Syntax

Syntactic actants

Actant 1: whose finger it is
(a) Genitive
(b) Possessive
Длинные пальцы Сергея быстро двигались по клавишам. Sergey's long fingers quickly moved across the keyboard.
От стирки её пальцы распухли. Her fingers were swollen from doing the washing.
NB When the word палец functions as a subject and does not have a descriptive modifier, the construction палец у + Genitive is often preferred to (a) and (b), above:
От стирки у неё распухли пальцы. Her fingers were swollen from doing the washing.

Restrictive modifiers

(a) Noun phrase: Adj + Genitive of рука
(b) Prepositional phrase: на (+ Adj) + Prepositional of рука
NB Note that (b) is more common than (a).
пальцы левой/правой руки the fingers of the left/right hand
пальцы на левой/правой руке the fingers on the left/right hand
У неё распух большой палец левой руки (or на левой руке). The thumb of/on her left hand had swelled up.