…your fingers prune up after long baths. 

Ever laughed about how wrinkly your fingertips get after you take a long bath or shower? Well, your nervous system makes this happen! It does so by compressing the blood vessels underneath your skin on the fingertips. But why, you ask? Scientists have discovered that this might be due to evolution. The pruned-up skin on the fingertips might have helped our ancestors from previous stages of evolution to grip wet objects better. This would have been useful for them when trying to find food in wet areas like streams. A recent experiment conducted in the UK demonstrated this improvement in grip. Further research is being conducted on this evolutionary topic. 

…you feel like pins and needles are poking you. 

When you sit or sleep on one part of your body for a long time, the paths of nerves are squeezed and their messages are not sent properly. So, the brain cannot properly talk to this body part. Moreover, your arteries also get squeezed by the pressure. Thus, nutrients do not reach the cells of your body properly, and the nerve cells further act differently. This can lead to problems in transmitting your body’s sense-based data. As a result of these two issues, the brain receives unusual information from these body parts. This leads to the feeling of a body part ‘falling asleep’. This is important because it notifies you of the problem so you can stop applying pressure. Over a long duration, such pressure can lead to severe nerve damage. However, the tingling feeling does not stop the moment you stop putting pressure on the body part. It takes some time for your nerve cells to start sending the correct messages to your brain. Also, different types of nerve cells take different amounts of time to go back to normal. This results in a more intense ‘pins and needles’ feeling for a while, even after you’ve adjusted your arm or leg. 

…it hurts so much when you hit your funny bone. 

Have you ever been surprised by the strong, tingly, and painful feeling you get on hitting your funny bone, the little bump right next to your elbow joint? The culprit is your ulnar nerve. This nerve starts at your spine, runs all along your arm, and ends at your pinky and ring fingers. Muscles and bones cushion it, but near the elbow, this nerve has to go behind the medial epicondyle, a protruding part of the upper arm bone (humerus). At this part, the ulnar nerve is right in between the bone and your skin. When you hit your funny bone at a particular angle, this nerve is squeezed against the medial epicondyle. This causes the tingly pain which you then feel in your entire forearm, as the nerve itself extends to your fingers.