Saturday night palsy

Etymology
Introduced mistakenly as a simplification of, a complication of lead poisoning which has a similar presentation.

Folk etymology associates it with carousing and intoxication on Saturday nights, which causes the individual to fall asleep in unnatural positions, such as on a chair or bed with one arm hanging over the edge.

Noun

 * 1)  Paralysis due to radial nerve compression in the arm, resulting from direct pressure against a firm object.