The Medical Term For The Numbness You Experience When A Limb “Falls Asleep” Is?
It happens to the best of us: you spend too long sitting in the same position, perhaps with a foot tucked under your leg at your desk, or asleep in bed with your arm bent at an odd angle beneath your head, and suddenly it feels like the limb in question is being pricked thousands of times. This “pins and needles” effect, as it is colloquially called, or your limb “falling asleep”, is clinically referred to as “paresthesia”.
The word, derived from the Greek roots para (“beside”, i.e. abnormal) and aisthesia (“sensation”), is a broad term used to describe any abnormal sensation in the skin. The most common example is the aforementioned “pins and needles” tingling we experience when we pinch a nerve by sitting in a way that puts pressure on our legs or sleeping/laying in a way that puts pressure on our arms, but is totally harmless. Once your body sends the signal that things are amiss and you rearrange your body to relieve pressure on the nerve, everything returns to normal shortly thereafter (once we’ve endured, of course, the “pins and needles” effect).
Less common forms of paresthesia include a burning sensation on a person’s skin and, in extreme and unpleasant cases, “formication”, the sensation that insects are crawling under your skin. For most people, however, the experience is limited to the “pins and needles” variety, and it is very transient.
If, however, you find yourself experiencing any form of paresthesia without a clear physical trigger (such as sitting cross legged for a long time or sleeping with your arm under your head), it would be wise to seek medical attention. Common causes of paresthesia not triggered by physical pressure on the nerves include disorders which cause poor circulation (such as peripheral vascular disease), vitamin deficiency and malnutrition, various forms of poisoning (such as mercury and lidocaine poisoning), hyper and hypoglycemia, and hypothyroidism, among other medical problems.