The laughing bone is scientifically known as the ulnar nerve (the primary nerve in the arm), as it travels from the spine through the neck to slip down the upper arm after a groove in the humerus, extending from the shoulder to the elbow.
The ulnar nerve is responsible for transmitting information from some fingertips to the brain and back again. In particular, it allows a person to register the sensations in their pinky and ring fingers, as well as control some movement in the hand.
For most of the nerve’s journey, it is stored by bone, muscle, and fat. When the nerve is woven past the elbow, it passes through a small channel called the cubital tunnel. As it crosses this space, it passes through a bony hook at the elbow where the ulna meets the humerus.
Why is this area so sensitive?
“When a nerve passes through a bony tunnel at your elbow, it exposes,” said Dr. Dominic King, M.D., a sports medicine physician at the Cleveland Clinic Orthopedic and Rheumatology Institute. Opposite the bony edge, the ulnar nerve suffers from what is called ulnar nerve entrapment, or the rapid onset of sharp, electric shock-like pain that extends down the arm and into the hand, and strange numbness down the limb,” according to rt.
There is a question that says:If it is a nerve, then why is it called the laughing bone?
The most plausible explanation lies in the anatomy of the arm. Remember: the large bone that extends from the shoulder to the elbow is called the humerus.
The second explanation lacks humour, as it is based on the ‘funny’ sensation a person feels when a nerve is hit, suggesting that it was described by someone who tolerates pain to a very high degree. Other mammals also have a similar make-up, but they rarely encounter the same problem. These animals are protected by more muscle mass around the sensitive nerve that builds up around the different ways they move. And padding adds a level of protection against this not-so-funny experience.