1054 DISSECTION OF THE HEAD AND NECK. 



tebral and internal mammary arteries, the thyroid axis, from which arise 

 the inferior thyroid giving off the ascending cervical artery, the supra- 

 scapular artery, and most frequently the transverse cervical dividing into 

 the superficial cervical and posterior scapular ; lastly, there are the deep 

 cervical and superior intercostal arteries coming off either as a single trunk 

 or separately (p. 3 66). The frequent origin of the posterior scapular artery 

 from the third part of the subclavian artery and other varieties will here re- 

 quire to be attended to (p. 372). The trunk of the sympathetic nerve is to 

 be dissected, with its three cardiac and its other branches, as high as the first 

 cervical nerve (p. 688) ; and the recurrent laryngeal branch of the vagus 

 nerve is to be found between the gullet and trachea, and traced up to the 

 larynx (p. 622). 



6. Superficial Dissection of the Face. In proceeding with this region, the 

 dissectors ought to expose in concert the superficial muscles of the face on 

 one side, keeping only the principal blood-vessels and nerves. They ought 

 likewise to make a more detailed exposure and dissection of these vessels 

 and nerves on the other side, for which purpose the superficial muscles 

 must be in some measure sacrificed. If this method cannot be followed 

 in concert, each dissector must display as much as possible all the parts 

 on his own side, in which case he will do best to begin with the superficial 

 muscles. 



To exhibit the superficial muscles of the face, the skin is to be reflected 

 from the middle line, from which one or two such transverse incisions as 

 shall seem necessary are to be directed outwards. It is most convenient to 

 begin with the orbicularis palpebrarum muscle, removing the skin from the 

 circumference to the margin of the eyelids, and dividing it along these 

 margins (p. 171). The muscles between the eye, nose and upper lip may 

 then be exposed, the principal of which are these : the compressor naris, 

 the levator labii superioris alseque nasi, the levator proprius labii superioris, 

 and the zygomatici, more deeply the corrugator supercilii, the levator anguli 

 oris, the pyramidalis nasi continued from the frontalis, the dilatator naris, 

 <fec. Below the mouth the depressor anguli oris and depressor labii inferioris 

 will be seen. A more complete view of the orbicularis oris may be obtained 

 by dissecting it from the inner aspect of the lips ; and the levator menti is 

 best displayed by making an incision down to the bone in the middle line, 

 and dissecting outwards. 



To expose the nerves and blood-vessels of the face, the sl<in may be reflected 

 as stated above from the middle line outwards. The surface of the parotid 

 gland is to be cleaned, and search made for the branches of the facial nerve 

 as they emerge from underneath its upper and anterior margins (p. 614). The 

 duct of the parotid gland, and the transverse facial artery, are also to be 

 dissected (p. 354). The branches of the facial nerve are to be followed for- 

 ward, and, as far as possible, their connections with the infraorbital, buccal 

 and inferior labial branches of the fifth nerve are to be traced. Let the 

 dissector cut the superior attachment of the levator proprius labii supe- 

 rioris muscle, and, dissecting down upon the infraorbital foramen, follow 

 out the distribution of the infraorbital nerve and artery emerging from 

 it (pp. 602 and 357). Let him also cut carefully down upon the mental 

 foramen, and follow out the inferior labial nerve and artery emerging thence 

 (p. 608). 



The facial artery and vein with their branches are to be dissected out 

 from the point to which they have been previously traced at the border 

 of the jaw. The principal branches of the artery, such as the inferior labial, 



