Spinal Accessory Nerve (CN XI) | Anatomy & Functions

The video tutorial discusses the spinal accessory nerve, also known as cranial nerve 11, which is a motor nerve innervating the trapezius and sternocleidomastoid muscles. It challenges the traditional definition of cranial nerves by explaining that the spinal accessory nerve originates from the spinal cord, not the brain. The nerve ascends through the foramen magnum and exits the cranium via the jugular foramen. The tutorial also covers the clinical implications of damage to this nerve, such as ipsilateral issues in muscle function and atrophy.

What is the primary function of the spinal accessory nerve?

Which two muscles are innervated by the spinal accessory nerve?

How does the spinal accessory nerve differ from other cranial nerves in terms of its origin?

Describe the pathway of the spinal accessory nerve as it exits the cranium.

What clinical manifestations might occur if the spinal accessory nerve is lesioned?

Explain the significance of the jugular foramen in relation to the spinal accessory nerve.

What is the relationship between the sternocleidomastoid muscle and the spinal accessory nerve?