Semantics

leg
Ћн бІстро сџнул нћги в брєки и побежђл. He quickly shoved his legs into his pants and set off at a run.
foot
Пћсле лљта нћги Пљти не влезђли в стђрые тџфли. At the beginning of fall, Petya's feet no longer fit into his old shoes.
Кћнь нетерпелќво переступђл ногђми. The horse impatiently shuffled its feet.
Russian differs from English in that the word ногђ may mean either "leg," (i.e. either of the two lower limbs of a biped, including a human being, or any of the paired limbs of animals) or "foot" (i.e. the part of the leg below the ankle joint). This entry is concerned with both of these uses. Common sense will dictate which of the expressions in this entry can or cannot be used to refer to animals or humans.

For the distinction between the word ступнї1 and its synonym ногђ, see Lexical Relationships: Synonyms.