Which spinal nerves are involved in the innervation of the radial nerve?

The radial nerve is primarily derived from the posterior cord of the brachial plexus, which involves spinal nerves from C5 to T1. This extensive range is essential because it encompasses the upper limb's sensory and motor functions facilitated by the radial nerve. C5 contributes to the shoulder region, while C6, C7, C8, and T1 provide innervation for various muscles in the upper arm, forearm, and parts of the hand.

Understanding this range is crucial for recognizing how upper limb movements and sensations are affected by injuries to these spinal nerves. Therefore, the correct answer reflects the necessary spinal nerves that contribute to the radial nerve and its functions in the upper limb.