The Mind sends messages with the nerves telling the muscles of the forearm and hand how and when to maneuver. Boutonniere Deformity: The MCP (metacarpophalangeal) joints along with the DIP (distal interphalangeal) joints are affected.  The main damage should be to flexion of the proximal interphalangeal joints as a result of https://www.theorthopaedicandpainpractice.com/what-are-the-different-bones-found-in-my-hand/