THE PTERYGO-MAXILLARY REGION. 57 



the masseter muscle, the tendinous intersections of which 

 are very evident during its action. If the finger be 

 passed into the mouth, the superior border of the lower 

 jaw, the internal aspect of its ramus, and its anterior 

 border can be felt; and if the jaws are apart, its coro- 

 noid process; the mutual relations of which should be 

 carefully noticed. 



Dissection. The superficial dissection of the face being 

 completed, and the facial nerve, the transverse facial 

 vessels, with the duct of the parotid, cut and turned 

 forwards, that portion of the parotid which lies upon the 

 masseter is to be turned back towards the ear, and the 

 masseter itself exposed. Two sets of fibres will be seen 

 the anterior forming the greater bulk of the muscle, 

 and behind and below these some oblique fibres, which 

 are inserted beneath the anterior. The origin of these 

 fibres is on the under and inner surface of the zygomatic 

 arch. It is to be noticed that the zygoma is entirely 

 subcutaneous. Next, the extremities of this process are 

 to be divided with a saw, and the included portion of 

 bone with the origin of the muscle turned downwards 

 upon the ramus of the jaw, noticing the attachment of 

 the temporal fascia to its upper border, and taking care 

 not to divide the masseteric nerve and artery, which 

 enter the under and upper aspect of the masseter through 

 the sigmoid notch, or to injure the external lateral liga- 

 ment of the temporo-maxillary articulation. The ramus 

 of the jaw is next to be divided transversely, about 

 three-quarters of an inch below the notch, taking care 

 not to injure the inferior dental vessels and nerve which 

 enter the bone on its inner surface. The neck of the 

 condyle should then be nipped through, and the portion 

 of bone (including the coronoid process and a part of 



