Knuckles behind the hand permit the fingers to maneuver forward and backward. They are essential in battle sporting activities like wrestling and boxing. The ulnar nerve enters the hand beneath the superficial Section of the flexor retinaculum (in Guyon’s canal) after which it divides to the deep and superficial branches. https://www.theorthopaedicandpainpractice.com/what-are-the-different-bones-found-in-my-hand/