How our hands work?
Our hands are complex feats of biological engineering.
The palm of the hand is made up of five bones called metacarpals. In between are the interossei muscles, and on each side of the palm are bulging muscle groups called the hypothenar (near the little finger) and the thenar (near the thumb). These work to cup the hand and to move the thumb in and out so that it can grip. The bones belonging to the fore and middle fingers don’t move much, but the ones connected to the little and ring fingers and the thumb are much more mobile.
The fingers themselves are made up of bones called phalanges – three for each finger and two for the thumb. They are connected to muscles in the forearm by tendons that run through the wrist. The flexor tendons run up on the underside through a space called the carpal tunnel – they bend the fingers. The extensor tendons come across the top of the wrist – they pull the fingers straight.
All of this movement is controlled by three nerves: the median, radial and ulnar. The median nerve supplies the thumb, the index and middle fingers, half of the ring finger and the palm of the hand. The ulnar feeds the other half of the ring finger and the little finger, and the radial looks after the thumb and the back of the hand.
