IV.B.5 Head: CN XI & CN XII Page 1 of 2

Objectives:

3.6.1 Identify the foramen through which the spinal accessory and hypoglossal cranial nerves exit the cranial cavity and include the components of each cranial nerve.

3.6.2 Describe the origin and path of the spinal accessory and hypoglossal nerves.

3.6.3 Predict the functional deficits, which would result from damage to the spinal accessory nerve (CN XI) and Hypoglossal nerve (CN XII).

Assigned Readings:

Moore's COA: Pages 842-844, 931, 951-953, 1006-1011, 1014, 1044-1045, 1062-1069, 1083-1085. See the blue boxes on page 1091 for clinical correlations. See the yellow boxes on pages 1083, 1085 for "The Bottom Line."

Neuroanatomy: Pages 62-62, 534-535.

	Step 1: Begin with a sagittal brain section.
	Step 2: Add the accessory nerve CN XI (also known as the spinal accessory nerve).

The accessory nerve is unusual because it arises from the upper 5 segments of the spinal cord.

It enters the cranium via the foramen magnum, crosses the posterior fossa and then exits via the jugular foramen.

The accessory nerve then innervates the sternocleidomastoid muscle and the trapezius muscle. (GSE)

Step 3: Using the Rotate tool, rotate the cadaver to appreciate the path of this unusual cranial nerve.