Ulnar Claw Hand (Claw Hand): this is due to a lesion in the ulnar nerve. The MCP joints are hyperextended for the ring and little fingers as a result of loss of the 3rd and fourth lumbrical muscles as a result of a lesion of your deep department from the ulnar https://www.theorthopaedicandpainpractice.com/what-are-the-different-bones-found-in-my-hand/