From the Research
Saturday night palsy is caused by prolonged compression of the radial nerve, typically occurring when a person falls asleep with their arm draped over a hard surface like a chair back or bench, as supported by the most recent study 1. This condition, also known as radial nerve palsy, happens when pressure is applied to the radial nerve as it passes through the spiral groove of the humerus bone in the upper arm. The compression restricts blood flow to the nerve and causes temporary nerve dysfunction.
Key Points
- The name "Saturday night palsy" originated from cases where intoxicated individuals would fall asleep in awkward positions, often on Saturday nights, leading to this condition, although the term may have been mistakenly introduced as a simplification of saturnine palsy, which has a similar clinical presentation 2.
- Symptoms include wrist drop (inability to extend the wrist), weakness in the hand and fingers, and numbness or tingling on the back of the hand.
- Treatment typically involves removing the source of compression, allowing the nerve to heal naturally over weeks to months, and physical therapy exercises may help maintain muscle strength during recovery 3.
- To prevent this condition, avoid sleeping with pressure on your arms and change positions frequently when arms are in potentially compromising positions.
Mechanism and Similar Conditions
The mechanism of Saturday night palsy involves compression of the radial nerve, which can be compared to other conditions such as plumbism (Saturnism) and acute porphyrias, which can manifest similarly with wrist, thumb, and finger drop 1. However, the most recent and highest quality study 1 suggests that the term Saturday night palsy refers to neuropraxia of the radial nerve following prolonged compression against the spiral groove of the humerus, with a unique pattern of weakness and universal recovery by six months.