570 



NF.CK. 



the prolongation which it sends downward on 

 the scaleni; and which partly fixes itself to the rib 

 around the attachments of those muscles, partly 

 extends itself, as a strong infimdibulum on the 

 brachial plexus and subclavian vessels. From 

 this their fascial sheath an horizontal slip 

 detaches itself and passes forward to the pos- 

 terior surface of the clavicle, where it fixes 

 itself by two laminae ; the upper of these is 

 inserted just above the attachment of the sub- 

 clavius muscle, while the lower is continued 

 into the sheath which that muscle derives from 

 the coraco-costal fascia. The horizontal pro- 

 cess separates the cavity of the axilla from the 

 lower triangle of the neck, and the vaginal 

 prolongation, contracting as it descends, be- 

 comes lost in the sheath of the axillary vessels. 

 Finally, as these various layers of fascia at- 

 tach themselves about the inlet of the thorax, 

 (the sub-hyoid part of the cervical aponeurosis 

 in front, and the pre-vertebral behind,) they 

 are connected to one another and to the large 

 vascular and mucous canals, which traverse 

 that passage, by certain horizontal processes of 

 fibrous membrane, which constitute together a 

 kind of diaphragm, or cervico- thoracic septum. 

 Viewed from below this would seem a vaulted 

 membrane, overarching the tops of the pleu- 

 ra, and giving infundibular passage to the 

 great arterial and venous trunks and to the 

 trachea ; viewed from above it would present 

 the various deep implantations of the cervical 

 fascia, and a surface without aperture or breach 

 of continuity, prolonging itself in several di- 

 rections round the canals, which it thus indi- 

 rectly transmits. The obvious use of these ar- 

 rangements is to supply adequate resistance to 

 the atmospheric pressure, which, were it not 

 borne ofTby the tension of these fascia?, would 

 at each inspiratory effort tend to flatten the 

 trachea, or to rush through the upper strait of 

 the thorax. Allan Burns, who in this country 

 first drew attention to the importance of the 

 cervical fascia, carefully illustrates its func- 

 tions in health, and the inconveniences which 

 accompany its destruction. (Op. cit.) 



III. REGIONAL DISTRIBUTION AND SUR- 

 GICAL ANATOMY Or THE NECK. 



The posterior parts of the neck having been 

 described in a previous article (see BACK), the 

 present will be restricted to an account of its 

 anterior aspect. 



The cervical vertebrae (by their bodies, inter- 

 vening nbro-cartilaginous discs, and transverse 

 processes), together with the anterior and la- 

 teral vertebral muscles, already described, com- 

 pose the skeleton and supporting fabric of this 

 region : the anterior fibres of the trapezii, as 

 they descend on either side to the inner edge of 

 the acromio-clavicular arch, form its lateral 

 boundaries ; the larynx and trachea (covered 

 by their own extrinsic riband-like muscles, and 

 partly covering the pharynx and oesophagus) 

 separate the nearly symmetrical halves of the 

 neck by constituting along its median line a 

 marked columnar relief, in the recesses beside 

 which lie the great cervical vessels ; the base 

 of the skull and the oblique line of the jaw are 



the upper limits of the region ; the clavicle 

 (just behind which the great vascular and ner- 

 vous trunks of the upper extremity course) 

 bounds it below ; the skin, the platysma 

 myoides (in its cellular covering), and the cer- 

 vical aponeurosis are stretched across it as ge- 

 neral investments ; while the last-named fascia 

 ensheathes the various parts by special pro- 

 cesses from its deeper surface. 



Thus, in general terms, the structure of the 

 neck may be described ; but, for the more pre- 

 cise and particular account, which the impor- 

 tance of its anatomy renders necessary, a 

 division of it into spaces of small extent is 

 convenient. The arrangement, which I propose 

 following, differs but little from that usually 

 adopted, and, perhaps, somewhat exceeds it in 

 precision. 



The upper limits of the neck having been 

 stated as the oblique line of the jaw and the 

 base of the skull (which parts, as we shall pre- 

 sently see, are brought into relation by the 

 attachments of the constrictor pharyngis supe- 

 rior), our highest region has in that direction 

 these parts for its boundary, and extends below 

 as far as the curve of the muscle, from which it 

 is named the digastric space. 



A small space that can hardly be referred to 

 the digastric, from which it is separated by the 

 vaginal process of the temporal bone, and by 

 attachments of fascia, and which, from the im- 

 portance of its contents, deserves careful consi- 

 deration, is the posterior phari/tigeul ; it lies 

 closely beneath the base of the skull, (from the 

 vaginal process to the median line) between the 

 pharynx and spine, and includes the carotid, 

 jugular, and condylic canals, and the organs 

 traversing them. 



If now an oblique line be carried across the 

 neck, from the sterno-clavicular articulation to 

 the tip of the mastoid process, it divides, as a 

 diagonal, the remaining quadrilateral surface of 

 the neck into two triangles ; an anterior one 

 having its apex at the sterno-clavicular joint, 

 and its base along the posterior belly of 

 the digastric muscle ; a posterior one, having, 

 its base at the inner two-thirds of the cla- 

 vicle, its apex at the mastoid process, its 

 posterior side formed by the trapezius, its an- 

 terior border defined by the imaginary line 

 which demarks it from the anterior triangle. 

 The omo-hyoid muscle, in its reflected course, 

 crosses both these triangles, subdividing them ; 

 and since the angle of its bend falls just on the 

 line of their separation, and since it proceeds 

 from behind the outer third of the clavicle to 

 the body of the hyoid bone, it acts as a second 

 diagonal in the neck, dividing each into an 

 upper and a lower triangular space. These 

 four triangles will be described in detail ; and 

 since the sterno-mastoid (which is too sub- 

 stantial to be treated as a mere boundary-line) 

 enters into all of them, and has to parts of each 

 relations of the extvemest practical importance, 

 some separate, chiefly recapitulatory, consi- 

 deration will be given to its relative anatomy. 

 Finally, to ensure for the organs of the median 

 line the consideration they require (the useful- 

 ness of which mainly depends on their being 



