If you are a dog owner, you should know about the basic anatomy of the paw so you can describe to your vet or animal care practitioner about the location of pain or injuries.
Photo courtesy of Wikipedia
A = the nails
B = digital pads
C = main metacarpal pad
D = dew claw
E = carpal pad
DoggyMom.com 
Thank you, it will help next time one of them has an injured paw and I attempt to describe the problem.