434 ANATOMICAL TECHNOLOGY. 



the skin is to be mounted, this should "be the only incision, and the 

 skin must be dissected from the mandible as well as from the rest 

 of the head. But if, as is more often the case, the skin is not to be 

 preserved, while the vessels and nerves of the neck are to be exam- 

 ined, make a corresponding incision from the angle of the mouth 

 upon the opposite side. 



In all subsequent operations, unless otherwise stated, both sides 

 are to be treated alike. 



Dissect t!ie skin from the maxilla as far as the ventral margin 

 of the orbit and cut the nasal cartilages. Dissect the skin from the 

 nasal and frontal regions, including the dorsal and ventral lids but 

 leaving the third lid, Membrana nictitans, attached to the ball. 

 Remove the skin from the rest of the head, dividing the meatus 

 audiiorius close to the head. The parotid gland (Fig. 87) will be 

 removed with the ear, but tiie submaxillary, of a darker color, will 

 remain with the head. Reflect the skin from the cervical muscles 

 for about 2 cm. caudad of the crista lambdoidalis. 



With the arthrotome, dissect the origin of the M. massetericus 

 from the zygoma, noting that its cephalic and caudal borders are 

 strengthened by tendinous bands which must be cut (§ 596, 19). 

 Push a nipper blade between the eyeball and the cephalic root of 

 the zygoma, and nip the latter as close as possible to the maxilla. 

 Then nip the caudal root at the angle between the transverse and 

 longitudinal parts of the zygoma, just laterad of the Fossa glenoi- 

 dalis ; remove the zygoma with the bone scissors. 



Grasp the lateral aspect of the eyeball with the forceps, and 

 rotate it mesad so as to expose its attachments, by the muscles and 

 N. opticus, to the bottom of the orbit ; cut the attachments with 

 scissors, leaving the Mb. nictitans connected with the ball. If the 

 eyes are to be studied or preserved, mark them right and left by 

 numbers or tags ; the proper position is always indicated by the 

 Mb. nictitans ; see Chap. XI. 



Slightly ventriduct the mandible and move it from side to side 

 so as to indicate the position of the Arthron temporo-mandibulare. 

 Usually the capsule has been opened already in nipping the caudal 

 root of the zygoma. If not, it is to be cut while on the stretch by 

 inserting the arthrotome, and cutting until separation is complete 

 on that side. 



Dissect the M. temporalis from its cranial origin, and then 

 from its insertion upon the Processus coronoideus of the mandible. 



