From: Clinical photographic observation of plantar corns and callus associated with a nominal scale classification and inter- observer reliability study in a student population
Grade 1
Grade 2
Grade 3
Grade 4
Grouping
59
35
6
Females (all)
40
29
8
12
Males (all
53
33
7
All combined
0
<10 years
24
10
2.5
1.6
<20 years