الفهرس 
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Abstract
Building a biological profile of an individual is a fundamental task of forensic expert. It assists in determining sex, age, stature, and race of individuals to reduce further conclusive tools as DNA.
Human foot is a complex structure that is unique to each individual. In the crime scene, any foot-related evidence may be useful in identity determination and sometimes forensic expert may be confronted with just a foot to build the biological profile of unknown persons. The foot evidence may be recovered as partial or complete footprints or mutilated remains of feet in mass disasters.
The objective of the current work was to study the footprint and foot outline in two different populations (Egyptian and Malaysian) and assess dimensions, individual characteristics, pattern and ridge density of the foot and its relation to sex and population difference. Moreover, the current study aimed to formulate equations for determination of stature and bodyweight from dimensions of footprint and foot outline for each studied population.
The study was conducted on two hundred adult volunteers. They were divided into two equal groups; the first group included one hundred adult Egyptians (50 males and 50 females) and the second group included one hundred adult Malaysians (50 males and 50 females). All subjects were randomly selected with age ranging from 18-30 years.
After approval of ethics committee, the footprints were collected from each subject using an inkless shoe print kit. In addition, the foot outline (a line tracing around the outer margins of the fleshed foot) was also drawn as close to foot as possible, and then various parameters were measured.
The metric parameters (in cm) were taken from footprint and foot outline as follows: Maximum foot length (MFL), Foot length measurements (T1-T5), Foot breadth at the ball (FBB), Foot breadth at heel (FBH), Big toe dimensions (BTW and BTL). Moreover, two indices were calculated from footprint and foot outline measurements which are Heel/ball Index (HBI) and Foot index (FI).
In addition, many individual characteristics of the collected footprint were assessed and analyzed statistically using regression analysis:
Foot was classified based on relative morphological length of the toes into: Fibularis, Tibularis, intermediate and Medularis.
Toes inter-distance was measured and classified into: wide, medium and narrow.
Position and number of phalangeal marks, and the count of humps were examined.
Chippaux-Smirak index (CSI) was calculated and used to classify the foot according to the morphology of arch region.
Besides, the footprints were examined using a magnifying lens and the pattern of hallucal area of the foot was classified using the classification of Federal Bureau of Investigation system (FBI)
In addition, ridge density was counted from four different areas of footprint (upper portion of medial border of big toe, the medial ball, the lateral ball and the central prominent part of the heel).
The study revealed the following results:
Footprint anthropometric measurements:
• In both studied populations, males tended to have significantly larger length and breadth footprint measurements than females in both feet (p<0.001), but the calculated footprint indices (HBI and FI) showed no significant difference between males and females (p=.826 and .378 respectively).
• On the other hand, all length measurements of footprints in Egyptians were significantly larger than Malaysians regardless of the sex and the side (P<0.001). However, breadth measurements of footprints revealed that FBB showed no statistically significant difference between the two studied populations (p=.134), whereas Egyptians tended to have significantly larger FBH measurements than Malaysians (p<0.001). Moreover, no significant difference was observed between the two studied populations as regards big toe dimensions, where p=.208 for BTW and p=.085 for BTL. Besides, Egyptians had significantly higher HBI (p<0.001) and lower FI (p=.002) than Malaysians among both sexes in both feet.
Foot outline anthropometric measurements:
• As regards sex, all foot outline length measurements of males exhibited significant higher values than females (p<0.001) in both feet and among both populations. In addition, the foot outline breadth measurements of both feet in males showed significantly higher values than females where p<0.001 and p=.01 for FBB and FBH respectively among both studied populations. The indices of the two feet showed no significant difference between both sexes among Egyptians and Malaysians (p=.21 for HBI and p=.833 for FI).
• Regarding ethnicity, all foot outline measurements taken from right and left feet differed significantly between Egyptians and Malaysians. Egyptians were more likely to have larger length and breadth measurements compared to Malaysians (p<.001) in both sexes. However, the calculated indices (HBI and FI) showed no statistically significant difference between the two populations. (p=.136 and p=.592 respectively).
Anthropometric measurements taken from footprints and foot outline were also used to build up regression equations for determination of stature and bodyweight. As there was no significant difference between measurements of left and right foot, right measurements were used to build up the models.
Two statistical methodologies were used to assess the accuracy of determination of stature and bodyweight from obtained footprint and foot outline measurements; Random forest (RF) and linear regression analysis.
