| XXX | (295) | XXX |
^ Part VI. ANA T a m Yt. parts of the externa! ’ear, befidts the caiti■ The nofe is the organ of fmelling, -by means of the lage,Theareother ligaments, mufcles, integuments, febaceous and -villous portion of the internal membrane, to which the •olfadory nerves are chiefly difiributed. It is likewife .ceruminous glands, arteries, Veins and'nerves. The cartilage of the outward ear is nearly of the fame •of ufe in refpiratiou; and the mucilaginous fluid fpread extent and figure with the large foiid .portion thereof, alover the whole pituitary membrane, prevents the air mentioned; but it is not of the fame thicknefs, from drying that membrane, arid fo rendering it inca- ready being covered by integuments on both fidcs. Va the pable of being affefted. The nofe ferves likewife to re- lobe or foft low'er portion of the ear, this cartilage is-gulate and modify the voice, and to this the-finufes like- wanting. wife contribute. The facculus lachrymalis receives the The external ear is fixed to the cranium, not only by ferum from the eyes, and difcharges it upon the palate, the cartilaginous portion of the' meatus auditorius, but from whence the greateft part of it runs to the pharynx. alfo by ligaments, which are two ih number, one anterior, the other pefterior. The anterior ligament is fixed by Sect. VII. The Ear. one extremity to the root of the apophyfis zygomatlca of the es temporis, at the anterior and a little toward Anatomists commonly divide or diftinguifli the ear the fuperior part of the meatus clTeiis, clofe to the corinto external and internal. Ey the external ear they ner of the glenoid cavity; and by the other extremity, mean all that lies without the external ori Ice of the me- to the anterior and faperior pan of the cattilaginous meatus auditorius in the os temporis; and by the internal The pofiericr ligament is fixed by one end to the ear, all that lies within the cavities of that bone, and alroot of the maftoid apophyfis, and by the other to the ■to the parts that bear any relation thereto. The greateft part of the external ear confifts of a large pofte'rior part of the convexity of the concha,, fo that it cartilage very artificially framed, which is the bafis of is oppofite to the anterior ligament. , all the other parts of which this' portion of the ear is Of the mufcles of the external ear, fame go between made up. The internal ear confifts chiefly of feveral the cartilages and the os temporis, others are confined to bony pieces, partly formed in the fubftance of the ofia the cat tilages alone. Both kinds vary in different fubtemporum, and efpecially in that portion of it calledrf- jefts, and are foiuetimes fo very thin, as to Icok more ■pophyjispetrofa, and partly feparated from, but contain- like ligaments than mufcles. The mufcles of the firft ed in a particular cavity of that bone. kind are generally three in number, one fuperior, cr.e The external ear, taken altogether, refembles in fome pofterior, and ere anterior. T he fuperior mufcle is fixdegree the /hell of a mufiel, with its broad end turned ed in the convexity ef the foffii navicularis, and of the upward, the fmall end downward, the convex fide next fnperior portion of the concha; from whence it tuns up the head, and the concave fide outward Two portions to the fejuamoas portion of the ps temporis, expanding are diftingui/hed in the external ear taken all together; in a. radiated manner, and is inferred principally in the one large and foiid, called in Latin pinna, which is the Jigamentary apOneUrofis, which covers the poftetior poifuperior, and by much the greateft part; the ether tion of the temporal rnufele. imall and foft, called the/^e, which makes the lower The anterior tunfcle is fmall, more or lefis inverted, part. like an appendix to the fuperior. Ir is fixed by one The forefide is divided'into eminences and cavities. and extremity above the root of the zygomatic apophyfis, and The eminences are four in number, called helix, ant he- by the other in the americr part of the convexity of the lix, tragus, and antitragus. The helix is the large concha. folded border or circumference of the great portion of The. pofterior mufcle is almoft tranfverfe, and of -a the ear. The amhtlix is the large oblong eminence or confiderable bVeadth, being fixed by one end to the perifing furrounded by the helix. The tragus is the fmall fterior part of the convexity of the concha,, and by the anterior protuberance below the anterior extremity of other in the root of the ftiafloid apophyfis. the helix, which in an advanced age is covered with hairs. The fmall mufcles which are confined to the cartilages The antitragus is the pofterior tubercle below ike infe- are only fmall ftrata of fibres found on both fitles of tire rior extremity of the anthelix. cartilages. The cavities on rite forefide are four in number; the The lobe of the ear, or that foft portion which lies hollow of the helix ; thedepmfiion at the fuperior extre- Under agtitriigus, and meatus auditorius, is mity of the anthelix, called fo[fa navicular is; the con- made uptheof tragus, nothing but ikin and cellular fubftauce. The cha, or great double cavity that lies under the rifing term- meatus auditorius is bony, and partly Cartilaginous. ed antbdix, the upper bottom of which, is diftinguiftied The bony portion ispartly the longtft, and fai ms the bottom from the lower by a continuation of the helix in form ef die canal. The cartilaginous portion is the ftterteft, of a tranfverfe crifta ; and laftly, the meatus of the ex- and forms the external opening or orifice of the canal. ternal ear fiiuated at the lower part of the bottom of the Tbefe two portions joined tndwife to each other, form concha. a canal of about three quarters of an inch in length, t f The backfide of the external ear ftiew's only one con- different widenefs in its different parts, and a little cc nfiderable eminence, which is a portion of the convex fide torted. lined on the infide by the fliin and •cellular of the concha, the other portion being hid by the adhe- membrane,It isthrough its whole length; and thus thefie infion. of the ear to the os tempens. teguments make up for the breaks in the cartilaginous yorricB*.
