THE FACE. 



59 



artery may be encountered and may bleed. The temporal muscle arises not only 

 from the deep layer of the temporal fascia, but may also be attached anteriorly to 

 the inner surface of the zygoma, and in loosening it free bleeding from the deep 

 temporal arteries, branches of the internal maxillary, may be encountered. No 

 trouble need be expected in sawing through the anterior end of the zygoma, but care 

 should be taken not to injure the parotid duct, or the socia parotidis if it is present. 

 In making the division of the posterior end of the zygoma, one must guard against 

 opening the temporomaxillary articulation, for, when the head of the mandible is 

 back in the glenoid fossa, the capsule of the joint extends considerably in front of it. 

 Therefore, it is better to open the mouth and push the jaw on that side forward until 

 it rides on the eminentia articularis, then the anterior limit of the joint can be recog- 

 nized and avoided. Before one can reach the spur on the anterior extremity of the 

 infratemporal crest, the temporal muscle must be detached from the bone. The 



Processus coronoideus 



Processus 

 pterygoideus 



A. meningea 

 media 



N. mandibularis 



M. pterygoideus ex- 



ternus. Upper head 



turned down 



Masseter 



Temporalis 



Crista infratempo- 

 ralis 



Spur 



N. maxillaris 



A. infra-orbitalis 

 A. temporalis 

 prolundus 

 A. alveolaris 

 posterior 

 A. maxillaris 

 internus 



Zygoma 



FIG. 67. Operating through the pterygoid fossa. The skin with the zygoma and masseter have been turned 

 down. The coronoid process is divided and turned up. The upper head of the external pterygoid has been 

 detached and turned down. The maxillary nerve is in front of the pterygoid plate (processus pterygoideus) and 

 the mandibular nerve and middle meningeal artery just behind it. 



upper head of the external pterygoid muscle arises from the bone just below the 

 pterygoid ridge (infratemporal crest), and must be loosened from the bone to obtain 

 access to the nerves (see Fig. 67). 



The coronoid process rises almost as high as the infratemporal crest, and, there- 

 fore, in order to gain space it will be necessary to depress the jaw. Running upward 

 and inward over the internal pterygoid muscle, and passing just in front of the origin 

 of the upper head of the external, is the internal maxillary artery and pterygoid 

 plexus of veins. These vessels lie directly below the maxillary nerve as it crosses 

 the sphenopalatine fossa, and it is to be expected that free hemorrhage will accom- 

 pany the attempt to fish out the nerve. 



In operating in this region, one surgeon found the bleeding so severe as to 

 require the ligation of the external carotid artery. 



Intracranial operations are hardly ever done for maxillary neuralgia alone. The 

 mandibular and often the ophthalmic divisions are also usually affected in cases 

 requiring to be approached from the inside of the skull. 