The whole sample of each group was divided into two sets: training set and test set. The training set was used to build up a model, while the test set was to validate the built model.
A full RF model was built up on each population. Then, a reduced RF model was built using the most important predictors. No statistically significant difference between errors obtained from full and reduced models was observed, so, the reduced model was used and validated on the test set.
To produce easily written equation, multiple regression models were built using the important predictors identified by full RF model.
Using R2, the accuracy of stature determination from footprints was 64% in Egyptians and 75% in Malaysians, while the equations built to determine bodyweight from dimensions of footprints showed accuracy about 40% in Egyptians and 50% in Malaysians.
Moreover, the study formulated two regression equations for stature determination using the foot outline measurements in each population separately with accuracy 67% for Egyptians and 73% for Malaysians. While the estimated accuracy from equations built to determine bodyweight from foot outline measurements was about 46% for Egyptian population and 52.9% for Malaysian population.
Individual features of footprints
• The most frequent foot type was Fibularis type in both feet of Egyptian males (52% in right foot, 50% in left foot) and also in left foot of Egyptian females (46%), while Tibularis type was the most frequent type in the right foot of Egyptian females (48%). In Malaysian population, the frequency of Fibularis type was the highest in both feet of males (64% in right foot, 68% in left foot) and females (64% in right foot, 72% in left foot).
• Regarding toes inter-distance, the percentage of medium t1-t2 inter-distance was found to be higher in both sexes of the two studied populations. For t2-t3 inter-distance results showed that narrow inter-distance was the most prevalent one in Egyptian and Malaysian populations in both sexes. As regards t3-t4 inter-distance, narrow inter-distance was the most frequent in Egyptians, while in Malaysian population, the medium inter-distance was the most frequent. Medium inter-distance between t4-t5 was the commonest finding in all groups.
• The phalangeal marks which are created only by one toe was the most frequent finding in all groups and they were created by the big toe in most of the prints of Egyptians and Malaysians.
• Three humps was the commonest finding in Egyptian males (52% in right foot and 62% in the left foot), while two humps was the most frequent in Egyptian females (60% in right foot and 56% in left foot). On the other hand, in the Malaysian sample, the results of males showed that two humps were found more often (54% in right foot and 56% in left foot), but in females three humps were found more often (56% in right foot, 58% in left foot)
• As regards CSI, the most frequent variant in both sexes of the two studied populations was intermediary variant. The frequency of flat foot was higher in males than females in Egyptians and Malaysians.
• Using regression analysis, it was observed that among morphological features of footprints, males appeared to have significant lower t3-t4 inter-distance (p=.012) and higher CSI (p=.004) among the two studied populations and in both feet. Among Egyptians, a 14% increase in the number of humps was observed in males (p<0.001). While in Malaysians, humps count in males was equal or less than that found among females (p=0.56). Compared to Malaysian females, Malaysian males were found to have significantly fewer phalangeal marks (p=.003), however no significant difference was observed among Egyptians (p=.123)
• As regards ethnicity, all footprints characteristics differed significantly between Egyptians and Malaysians except CSI. Malaysians tended to have wider toes inter-distances, Malaysian females tended to have significantly more humps (p=.001) and phalangeal marks (p<0.001) compared to Egyptian females. While Malaysians males tended to show relatively fewer humps than Egyptian males (p=.034) and insignificantly different number of phalangeal marks (p=.415).
The footprint pattern and ridge density:
• The current study revealed that La pattern was predominant in Egyptian males in both feet (40% in right foot and 42% in left foot), whereas in females, the most frequent patterns were La in right foot (40%) and Ww in left foot (34%).
• At the same time, La footprint pattern was predominant in Malaysian males (56% in right foot and 50% in left foot) and females (78% in right foot and 72% in left foot)
• Although the Loop pattern was the predominant pattern among both Egyptians and Malaysians, the odds to have Whorl pattern were significantly higher among Egyptians than Malaysians (p=0.002) with no significant difference observed between males and females (p=.556) or between both feet (p=.418).
• The mean footprint ridge density was significantly higher among females than males in all designated areas (p < 0.01) in both feet. No bilateral asymmetry was apparent in the analyzed areas.
• Differences in footprint ridge density between the two populations were evident among both sexes in all studied areas (p<0.001) except medial ball area (RD2).