Distribution and Uniqueness in the Pattern of Lip Prints

Introduction Lip prints are the characteristic pattern of wrinkles and grooves on the labial mucosa. Lip prints can be classified into various patterns and can be used for personal identification as they are unique and do not change during the life of a person. Cheiloscopy is a forensic investigation technique that deals with the identification of humans based on lip traces. Objectives This study aimed to investigate the distribution of lip print patterns, to assess gender differences, and to calculate the lip score using a weighted value scoring system. Material and methods A cross-sectional study was carried out in the Department of Anatomy, All India Institute of Medical Sciences (AIIMS), Guwahati, India, from May to October 2023, after getting approval from the Institutional Ethics Committee (IEC). A total of 200 individuals (100 males and 100 females) were included in the study. Each lip print was divided into four quadrants. In each quadrant, up to 14 grooves were marked from the midline, and the pattern of each groove was observed. Each pattern was given an Arabic numeral score. Weighted values were given for the grooves in descending order from 15 to 1 with reference to their position from the midline of the lip print. The product of the Arabic numeral score of the groove and the weighted value of the groove is the lip line score. The sum of the lip line scores was calculated. Results The most common pattern observed in the present study is type II, with 3,816/12,000 (31.8%), followed by type I' with 3,146/12,000 (26.21%), type I with 1,865/12000 (15.54%), type III with 1,491/12,000 (12.42%), type IV with 1,133/12,000 (9.44%), and type V with 549/12,000 (4.5%). The mean total lip score is 1,467.68 (1,486.41 in males and 1448.96 in females). Conclusion Lip prints are unique and useful for personal identification, as the lip score in various quadrants and the total lip score are different for different individuals.