What Are the Major Nerves of the Hand?

The median nerve begins at the armpit and extends all the way to the hand. This nerve is formed at the brachial plexus, a group of nerves that branch out from the cervical spine in the neck. From the armpit, the median nerve travels down the length of the inner arm between the biceps and triceps tendons beside the brachial artery. The median nerve serves no function in the upper arm, but it’s responsible for supplying nerves to nearly all the muscles of the forearm.

Past the elbow, the median nerve travels down the forearm with the ulnar nerve. It connects to the flexor and pronator muscles of the forearm. The median nerve passes through the carpal tunnel in the wrist to enter the hand. In the hand, the median nerve serves the muscles at the base of the thumb, known as the thenar eminence, and the lumbrical muscles that move the index and middle fingers. The median nerve controls the flexion of particular muscles in the forearm and hand. It allows:

• The wrist to bend.
• The first two fingers to bend.
• The thumb to bend.
• The forearm to rotate such that the hand can face down.

The median nerve also supplies sensation to the forearm and hand. It allows you to feel heat, cold, touch, and pain in the forearm, the thumb side of the palm, the top of the index and middle fingers, and the palm side of the thumb, index finger, middle finger, and some of the ring finger.

The median nerve is one of the best-known nerves in the hand because it’s associated with carpal tunnel syndrome. This disorder occurs when the tissue inside the carpal tunnel compresses the median nerve, resulting in finger pain, wrist pain, and numbness.

If the anterior interosseous branch of the median nerve becomes damaged, it can result in anterior interosseous nerve syndrome. This condition causes wrist pain as well as weakness and paralysis in the thumb and index finger. This can make it difficult to grasp items with the typical pinching motion.

You may also experience numbness or paralysis in the fingers as the result of pronator teres syndrome. This occurs when the pronator teres muscle at the elbow pinches the median nerve. This condition typically causes a dull pain in the forearm as well.

Like the median nerve, the radial nerve is formed at the brachial plexus and travels through the armpit. The radial nerve wraps around the back of the humerus bone in the upper arm, supplying the triceps muscles with nerves that allow you to bend or straighten your elbow. The radial nerve passes through the radial tunnel in the elbow as it travels down the outside of the elbow and forearm.

The radial nerve supplies the muscles that straighten your wrist and fingers and control the positioning of your hand. The deep branch of the radial nerve helps control the rotation of your forearm. The radial nerve supplies sensation to the back of the little finger, part of the ring finger, and the thumb side of the back of the hand.

If the radial nerve gets compressed at the radial tunnel, it can cause radial tunnel syndrome. This condition causes pain and tenderness along the outside of the elbow and down the forearm. It may weaken your forearm and wrist, making it difficult to flex your wrist, lift your hand, or rotate your forearm.

Damage to the radial nerve can cause radial nerve palsy, a condition that causes weakness and numbness in the forearm, wrist, hand, and fingers. If the radial nerve is compressed during forearm rotation, you may suffer from a condition known as Wartenberg’s syndrome or cheiralgia paresthetica. This condition causes pain, tingling, and numbness in the forearm, wrist, and hand.

The ulnar nerve begins at the brachial plexus in the armpit and connects to the C8 cervical vertebrae and T1 thoracic vertebrae. It runs down the front of the upper arm, through the cubital tunnel, and down the inside of the forearm alongside the median nerve and ulna. The ulnar nerve then enters the palm near the pinky finger through the ulnar tunnel. The ulnar nerve:

• Controls forearm movement at the front.
• Provides sensation to the pinky and ring fingers.
• Provides sensation to the palm of the hand.

When you hit your elbow, or “funny bone,” and experience a sudden sensation of tingling, burning, and numbness, you’ve briefly pinched the ulnar nerve. Pinching or compressing the ulnar nerve for prolonged periods of time can result in more serious complications.

Pressure on the ulnar nerve can cause ulnar nerve entrapment. This can lead to cubital tunnel syndrome, which may cause tingling and numbness in your hand and fingers. It may also make it difficult to move your fingers. Pressure on the ulnar nerve can also result in ulnar tunnel syndrome, which causes symptoms similar to carpal tunnel syndrome.

You should never ignore signs of nerve trouble. If you’re having difficulties moving your forearms, wrists, hands, or fingers, or if you have pain, tingling, or numbness in these areas, you should see a specialist as soon as possible. Your doctor may recommend a variety of treatments, such as a splint, physical therapy, nonsteroidal anti-inflammatory drugs, or surgery for a pinched or compressed nerve. Our experts at The Hand and Wrist Institute in the Dallas, Texas, area can diagnose and treat conditions affecting any of the major nerves in the hand. Make your appointment now.