Legend
1. heel perioplium
2. bulb
3. frog
4. central groove
5. collateral groove
6. heel
7. bar
8. seat of corn
9. pigmented walls (external layer)
10. water line (inner layer)
11. white line
12. apex of frog
13. sole
14. toe
15. how to measure width
16. quarter
17. how to measure length
