Ulnar Claw Hand (Claw Hand): this is due to a lesion with the ulnar nerve. The MCP joints are hyperextended for the ring and tiny fingers due to lack of the 3rd and fourth lumbrical muscles due to a lesion of your deep branch of the ulnar nerve. Each individual phalanx https://www.theorthopaedicandpainpractice.com/what-are-the-different-bones-found-in-my-hand/