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 Part V. 250 A N A T O M Y. nerves to the tongue, larynx, pharynx, and ganglion of al nerves from them, it forms a large ganglion, into the intercoftal nerve, and being disjoined from the ninth which branches from the tenth of the head, and from the and intercoftal, to which it adheres clofely fome way, firft and fecond cervical, enter. From this ganglion the runs (height down the neck behind the internal jugular nerves come out again fmall, to run down the neck along vein, and at the external fide of the carotid artery. As with the carotid artery, communicating by branches with it is about to enter the thorax, a large nerve goes off from the cervical nerves, and giving nerves to the mufcles that the eight of each fide: This branch of the right-fide bend the head and neck. As the intercoftal is about to turns round from the fore to the back part of the fubcla- enter the thorax, it forms another ganglion, from which vian artery, while the branch of the left-fide turns round nerves are fent to the trachea and to the heart; thefe the great curve of the aorta ; and both of them mounting defigned for the heart joining with the branches of the up again at thel de of the oefophagus, to which they eighth, and moft of them pafling between the two great give branches, are loft at laft in the larynx. Thefe are arteries and the auricles, to the fubftance of that mufcle. called the Recur rent nerves, which we are defired to The interco'ftal after this confifting of two branches, one fliun in the operation of bronchotomy, though their deep going behind, and the other running over the fore-part of the fubclavian artery, forms a new ganglion where the iituation protects them fufficiently. The eighths pair, above, and at or near the place where two branches unite below that artery, and then defendthe recurrent nerves go off from it, or frequently the ing along the fides of the vertebrae of the thorax, rerecurrents themfelves, fend off fmall nerves to the peri- ceives branches from each of the dorfal nerves; which cardium, and to join with the branches of the intercoftal branches appearing to come out between the ribs, have that are diftributed to the heart; but their fize and fi- given the name of intercoftal to the whole nerve. Where the addition is made to it from the fifth dorfal nerve, a tuation are uncertain. After thefe branches are fent off, the par vagum on branch goes off obliquely forewards ; which being joined each fide defcends behind the great branch of the trachea, by fuch branches from the fixth, feventh, eighth, and and gives numerous filaments to the lungs, and fome to ninth dorfal, an anterior trunk is formed, and paffes bethe heart in going to the cefophagus. The one of the tween the fibres of the appendix mufculofa of the dialeft-fide running on the fore-part of the oefophagus, com- phragm, to form, along with the other intercoftal and municates by feveral branches with the right one in its the branches of the eighth pair, a large femilunar gandefcent to be diftributed to the ftomach : The right one glion fituated between the cseliac and fuperior mefenteric gets behind the oefophagus, where it fplits and rejoins fe- arteries ; the roots of which are as it were involved in a veral times before it arrives at the ftomach, to which it fort of nervous net-work of this ganglion, from which a fends nerves; and then being joined by one or more great number of very fmall nervous threads run out to branches from the left trunk, they run towards the cseliac be extended on the furface of all the branches of thofe artery, there to join into the great femilunar ganglion two arteries, fo as to be eafily feen when any of the arteries are ftreiched, but not to be raifed from formed by the two intercoftals. The Ninth Pair of nerves comes from the inferior them by diffedtion; and thus the liver, gall-bladder, part of the corpora pyramidalia, to go out of the fkull duodenum, pancreas, fpieen, jejunum, ilium, and a large at their proper holes of the occipital bone. After their (hare of the colon, have their nerves fent from this great egrefs they adhere for fome way firmly to the eighth and folar ganglion or plexus. intercoftal; and then fending a branch, that in many Several fibres of this ganglion, running down upon fubjedts is joined with branches of the firft and fecond the aorta, meet with other nerves fent from the pofterior cervical nerves, to be diftributed to the thyroid gland and trunk of the intercoftal, which continues its courfe along mufcles on the fore-part of the trachea arteria, the ninth the fides of the vertebra, they fupply the glandulss renales, kidneys, and teftes in men, or ovaria in women; is loft in the mufcles and fubftance of the tongue. The Tenth Pair rifes in feparate threads from the and then they form a net-work upon the inferipr mefenfides of the fpinal marrow, to go out between the os oc- teric artery where the nerves of the two fides meet, cipitis and firft vertebra of the neck. After each of and accompany the branches of this artery to the part them has given branches to the great ganglion of the in- of the colon that lies in the left fide of the belly, and to tercoftal, 8th, 9th, and ift cervical nerves, it is diftri- the return, as far down as to the lower part of the pelvis. buted to the (freight, oblique, and fome of the extenfor The intercoftal continuing down by the fide of the vermufcles of the head. tebra of the loins, is joined by nerves coming from beThe branch reflected from the fixth pair, joined pofli- tween thefe vertebra, and fends nerves to the organs of bly by fome filaments of the opththalmic branch of the generation and others in the pelvis, being even joined fifth, runs along with the internal carotid artery, through with thofe that are fent to the inferior extremities. the crooked canal formed for it in the temporal bone, where The Spinal Nerves rife generally by a number of the little nerve is very foft and pappy, and in feveral difgregated fibres from both the Fore and back part of the fubjedts divides and unites again, and is joined by one or medulla fpinalis, and foon after form a little knot or ganmore branches from the fifth particularly of its fuperior glion, where they acquire ftrong coats, and are extendmaxillary branch, before it comes out of the fkull. As ed into firm cords. They are diftinguifhed by numbers, foon as the nerve efcapes out of this bony canal, it is according to the vertebra from between which they connedted a little way with the eighth and ninth; then come out; the fuperior of the two bones forming the hole feparating from thefe, after feeming to receive addition- through which they pafs, being the one from which the number