The Saturday Night Palsy or Why You Should Be Nice To Your Nerves
You may be familiar with the picture, either personally or from a story somebody told you. A young man goes out for the evening, all dressed up and smelling of aftershave. He meets his mates in the pub and has a few beers, starting off the process of intoxication which continues most of the night. After the pub there is the nightclub and more drinking until it's time to roll out and round to the kebab house to have a snack. After a bit more hanging about he goes home or to one of his mates' houses to watch television, chat and perhaps drink a little more.
There is nothing exceptional in the story so far and our young man will not be shocked at all by the fact that he is very likely to feel hung over tomorrow. The surprise is due to what happens when he is watching the TV and he falls asleep. However, he has placed his arm over the back or the arm of the chair he is half lying in and that's the position in which he stays for some hours as he sleeps soundly. When he awakes he finds himself still in the chair with his arm over the back or the side, however he can't move his arm properly like he has slept on it and got a dead arm.
The real problem here was not so much the odd posture adopted in the chair when he fell asleep but the fact that he was drunk. If he had been sober the discomfort in the arm would have either woken him or made him move the arm at some point to a different position. The armpit tissues have had to endure a significant weight on them for a long time and the result is an arm which is almost paralysed. Our young man has tried to shake it back to life but it has not responded to this.
Our nerves are a reactive tissue, that's what they are designed for. But they won't take too much pressure for too long a time without reacting in a negative manner. One of the things nerves don't like is direct pressure. If subjected to undue pressure for too long, also referred to at times as honeymooners' palsy which is due to the tendency for one person to rest their head on the arm of the other whilst sleeping, the blood supply to the nerve becomes interrupted and the nerve develops a neurapraxia.
Nerve damage is classified into three categories: axonotmesis, neurotmesis and neurapraxia. Neurapraxia is the mildest variety of nerve trauma and there is internal biochemical damage to the nerve but no break in the internal axon or the nerve itself. The nerve being intact, it does not need to regenerate but recover. Nerve impulse conduction is disrupted by the area of nerve trauma and gives paralysis of the muscle with some difference in feeling. Compression may cause avascular damage to the nerve, resulting in inflammatory changes.
While the arm will recover from the nerve insult which it has suffered, sometimes quite quickly, an average recovery time to good function is between six and eight. The major functional disruption is the loss of the ability to move the arm and the ability to feel the arm and control the circulation and sweating to it are either less affected or not affected. Examination by a doctor is useful to exclude more severe injury to the nerve and to caution the patient in how to look after their arm until it recovers, particularly if there is feeling loss.