Abnormality of the philtrum Narrow philtrum 2012-05-01T10:38:12Z HP:0011829 UMLS:C4021115 Philtrum, Narrow Decreased transverse dimension of philtrum Although congenital sinuses of the lips generally occur in the lower lip, in rare instances they may appear in the philtrum of the upper lip, commonly close to the insertion of the columella. Thin philtrum Decreased width of philtrum Distance between the philtral ridges, measured just above the vermilion border, more than 2 standard deviations below the mean. Alternatively, an apparently decreased distance between the ridges of the philtrum. Decreased breadth of philtrum Decreased horizontal dimension of philtrum