-pharynx is stomatodaeal while the rest is mesodaeal. The five visceral See also:arches with their intervening clefts or pouches surround the pharynx, and the Eustachian tube is a remnant of the first of these. The second pouch is represented in the adult by the tonsilar sinus, and until lately the lateral recess of the pharynx was looked upon as part of the same, but it has now been shown to be an See also:independent diverticulum. The sinus pyriformis probably represents that part of the See also:fourth groove from which the lateral lobes of the See also:thyroid See also:body are derived. The Bursa pharyngea was at one time looked upon as the See also:place whence the pituitary body had been derived from the roof of the pharynx, but this is now disproved and its meaning is unknown The tonsil is formed in the second branchial cleft or rather pouch, for the clefts are largely incomplete in See also:man, about the fourth See also:month; its lymphoid tissue, as well as that elsewhere in the pharynx, is formed from lymphocytes in the subjacent mesenchyme (see EMBRYOLOGY), though whether these wander in from the blood or are derived from See also:original mesenchyme cells is still doubtful. The See also:Superior meatus of nose Genioglossus Geniohyoid Lymphoid follicle Hyoid bonethese form the simplest type of true internal gills. In the larval See also:lamprey (Ammocoetes) there are eight gill slits opening from the pharynx, but in the adult (Petromyzon) they are reduced to seven, and a septum grows forward separating the ventral or branchial part of the pharynx from the dorsal or digestive part. Both these tubes, however, communicate near the mouth. In fishes there are usually five pairs of gill slits, though a rudi- mentary one in front of these is often present and is called the spiracle. Occasionally, as in Hexanchus and Heptanchus, there may be six or seven slits, and the See also:evidence of See also:comparative anatomy is that fishes formerly had a larger number of gill slits than at present. In the Teleostomi, which include the bony fishes, there is an See also:external gill See also:cover or operculum. In the Dipnoi or mud See also:fish the See also:work of the gills is shared by that of the lungs, and in the See also:African form, Protopterus, external gills, See also:developed from the ectodermal parts of the gill slits, first appear. In the tailed Amphibians (Urodela) the first and fifth gill clefts are never perforated and are therefore in the same condition as all the gill clefts of the human embryo, while in the gilled salamanders (Necturus and See also:Proteus) only two gill clefts remain patent. The gills in all the See also:Amphibia are external and of ecto- dermal origin, but in the Anura (frogs and toads) these are succeeded before the See also:meta- morphosis from the See also:tadpole See also:stage by internal gills, which, unlike those of fish, are said to be derived from the ectoderm. In the embryos of the See also:Sauropsida (See also:reptiles and birds) five gill clefts are evident, though the posterior two are seldom at any time perforated, while in the See also:Mammalia the rudiments of the fifth cleft are no longer found in the embryo, and in man, at all events, none of them are normally perforated except that part of the first which forms the Eustachian tube. It will thus be seen that in the See also:process of phylogeny there is a See also:gradual suppression of the gill clefts beginning at the more posterior ones. The soft palate is first found in crocodiles as a membranous structure, and it becomes Epiglottis muscular in mammals. The bursa pharyngea and pharyngeal tonsil are found in several of the lower mammals. In the See also:sheep the latter is particularly large. For literature and further details, see R. Wiedersheim's Comparative Anatomy of Vertebrates, translated by W. N. See also:Parker (See also:London, 1907) ; also Parker and Haswell's Cricoid cartilage See also:Zoology (London, 1897). (F. G. Additional information and CommentsThere are no comments yet for this article.
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