IO4 



The Mouth 



at the front and back of the wound, and the judicious arrangement of 

 strips of waterproof strapping are now taking the place of the pins, the 

 use of which is apt to mark the lip with permanent scars. 



Supply. Below the region of the orbicularis the lower lip receives 

 the submental and inferior labial branches of the facial arteiy. The 

 coronary branches of the same artery pierce the orbicularis and form 

 a circle close beneath the mucous membrane. In operating for hare- 

 lip one suture should be passed beneath their cut ends. (There is no 

 superior labial artery : an upper lip which is long enough to need one 

 is an artistic defect.) The infra-orbital artery may help in the supply 

 of the upper lip, and the mental branch of the inferior dental in that 

 of the lower lip. The lymphatics pass to the submaxillary and to the 

 cervical glands. 



The nerves are derived from the terminations of the superior 

 maxillary and inferior dental trunks ; the mental branch of the inferior 

 dental also helps in the supply of the lower lip. 



Con 



igenital MacrostomaanJ Supernumerary 

 Auricular appendage. (FERGUSSON.) 



Macrostoma in a child six weeks old. (BLAND 

 SUTTON.) 



Development. The buccal cavity first appears as a depression 

 in the epiblast between the fronto-nasal process above, the superior 

 maxillary processes at the sides, and the mandibular plates (p. 105) 

 below. The mouth is then separated from the pharynx, but the par- 

 tition soon wears away at the region of the fauces. Sometimes the 

 hinder part of the mandibular fissure (M.F., p. 124) fails to be oblite- 

 rated ; a large mouth, macrostoma, then results. 



Hare-lip. The median part of the upper lip is formed by a flap 

 which descends, in connection with the fronto-nasal plate, from the 

 front of the cranium ; the lateral parts are developed from the cover- 



