Which spinal nerves innervate the posterior scalene muscle?

The posterior scalene muscle is primarily innervated by the spinal nerves originating from the cervical plexus, particularly involving the lower cervical nerves. C6 to C8 contribute nerve fibers that provide motor innervation to this muscle.

The posterior scalene is situated in the lateral neck and plays a role in elevating the second rib, as well as aiding in flexion and rotation of the neck. Understanding the innervation is crucial, especially when considering the anatomical relationships in the neck and how they affect both movement and potential neuromuscular issues.

The other groups of spinal nerves listed do not provide the primary innervation to the posterior scalene. While C3-C5 includes some nerves that assist in neck functions, the specific focus on C6-C8 highlights the more direct connection to the posterior scalene. Similarly, C1-C3 are involved in more superior neck functions, and C2-C6 would encompass nerves that include those innervating other muscles but are not specifically targeted towards the posterior scalene.