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