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Accessory nerve

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

It has 2 parts (Roots) : Cranial root & spinal root

Cranial part
Spinal part
Cortical connection
Receives corticonuclear fibers from both cerebral hemispheres
  • 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

Examination of the Accessory nerve

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
Accessory nerve Accessory nerve Reviewed by Radiology Madeeasy on August 07, 2010 Rating: 5
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