Basic Anatomy of the Median, Radial and Ulna Nerves

The nerves of the neck and arm are designed to cope with the full movement of the arm and neck and you are not normally aware of nerve movement as you move your arms. 
The nerves are like a series of thin cables that pass from the neck to the tips of the fingers.

Median Nerve

As demonstrated in this picture the Median nerve runs from the neck down pat the front of the shoulder joint, down the front of the arm, past the elbow to the middle three fingers. The exact fingers it goes to varies from person to person. 

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Radial Nerve

As illustrated in this picture; the Radial nerve also passes down the arm but as it goes it winds around the upper arm and passes over the outer front of the elbow and then down to the forearm and thumb. 

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The Radial Nerve as it passes the elbow

Another view of the Radial Nerve as it passes the elbow

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Ulna Nerve

As illustrated in this picture the Ulna nerve passes from the neck down the inside of the arm and pass the inside back of the elbow (where it sits in a groove at the back of the elbow it is called the 'funny bone'; when it is knocked causing a tingling feeling). The Ulna nerve continues down the arm to the fifth finger. 

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The Ulna Nerve as it passes the elbow

Another view of the ulna nerve as it passes the elbow

The nerves are made up of thousands of tiny 'copper wires' called axons. The axons are covered by layers of protective 'insulation'. The nerves have a nerve supply; there are pressure and nociceptive (damage) receptors in the protective insulation.