Lumbrical mm

The lumbricals are small intrinsic hand muscles that originate from the tendons of the flexor digitorum profundus and insert into the extensor tendons of the digits.  They flex the MCP joints, and extend the IP joints.  The two lateral muscles (I and II) are innervated by the median n.  The two medial muscles (III and IV) are innervated by the ulnar n.