47 Anatomy Applied to Medicine and Sutgery. 



Excision of one-half of the lower jaw is performed 

 through an incision starting in the middle line, just below 

 the lip, which is not divided. The incision is continued 

 along and immediately beneath the lower border of the 

 bone, and then upwards, behind the angle, to a point imme- 

 diately below the lobule of the ear. The integument is push- 

 ed up and the muscles separated from the external surface 

 of the bone by means of a periosteal elevator ; the buccal 

 mucous membrane is now severed at its junction with the 

 alveolus, the bone is sawn through near the symphysis 

 and the anterior end of the portion to be removed is drawn 

 outwards, the attachment of the mylo^hyoid is then divid- 

 ed, the internal pterygoid is separated by means of an ele- 

 vator and the inferior dental nerve and artery severed. 

 The jaw is now depressed, thus bringing into view the 

 coronoid process, to which is attached the temporal mus- 

 cle, and this muscle is cut through with curved scissors. 

 The external pterygoid is next exposed and detached, the 

 articulation is opened and the ligaments divided without 

 any twisting of the bone, since such twisting might bring 

 the internal maxillary artery in contact with the neck of 

 the bone so that it could be wounded. The remaining 

 tissues, i.e., the stylo-maxillary and the pterygo-maxillary 

 ligaments are divided and the jaw removed. The struc- 

 tures in danger of being wounded and which must be 

 avoided during the operation, are : The facial nerve, the 

 internal maxillary artery and tempero-maxillary vein, 

 the auriculo-temporal nerve, the external carotid artery, 

 the gustatory nerve, and the salivary glands. 



