There is no such thing as a doctor that specializes in leg injuries. If you have a leg injury, you should go to your local emergency department for treatment.
In England we call it 'cocking' their leg.
A tortoise leg
Hind leg, flank, back leg, or rear leg.
Lotion
you call it a leg that has been hurt not severely but maybe damaged somehow
pleopod
lame
Quadraped.
a limb
Handicapped.
Muscles