Which spinal nerve root is primarily associated with shoulder movement?

The spinal nerve root primarily associated with shoulder movement is C5. This nerve root plays a crucial role in the motor functions of the shoulder, particularly in innervating the deltoid and supraspinatus muscles, which are essential for shoulder abduction. The C5 nerve root also contributes to shoulder flexion, extension, and external rotation due to its involvement with various muscles like the biceps brachii and infraspinatus.

In addition to its motor functions, C5 is responsible for providing sensory innervation to the skin over the shoulder and lateral arm, which helps integrate motor control with sensory feedback during movement. This makes C5 particularly vital for coordinating complex movements that involve the shoulder, illustrating its importance in both the anatomy and functional physiology of upper limb mobility.