What it is a part of

ногђ foot; leg
пїтка лљвой ногќg the heel of the left foot
NB Note that neither ступнќg "foot" nor подћшвыg "foot" can be substituted for ногќg here. Note also that in some contexts, mostly in formal style, the word пїтки (plural) can combine with the plural form нћгg:
При рождљнии оказђлось, что у ребёнка деформќрованы пїтки нћг. When the child was born it turned out that its heels were deformed.