NECK. 



575 



the nervus vagus lies deeply between tlie two 

 vessels and behind them ; the cellular mem- 

 brane, which invests and binds them together, 

 appears to form an indistinct septum to isolate 

 the artery ; crossing the front of the sheath, 

 from the median line toward the jugular trunk, 

 opposite which they pierce are many veins, 

 of which some are occasionally considerable in 

 size: they are branches from the larynx, trachea, 

 thyroid body, and sub-hyoid muscles, and 

 among them, when it exists, must be counted 

 the anterior jugular : they are capable of caus- 

 ing much inconvenience to the operator, and 

 require to be carefully managed : on the left 

 side, the internal jugular vein itself, inclining 

 toward the median line below, slightly overlaps 

 the artery : the posterior layer of the sheath of 

 these vessels is a thin process of the fascia in- 

 terposed between them and the sympathetic 

 nerve, which descends vertically behind : se- 

 parated in like manner from the great vessels, 

 we find the inferior thyroid artery, which as- 

 cends in an obliquely serpentine course to the 

 lower angle of the thyroid body, and the recur- 

 rent laryngeal nerve, mounting (on a plane 

 deeper than that artery, internal to which it is 

 situated) toward the posterior part of the cn- 

 coid cartilage; the nerve is therefore very nearly 

 approached to the hindermost part of the tra- 

 cheal cartilages, and, on the left side, ascends 

 between them and the oesophagus, closely ap- 

 plied to the latter.* 



* The cardiac branches of the sympathetic, although 

 they require notice in connexion with the anatomy 

 of the large vessels, have little particular interest 

 in regard of the surgical operations, which are prac- 

 tised on these, and some account of thrm is there- 

 fore better appended in a note than blended with 

 the text. They are seldom or never distinctly seen 

 in operations; and the rule for their management 

 is but a part of the general piinciple (which ought 

 to be supreme in every surgical exposure ot an ar- 

 tery, and the neglect of which has been, I doubt 

 not, at the root of most unsuccessful issues) that 

 the disturbance of surrounding parts, and the de- 

 nudation of the artery, should both be in the very 

 least degree, which will permit the ligature of the 

 vessel to be accomplished. The cervical cord of 

 the sympathetic lies, as already mentioned, behind 

 the sheath of the cervical vessels, and presents 

 three ganglia, from which, and from the cord, va- 

 rious branches originate. Of these ganglia, the 

 uppermost has often above an inch in length, is of 

 tapering rounded form, and is situated in the pos- 

 terior pharyngeal region, on the second and third 

 vertebras : the second, of smaller size and incon- 

 stant occurrence, usually lies upon the inferior thy- 

 roid artery : the third, frequently contused with 

 the first dorsal ganglion, is deeply imbedded behind 

 the origin of the vertebral artery. From these 

 sources, assisted and reinforced by the pneumo- 

 gastric and other nerves, the cardiac branches ori- 

 ginate in a manner and succession which will be 

 described in a future article. (See SYMPATHETIC 

 NERVE.) In descending, they lie posterior to the 

 sheath, and the superior one internally to it, close 

 to the trachea, and, on the left side, to the oeso- 

 phagus. "When they approach the inlet of the 

 thorax, they comport themselves variously in regard 

 of the subclavian artery; sometimes passing behind 

 it, on each side, and furnishing twigs, which cross 

 its anterior surlace ; sometimes, on the contrary, 

 crossing its front by their main branches; and some- 

 times so dividing as to envelop the artery in an 

 abundant ncrvous^plexus. They are very iriegular ; 



The thyroid body belongs to this space by its 

 lateral parts, and, when of moderate develop- 

 ment, overlaps the carotid sheath. It consists 

 of symmetrical lobular halves, united by the 

 isthmus already alluded to : its lobes are pear- 

 shaped, on a section, the small end being up- 

 ward ; they are plump outwardly where the 

 fascia gives them a smooth envelope, but hol- 

 lowed inwardly where they adapt themselves 

 to the air-tube : the isthmus commonly con- 

 nects the lobes by their lower part only, by over- 

 bridging the trachea at about its second and 

 third rings : the apex of each lobe reaches to 

 the ala of the thyroid cartilage, covering the 

 fibres of the constrictor pharyngis, which arise 

 there, and receiving the superior thyroid artery 

 from the external carotid : the circumference of 

 the organ presents, then, upward a crescentic 

 sinus in which the angle of the thyroid 

 cartilage, the crico-thyroid membrane and 

 muscles, the cricoid cartilage, the first one, 

 two or three rings of the trachea are 

 seen : its thick outer margin, running from 

 the apex to the third, fourth, or fifth 

 ring of the trachea corresponds in that extent 

 to the carotid artery, which it more or less 

 overhangs, and below to the recurrent nerve of 

 the larynx; by the extremity of this border the 

 inferior artery reaches it from the thyroid axis ; 

 the inferior margin gives exit to veins, which 

 have already been mentioned, arid not infre- 

 quently receives by its middle a fifth artery 

 from the arch of the aorta or from the arteria 

 innominata. 



From the remarkable vascnlarity of this 

 body, so disproportionate to its volume and 

 apparent unimportance in the cecor.omy, it 

 readily falls into the heterogeneous group which 

 the German anatomists have named " Blood- 

 ganglia" (blut-knoten). Fiom the same circum- 

 stance, and from the probably vicarious func- 

 tion which it seems to discharge, it is extremely 

 liable to hypertrophy, the different forms of 

 which, attended by whatever structural change, 

 are confounded under the name of goitre or 

 bronchocele. From the account given of its 

 anatomy, the symptoms of its enlargement may 

 be surmised ; for it is obvious that a tumour, 

 so related to the windpipe and so checked in 

 its outward growth by tense aponeuroses, must 

 gravely afreet respiration. Overlapping the 

 common carotid arteries, the tumour derives 

 from them a strong and often visible impulse ; 

 and, over and above the jerk, which they com- 

 municate to it, a general thrill of distensive 

 pulsation, arising from its own almost erectile 

 vascularity, may be felt by the surgeon. Su- 

 perficial observation might fail to distinguish 

 such a tumour from carotid aneurism, but 

 anatomy establishes the diagnosis; for, in each 

 movement of deglutition, the diseased mass 

 accompanies the larynx, and is seen to rise and 

 fall in the neck. Attempts at extirpating 



but, in all cases, largely communicate with the re- 

 current nerves, behind the subclavian arteries, and 

 furnish numerous continuations, which descending 

 around the three great vascular trunks to the arch 

 of the aorta, hence prolong themselves to the base 

 of the heart. 



