The main nerves in the arm, originating from the brachial plexus, are the musculocutaneous, axillary, radial, median, and ulnar nerves. These nerves control various functions in the arm, hand, and shoulder.
Understanding Arm Nerves
The nerves in your arm are essential for movement and sensation. They originate from a complex network called the brachial plexus. The final outputs of this plexus are the five primary nerves that innervate the shoulder and arm.
Primary Nerves of the Arm
These five primary nerves are commonly referred to as the "branches" of the brachial plexus. Below is a description of each nerve and its functions:
| Nerve | Function |
|---|---|
| Musculocutaneous | Controls muscles in the front of the upper arm (like the biceps) and provides sensation to the lateral forearm. |
| Axillary | Innervates the deltoid muscle (shoulder) and the teres minor, and provides sensation over the outer shoulder. |
| Radial | Controls muscles on the back of the arm and forearm, responsible for extending the wrist and fingers, and provides sensation to the back of the hand. |
| Median | Innervates the muscles of the forearm and hand involved in pronation and wrist and finger flexion, and provides sensation to part of the palm and some fingers. |
| Ulnar | Controls muscles of the forearm and hand involved in wrist and finger flexion, as well as fine motor control of the hand, and provides sensation to the little finger and part of the ring finger. |
These nerves work together to ensure that the arm functions correctly, allowing for a wide range of movements and tactile sensations.
Practical Insights
- Understanding which nerve controls which muscles and areas of sensation can help in diagnosing nerve injuries.
- Damage to these nerves can result in weakness, pain, or numbness in specific parts of the arm and hand.
