GUIDE TO THE HEAD AND NECK 1575 



the supratrochlear, the temporal branch of the orbital or temporo-malar, 

 and the auriculo-temporal have been already dissected. The numerous 

 branches of the temporo-facial and cervico-facijil divisions of the facial nerve 

 are to be followed from the parotid gland to their distribution, care being 

 taken to note that the facial is the motor nerve of the buccinator muscle. 

 The infratrochlear branch of the nasal nerve is to be met with in the region 

 of the inner canthus, where it emerges from the orbit below the pulley of the 

 superior oblique muscle. The external terminal branch of the nasal nerve will 

 be found emerging between the lower border of the nasal bone and the upper 

 lateral nasal cartUage, after which it descends beneath the compressor naris 

 muscle to the tip of the nose. The infra-orbital nerve will be found emerging 

 through the infra-orbital foramen, but to display this nerve it is necessary 

 to divide the levator labii superioris muscle. Under cover of this muscle 

 the nerve communicates with the infra-orbital branches of the facial to form 

 the infra-orbital plexus. The inferior palpebral, nasal, and superior labial 

 branches of the infra-orbital nerve are to be followed out. The malar branch 

 of the orbital or temporo-malcir nerve will be found emerging through the 

 malar foramen in the malar bone. The long buccal nerve emerges from 

 beneath the anterior border of the masseter on to the buccinator, where its 

 branches communicate with the buccal branches of the facial nerve to form 

 the buccal plexus. The facial branches of the great auricular nerve ramify 

 in the integument over the parotid gland, and send offsets into the gland. 

 The mental nerve will be found emerging through the mental foramen in 

 the inferior maxilla, where it is under cover of the depressor anguli oris, and 

 in line with the interval between the two lower bicuspid alveoli. 



The chief arteries to be dissected are the faciai and transverse facial. The 

 facial arteiy is easily found, and is to be followed from the base of the inferior 

 maxilla to the region of the inner canthus. As many of its branches as pos- 

 sible are to be shown, more particularly the two coronary arteries. The 

 position of the facial vein on the outer side of the artery upon the body of the 

 inferior maxilla, in front of the masseter, is to be noted, and a lymphatic 

 gland is to be looked for in this situation. The facial vein will be found 

 to receive a fairly large tributary, the deep facial vein, which comes from 

 the pterygoid plexus, and emerges from behind the anterior border of the 

 ramus of the inferior maxilla and of the masseter muscle. The transverse 

 facial artery will be met with emerging from the anterior border of the 

 parotid gland, after which it crosses -the masseter immediately above Sten- 

 sen's duct. The infra-orbital and mental arteries admit of easy dissection. 

 The other arteries, though numerous, are for the most part of small size, and 

 for them the dissector is referred to the description given of them in the 

 text. 



The parotid gland is to be carefully dissected, and all its relations displayed. 

 The strong capsule which invests it, and which is derived from the deep 

 cervical fascia, is to be noted. The lower part of the gland is to be sho\\Ti 

 occupying the back part of the digastric triangle, where it is separated from 

 the submaxillary glajid by the stylo-maxillary ligament. Upon the gland, 

 but beneath the parotid fascia (anterior wall of the capsule), and also within 

 the gland, will be found the parotid l>-mphatic glands. Emerging from the 

 anterior border of the gland, and passing forwards over the meisseter muscle 

 on to the buccinator, the parotid or Stensen's duct is to be shown, with the 

 transverse facial artery above it, and the infra-orbital branches of the facial 

 nerve below it. The pars or glandula socia parotidis is to be shown accom- 

 panying Stensen's duct for a variable distance, and lying above it. The 

 branches of the facial nerve are now to be followed into the parotid gland, 

 cutting away the glandular substance in doing so. This will enable the 

 dissector to trace the trunk of the facial nerve to the stylo-mastoid foramen, 

 and to show its posterior auricular, digastric, and stylo-hyoid branches! 

 The auriculo-temporal nerve is also to be shown within the upper part of 

 the gland, and communications between this nerve and the temporo-facial 

 division of the facial, as well as between the great auriculcir nerve and the 

 cervico-facial division of the facial, are to be kept in view. The external 



