Muscle Weakness
The fourth and fifth cervical nerves supply motor function to the muscles of the shoulder and arm. When either of these nerves is compromised, muscle weakness can result. Specifically, the C4 nerve enervates the levator scapulae, trapezius and rhomboid muscles. Damage to the C4 nerve may result in difficulty in elevating the shoulders. The C5 nerve supplies the deltoid, supraspinatus, infraspinatus and biceps muscles. Damage to the C5 nerve can affect the ability to raise the arm or bend it at the elbow.
Read more: http://www.livestrong.com/article/139943-c4-c5-nerve-damage-symptoms/#ixzz2nizo16IS
