Final answer:
The sternocleidomastoid and trapezius muscles are the primary muscles encountered in C5-6 surgical approaches, innervated by the spinal accessory nerve, and are key in head and neck movements.
Step-by-step explanation:
The muscle most often encountered during surgical approaches to the C5-6 vertebrae is the sternocleidomastoid. This muscle, along with the trapezius, plays a significant role in the movement of the head and neck, as well as elevating the scapula and clavicle. These muscles are innervated by the spinal accessory nerve, also known as the accessory nerve, which is tested by having patients flex and extend the neck or shrug their shoulders against resistance to assess the strength and function of these muscles.
When performing surgery in the C5-6 area, the identification and careful manipulation of the sternocleidomastoid and trapezius are crucial due to their location and the potential impact on neck mobility and strength.
The muscle most often encountered during surgical approaches to C5-6 is the trapezius muscle. The trapezius is innervated by the accessory nerve and plays a significant role in changing the position of the head. It receives motor input from the spinal cord and contributes to elevating the scapula and clavicle.