There are a total of 29 bones in the hand/wrist.
- 14 phalanges
- 5 metacarpals
- 8 carpals: The carpals form a tunnel that the a nerve travels through (median nerve). This nerve sometimes becomes trapped or compressed resulting in "carpal tunnel syndrome"
- (2) the radius and the ulna help form the wrist joint.
There are bands of ligaments that help hold the numerous bones of the hand together. These can sometimes become injured (sprained) due to falls or impacts. A ligament that needs mentioned is the Transverse Ligament. This ligament covers the carpal bones (bones of the wrist) in addition it covers the median nerve. In some cases, the median nerve becomes irritated and gets compressed by the transverse ligament resulting in "carpal tunnel syndrome".
There are 5 major nerves that run down the shoulder to the hand. We will mention 3 of the 5 for they are most common in elbow/forearm and hand injuries.
The median nerve runs from the neck down to the palm side of the hand (thumb, first finger and 1/2 of the middle finger). This nerve is involved in carpal tunnel syndrome. These nerves innervate the forearm flexors.
The ulnar nerve runs from the neck down to the palm of the hand (pinky, ring finger and 1/2 of the middle finger). This nerve is also known as the "funny bone". As it travels down the arm, it curves around the inside of the elbow; at that point it is close to the surface of the skin and isn't covered by muscle so can be accidentally bumped or hit causing numbness and tingling down the arm and into the hand. This nerve innervated muscles on the pinky side of the hand/forearm.
The radial nerve runs from the neck down the back side of the forearm to the hand (thumb, first finger, middle finger and 1/2 of the ring finger). This nerve innervates the muscles that extend the fingers and the wrist.