Development of Lip 105 



ings of the superior maxillary processes, which, extending inwards, 

 are eventually fused with the descending flap at a short distance from 

 the median line. 



If a unilateral arrest of development take place, a single hare-lip 

 results ; if the arrest be symmetrical, 

 the cleft is double. The labial cleft 

 is thus to the side of the median line, 

 not in it, as it is in the hare. The 

 cleft may extend into the nostril ; or 

 may be represented by a mere notch 

 or depression at the border of the lip. 

 Sometimes a small triangular gap is 

 found continuous by its apex with a 

 vertical linear cicatrix, as if Nature 

 herself had attempted a plastic opera- 

 tion with partial success. Hare-lip 

 may be hereditary, several members Double hare - H t % S? lla attached to 

 of the same family being disfigured 



by it. Often it is associated with cleft palate, and the median piece of 

 the lip may be attached with the inter-maxillary bone to the projecting 

 nasal septum. 1 In double hare-lip the inter-maxillary bone should 

 contain the four incisors, but more often it contains three, or two only. 





Mr. Pitt's case of Median Hare-lip. Notch in pr?cess descend j ng to 



form median part of lip ; a 

 deepening of this notch gives 

 median hare-lip. 



Fergusson taught that the lateral incisors were then lost in the cleft, 

 but, from development (p. 17), this explanation does not suffice. 



The median part of the lip descends as a bifid process, and if the 

 gap between its lateral nodules be exaggerated, whilst their outer 



1 From The Surgical Diseases of Children, Cassell & Co. 



