What Motor Function is Consistent with C4?



  • The nerve root of C4 runs between vertebrae C3 and C4. 

  • Motor function includes:

    • head control

    • neck movement (paraspinal muscles, CN XI, trapezius muscle)

    • ability to breathe possible (diaphragm)

    • mouth control (facial muscles)

    • no upper extremity movement 

What Sensory Function is Consistent with C4?

  • C4 provides sensation across the shoulders.

Assessment of C4 Motor Function


Assess and document motor function using motor scale from 0-5

  • Evaluate ability to shrug shoulders 
  • Evaluate ability to shrug against examiner resistance.

Assessment of C4 Sensory Function

  • Test one side of shoulders, then test same spot on opposite side
  • Always apply the same amount of pressure to each side
  • Ask patient to compare sensation on side A to side B
  • Conceal test from the patient and test light touch and then pain separately. Test bilaterally across the shoulders

Light touch:

use wisp of cotton or tissue

Sharp or temperture touch:

use safety pin or blunt end needle

pain is a better assessment than temperature for this pathway because patients need to be able to articulate that they can distinguish hot or cold; this is unreliable among intubated patients


Expected Outcome

  • use of mouth stick for typing, page turning, switch devices
  • swallowing
  • may have problems maintaining spontaneous ventilation



Barr, M, and Kiernan, J. (1993). The Human Nervous System: An Anatomical Viewpoint. Philadelphia: Lippincott. pp 84-85.

Keppler, J. (1987). Acute spinal cord injury. Critical Care Clinics. July. 3:3. pp. 638-641.

Netter, F. (1989). Atlas of Human Anatomy. New Jersey: Novartis.

Waxman, S. (1996). Correlative Neuroanatomy. 23rd Ed.  Stamford: Lange. pp 46-52, 352-355, 370.

Brenda Morgan
Clinical Nurse Specialist, CCTC
May 11, 2001. Updated: January 15, 2019