Claw hand deformity from ulnar neuropathy

Image of a patient with a partial ulnar nerve paralysis who is asked to extend the digits. Hyperextension of the MCP joints of the ring and small fingers occurs with the loss of intrinsic ulnar-innervated MCP flexors. The index and middle fingers have median innervated intrinsics (lumbricals) that allow the extrinsics to extend the IP joints.