564 



DISSECTION OF THE FACE. 



upwards to the inner angle of the orbit to supply the muscles, 

 and to join the nasal and infractrochlear branches of the ophthalmic 

 nerve. 



The CERVICO-FACIAL is smaller than the upper trunk, and distri- 

 butes nerves to the lower part of the face and the upper part of the 

 neck. Its highest branches join the lowest offsets of the temporo- 

 facial division, and thus complete the network on the face. This 

 trunk, while in the parotid, gives twigs to the gland, and is united 

 three sets of with the great auricular nerve. The terminal branches distributed 

 branches. f rom ^ are bu^g^ siipramaxillary, and inframaxilkry. 



The buccal branches pass forwards towards the angle of the 

 mouth, giving offsets to the buccinator muscle, and terminate in the 

 orbicularis oris. On the buccinator they join the buccal branch 

 of the inferior maxillary nerve. 



The supramaxillary branches course forwards over the lower jaw 

 to the middle line, and supply the muscles of the lower lip and 

 chin. Beneath the depressor anguli oris these branches of the 

 facial join the offsets of the mental branch of the inferior dental 

 nerve. 



The inframaxillary branch lies below the jaw, and is distributed 

 to the platysma muscle, and forms communication with sensory 

 branches from the second and third cervical nerves. 



Dissection. The levater labii superioris muscle is now to be 

 cut through, and the upper part removed so as to expose the 

 terminal branches of the infraorbital nerve. 



The INFRAORBITAL NERVE (fig. 205) is the continuation of the 

 superior maxillary division of the fifth nerve. It emerges on the 

 face through the infraorbital foramen under cover of the levator 

 labii superioris, and at once divides into terminal branches which 

 radiate to the eyelid, the nose, and the upper lip. 



The palpebral branches are usually two small twigs which pass to 

 the lower eyelid. 



The lateral nasal branches are directed inwards, and supply the 

 skin of the side of the nose. 



The labial branches are three or four larger nerves, which, 

 descending to the upper lip, supplying the skin of the face between 

 the orbit and the mouth, as well as the mucous membrane of the 

 upper lip, and their ramifications, take part in the infraorbital 

 plexus, just described. 



Dissection. The depressor labii inferioris and anguli oris 

 muscles will next be removed so as to expose the mental nerve as it 

 issues from the foramen in the lower jaw. 



The MENTAL NERVE (fig. 205) is derived from the inferior dental 

 nerve within the lower jaw, and issues through the mental foramen 

 beneath the depressor anguli oris muscle. It gives an offset down- 

 wards to the skin of the chin, but the greater part of the nerve 

 ascends beneath the depressor labii inferioris muscle, to be dis- 

 tributed to the inner and outer surfaces of the lower lip. Its 

 branches communicate with the supramaxillary branches of the 

 facial nerve. 



Lower 

 division of 

 the nerve 

 bus also 



Bticcal to 

 corner of 

 mouth. 



Supra- 

 maxillary 

 between 

 mouth and 

 chin. 



Infra- 

 maxillary 

 to neck. 



Infra- 

 orbital 

 nerve. 



Palpebral, 



lateral 

 nasal and 



labial 

 brandies. 



Mental 

 nerve. 



