Wrist drop results when muscles that extend the hand at the wrist become weak. If the wrist can be extended, but not the fingers, the term finger drop is used (Figure 5). These conditions result from loss of function of the radial nerve. One of the most well-known causes is compression of the nerve against the upper arm bone (humerus), often called Saturday night palsy. Fracture of humerus is another cause. For More Information: Wrist drop
