Accessory nerve

Cranial & Spinal part of the accessory nerve & their central connections   . It has 2 parts (Roots) : Cranial root & spin...

Cranial & Spinal part of the accessory nerve & their central connections


 
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It has 2 parts (Roots) : Cranial root & spinal root
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	Cranial part	Spinal part
Cortical connection	Receives corticonuclear fibers from both cerebral hemispheres
Course	It joins the spinal root & leaves the skull through jugular foramen Then the roots separate again, cranial root joins the vagus	Situated in the anterior grey column of the spinal cord  in the upper 5 cervical segments Nerve fibers emerge from the spinal cord & form a nerve trunk that ascends into the skull through the foramen magnum Spinal part joins the cranial part & pas through the jugular foramen Then they separate again
Supply	Supply the muscles of: Soft palate (Except tensor veli palatini) Pharynx (Except stylopharyngeus) Larynx (Except cricothyroid)	Supplies the SCM muscle & trapezius muscle

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Examination of the Accessory nerve
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1) SCM (Left SCM turns had to right & vice versa)

1. Ask the patient to rotate head against resistance
2. Compare the power & muscle bulk in both sides
3. Also compare patient puling head forward against resistance

2) Trapezius

1. Ask the patient to shrug his shoulders & hold them in this position against resistance
2. Compare power on each side
3. Patient should manage any effort to depress shoulders