PHARYNX and Mount. (Gr. eparyt.)— The pharynx is a large, muscular, and membra nous pouch, placed behind the nose, mouth, and larynx, and resting upon the cervical vertebrte : it extends from the base of the skull above to a level with the fourth or fifth cervical vertebra and the lower border of the cricoid cartilage, and is at this point continued into the (esopha gus : it occupies the middle line of the body and is a symmetrical organ : of a very irregu larly funnel-shaped form, it is wide above and open in front to the cavities of the nose and mouth, and contracts as it descends behind the larynx : by the relation of this latter organ the interior of the pharynx is converted into a tube to be continued downwards to the stomach under the name of cesophagus. A common channel to the digestive and respiratory pas sages, it is alike beautifully adapted by its con struction, on the one hand to receive the food and convey it onward to the alimentary canal, and on the other to preserve a perfectly free communication between the atmospheric air and organs of respiration : to this latter function may be added the power of modulating vocal sounds.
As the pharynx is so closely associated, both in function and anatomical relation, with the mouth and palate, I shall subjoin to its de scription that of these latter organs. In the further examination of the pharynx the fol lowing arrangement will be adopted. lst. The description of its aponetirosis and muscles. 2ndly. Its attachments considered generally. 3rdly. To examine its cavity with the several openings related to it. 4thly. The mucous membrane and glandular apparatus ; and, lastly, the vessels and nerves distributed to it.
1. The fibrous menzbrane.—Thisaponeurosis, named cephalo-pharyngeal, contributes to the formation of the pharyngeal parietes above, and is essentially the means by which the pha rynx is affixed to the base of the skull : it forms a sort of framework for the support of the mus cular and mucous tunics above, and is imper ceptibly lost as it descends between these structures : it is thin but strong and well marked superiorly, and connected, by uniting intimately with the periosteum, to the under surface of the basilar process of the occipital bone, and, by a particularly dense slip, to its spine centrally ; this latter may be considered as the origin of that tendinous raphe which, descending in the median line along the back of the pharynx, acts as an uniting medium to the constrictor muscles of either side : the basilar attachment of the cephalo-pharyngeal aponeurosis occurs immediately anterior to the insertions of the recti capitis antici muscles, and is consequently some little distance in ad vance of the occipital condyles and foramen : extending laterally, the aponeurosis next springs from the under surface of the petrous portion of the temporal bone as far outwardly as the external orifice of the carotid canal, just an terior and internal to which it turns suddenly forwards and inwards, forming a sharp angle, then passes beneath the inner surface of the levator palati muscle, to attach itself to the car tilaginous portion of the Eustachian tube, near the anterior extremity of which it terminates by being gradually lost upon the mucous mem brane: descending from these several points, and bounding the upper part of the pharyngeal cavity posteriorly and laterally, it insinuates itself between the mucous membrane and su perior constrictor muscle, and splitting up into filaments which pass between the numerous mucous glands that are found at this part of the pharynx is lost from an inch to two inches below the base of the skull posteriorly, on either side the median line, and between the upper semicircular margins of the superior constrictor muscles and the base of the skull, a considerable part of this appneurosis.is unco
vered by muscular fibres, constituting what are called the sinuses of Morgagni: the fibrous membrane is of great width at its origin, the external carotid fommina marking off the la teral limits, but it quickly narrows as it de scends : the sharp angle which it forms is brought into relation with the internal carotid artery and superior cervical ganglia of the sym pathetic nerve: in the interior of the pharynx a longitudinal sulcus, sometimes crossed by a transverse slip, will be found behind the open ing of the Eustachan tube, leading to a cul-de sac which occupies this angle.