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