extremity vs trigger finger

extremity

noun
  • A hand or foot. 

  • The most extreme or furthest point of something. 

  • A limb (“major appendage of a human or animal such as an arm, leg, or wing”). 

  • An extreme measure. 

trigger finger

noun
  • the forefinger 

  • a finger used in pulling the trigger of a firearm 

  • difficulty encountered in finger flexion or extension caused by the narrowing of the sheath that surrounds that finger's tendon 

How often have the words extremity and trigger finger occurred in a corpus of books? (source: Google Ngram Viewer )