3. After a night out on the town, this patient is concerned that something is wrong, and it’s not the splitting headache: He is unable to extend his right wrist, thumb, or fingers in the pronated position. Furthermore, the radial and dorsal skin is numb. During the history, he reports that he fell asleep sitting upright with his arm over the back of a chair.
Diagnosis: Radial neuropathy, or Saturday night palsy, is typically produced by direct, prolonged pressure on the radial nerve. The nerve is especially susceptible as it spirals around the midportion of the humerus, in this case by allowing the hard edge of a chair back to compress it all night long. Although alcohol and drugs are usually implicated, radial palsy can also result from fracturing the humerus, leaning on crutches, or from long-term constriction of the wrist (tight watch or bracelet).
For more information, see “9.19 Radial Neuropathy (Saturday Night Palsy).”