Ra. Martin et al., ABSENCE OF THE LATERAL PHILTRAL RIDGES - A CLUE TO THE STRUCTURAL BASIS OF THE PHILTRUM, American journal of medical genetics, 65(2), 1996, pp. 117-123
This study compares philtral development in the normal fetus with phil
tral development in specimens lacking normal philtral landmarks. Disti
nct differences in the structure of the upper lip were discovered betw
een the two groups using a histological comparison. A new mechanism fo
r the structural basis of the philtrum is proposed on the basis of the
se differences. (C) 1996 Wiley-Liss, Inc.