THE FACE. 7 



pterygoid ; and it gives the jaw a greater freedom of grinding 

 motion. 



The posterior margin of the ramus of the lower jaw 

 corresponds with a line drawn from the condyle to the 

 angle. In opening abscesses in the parotid region, the 

 knife should not be introduced behind this line for fear of 

 wounding the external carotid artery. Punctures to any 

 depth may be safely made in front of it. They are often 

 necessary where inflammation of the parotid gland ensues 

 after eruptive fevers, and runs on to suppuration. The 

 swelling, tension, and pain are most distressing. Owing 

 to the fibrous framework of the gland, the matter is not 

 circumscribed, but diffused. One puncture is not enough. 

 Three or more may be requisite. The blade of the knife 

 should be held horizontally, so as to be less likely to injure 

 the branches of the facial nerve. We are not to be dis- 

 appointed if no matter flows. The punctures give relief, and 

 matter will probably exude the next day. 



12. Parotid duct. A line drawn from the bottom of the 

 lobe of the ear to midway between the nose and the mouth 

 gives the course of the parotid duct. Opposite the second 

 upper molar, the duct opens by a papilla into the mouth. 

 The branch of the facial nerve which supplies the buccinator 

 runs with the duct. 



13. Temporal and facial arteries. The pulsation of 

 the trunk of the temporal artery can be felt, between the 

 root of the zygoma and the ear. This should be well known 

 to and used by chloroformists. It is also a convenient pulse 

 to feel in a sleeping patient. The facial artery can be dis- 

 tinctly felt as it passes over the body of the jaw at the 

 anterior edge of the masseter ; again near the corner of the 

 mouth close to the mucous membrane : and, lastly, by the 

 side of the ala nasi, up to the inner side of the tendo oculi. 

 By holding the lips between the finger and thumb the 

 coronary arteries are felt under the mucous membrane. The 

 facial vein does not accompany the tortuous artery, but runs 

 a straight course from the inner angle of the eye to the front 

 border of the masseter, just behind the artery. 



