The nerves that control all of your hand’s muscles start at the shoulder: the radial nerve, median nerve, and ulnar nerve. These nerves are integral to all the things your hands do and to how your hands feel. They carry signals from the brain to the muscles that move your arms, hands, fingers and thumbs, and then carry signals from those body parts back to the brain about the sensations you feel (touching a texture, feeling pain and temperature).
The radial nerve wraps around the end of the radius bone towards the back of the hand, from the thumb side of your forearm. It allows for you to feel sensations in the back of your hand, from the thumb to the third finger. The radial nerve also gives sensation to the back of the thumb, to the main knuckle and backs of the ring and middle fingers.
The median nerve travels through the wrist in a vessel called your carpal tunnel. You’ve definitely heard of the carpal tunnel, as many people are prone to experiencing carpal tunnel syndrome. The median nerve is responsible for many of your fingers’ abilities to feel sensations (thumb, index finger, long finger, half of the ring finger), and also has a nerve branch that controls the thumb’s thenar muscles. These muscles are the ones that specifically help your thumbs be opposable, permitting your fingertips and the pads of your thumbs to touch if they are on the same hand.
Meanwhile, the ulnar nerve proceeds through a different tunnel called the Guyon’s canal. The Guyon’s canal is formed by two carpal bones (pisiform and hamate) and a ligament that makes them attach. The ulnar nerve, traveling through the canal, supplies the little/pinky finger and the other half of the ring finger with sense capability. Ulnar branches also help muscles in the palm and thumb to feel as well.
Your hands are multifunctional and help you with pretty much everything in your daily life, thus the nerves that control them can be subject to many issues. Movements like constant bending, twisting and straightening of the wrists and fingers can lead to these nerves suffering irritation and pressuring their tunnels. Symptoms may include pain, numbness/lack of sensation, and your fingers/hands/thumbs becoming weak.