NECK. 



577 



which spring from the external one, viz. the 

 occipital passing obliquely toward the mastoid 

 process, under cover of the posterior belly of 

 the digastric, and hooked round by the hypo- 

 glossal nerve; the muscular, which is not in- 

 variably present, inclining outward to the 

 sterno-mastoideus ; the lingual and facial (di- 

 vided by an imaginary prolongation of the 

 cornu of the os hyoides from the superior thy- 

 roid) entering the digastric space, the former 

 transversely by running along the cornu of 

 the os hyoides between the hyo-glossus and 

 middle constrictor, the latter more obliquely 

 ascending; and the pharyngeal artery deeply 

 running upward beside the pharynx. To 

 all these branches a more particular descrip- 

 tion has been given in a previous article, 

 than would be suitable to the present one; 

 and to that the reader is referred for the 

 details of their distribution. (See CAROTID.) 

 The jugular vein descends externally to the in- 

 ternal, as to the common carotid, the vagus 

 lying, as in the lower region of the neck, be- 

 twe^p. the two vessels and rather behind them. 

 The vein receives several branches, in travers- 

 ing this triangle, from the larynx and tongue, 

 and usually the facial vein : all these, since 

 they come from within, must cross in front of 

 the artery, and sometimes form an intricate 

 plexus, which much embarrasses an operator. 

 In front of the sheath descends, with a slight 

 inward obliquity, the branch of the lingual 

 nerve, which at the lower part of the space, 

 and while lying over the vein, forms a reversed 

 arch of communication with the cervical plexus, 

 whence branches are distributed to the sub- 

 hyoid muscles. The integuments and pla- 

 tysma require no particular notice ; their veins 

 and nerves have already been described ; 

 among the former must be reckoned the an- 

 terior jugular; the space contains a great num- 

 ber of lymphatic glands, a long chain of which 

 (glandultE concatenate) lies along the outer 

 side of the sheath of the vessels, while some 

 also lie about the thyroid and lingual arteries 

 on the inner side of the sheath. The surgical 

 relations of this space are chiefly confined to 

 the arteries : ligature of the common carotid 

 or of either of its branches may easily be per- 

 formed here, since the vessels lie under a much 

 less thickness and variety of parts than below. 

 A vertical incision falling on the point of inter- 

 section of the orno-hyoid and sterno-mastoid 

 muscles, and successively dividing the super- 

 ficial fascia (in which the platysma and cuta- 

 neous nerves are contained) and the cervical 

 aponeurosis (a single layer, as it stretches 

 across the space, but, of course, double where 

 it encloses the sterno-mastoid,) exposes the 

 sheath of the vessels, the veins which trans- 

 versely cross its arterial portion, and the de- 

 scendens noni which runs on the part of its 

 wall corresponding to the jugular vein: and 

 here, as he might open the sheath lower or 

 higher, the surgeon would expose the common 

 carotid or its branches; and, in remembering 

 that the internal (so named from its distri- 

 bution only) lies at first external to and behind 

 the other, he would be able to isolate and 



VOL. lit. 



secure either of these at his option. In any 

 attempt to tie the branches of the external 

 carotid, a clear notion of their respective re- 

 lations to the hyoid bone is of indispensable 

 necessity ; and, in ascending toward the di- 

 gastncus, it must be remembered that the 

 lingual nerve crosses the carotid sheath but 

 just below the border of that muscle, and that 

 it and the facial vein are consequently exposed 

 to injury. Attempts at suicide by cutting the 

 throat seldom succeed ; the incision is usually 

 made closely either above or below the hyoid 

 bone; in the former case entering the digastric 

 regions, and dividing, with the muscles of the 

 tongue, the lingual and perhaps the facial 

 artery ; in the latter case, traversing the thyro- 

 hyoid membrane, penetrating the pharynx, per- 

 haps implicating the epiglottis, dividing the 

 thyroid artery, and very rarely reaching the 

 external carotid. The mode of searching for 

 these vessels must vary according to circum- 

 stances, but, in all essential particulars, may 

 readily be deduced from their anatomy. 



4. The postero-superior triangle is a large 

 space of singularly little interest, having its 

 inferior boundary fixed by the omo-hyoid mus- 

 cle, its anterior by the diagonal which inter- 

 sects this, its posterior by the edge of the trape- 

 zius, and its apex by the mastoid process. It 

 contains, below, a part of the brachial plexus 

 (the anterior branches, namely, of the fifth and 

 sixth cervical nerves, which directly pass be- 

 neath the omo-hyoid muscle into the adjoining 

 inferior triangle,) the whole of the cervical 

 plexus and many of its branches, the spinal 

 accessory nerve, obliquely crossing from the 

 sterno-mastoid to the trapezius, which it enters 

 near its clavicular insertion, and some rami- 

 fications from the arteria transversalis colli, 

 which, under the name of superficial cervical, 

 ascend in the space, supply its cellular mem- 

 brane and Ivmphatic glands, and ultimately 

 inosculate with descending twigs from the 

 occipital. The pre-vertebral fascia covers its 

 deep parts; the common cervical extends be- 

 tween its borders; the platysma myoides exists 

 as a covering for it only in its lower part. 



5. The poxtero-inforior triangle, (that of the 

 subclavian artery,) is one of manifold impor- 

 tance. The well-known lines of the omo-hyoid 

 and clavicle limit its area above and below, 

 the former dividing it from the space last con- 

 sidered, the latter from the pectoral region ; 

 intersecting the omo-hyoid, our imaginary di- 

 agonal, as it stretches from the centre of the 

 sterno-clavicular joint upward and outward, 

 bounds it internally, and constitutes an arbitrary 

 but most useful separation between the space, 

 exclusively appropriated to the subclavian artery 

 with its branches and that internally adjoining 

 it, (the antero-inferior.) which is the proper ter- 

 ritory of the carotid. The parts forming its 

 deep or posterior wall are, the transverse pro- 

 cesses of the lower cervical vertebrae and head 

 of the first rib, the outer edge of the longus 

 colli and the broad lower part of the scalenus 

 posticus: its inferior wall presents the upper 

 surface of the first rib, and within the curve 

 of this bone a part of the upper inlet of the 



2 P 



