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Special Test

Vertebral Artery Test

Vertebral Artery Test or De Klyn Test is used in the assessment of vertebral, basilar, or carotid artery stenosis or compression.

How do you perform the Vertebral Artery Test?

This test requires certain preliminary findings as it is not entirely without risk. Parameters requiring prior assessment include blood pressure, arm pulse, and pulses in the common carotid and subclavian arteries with auscultation to detect any murmurs or bruits.

This test should not be performed if any of these prior examinations produces significantly abnormal findings. In the absence of any significant abnormalities, the seated patient is asked to maximally rotate his or her head to one side while extending the neck.

See Also: Allen Test
Vertebral Artery Test - seated position
a: Starting position. b: Rotation of the head and extension of the cervical spine.

The test can also be performed with the patient supine, in which case the patient’s head projects over the edge of the examining table and rests in the examiner’s hands. Then with the head hanging down (in the De Klyn position), the head is maximally rotated and the neck extended. The head should remain or be held in maximum rotation and extension for about 20 to 30 seconds. The patient is then requested to count out loud.

See Also: 	 Adson Test
Vertebral Artery Test - supine position
Vertebral Artery Test – Supine position

What does a positive Vertebral Artery Test?

Abnormal auscultatory findings in the common carotid artery, vertigo, visual symptoms, nausea, fatigue, or nystagmus occurring during this maximum rotation and extension indicate stenosis of the vertebral artery or common carotid artery. The test is especially important in candidates for treatment (such as traction or manipulative therapy) of cervical spine symptoms associated with vertigo. The vertebral artery provocation test aids in the differential diagnosis because nausea, vertigo, and nystagmus initially increase but then rapidly decrease in intensity when a vertebral blockade is present. In the presence of vertebral artery insufficiency, the intensity of nausea and vertigo symptoms will rapidly increase within a few seconds without abating

See Also: Thoracic Outlet Syndrome

Vertebral Artery

The vertebrobasilar artery (VBA) system consists of three key vessels: two Vertebral Arteries and one basilar artery. The basilar artery is formed by the two Vertebral Arteries joining each other at the midline. Along its course, the artery can be viewed as having four portions: proximal, transverse, suboccipital, and intracranial.

The VA is most vulnerable to compression and stretching at the level of C1–2 because of the amount of cervical rotation that can occur at the atlantoaxial joint.

The VA that is most vulnerable to a stretch injury during neck rotation is usually the one that is contralateral to the side of the rotation. For example, the left VA is more vulnerable with rotation to the right. During right rotation, the left transverse foramen of C1 moves anteriorly and slightly to the right. This movement imparts a marked stretch on the left VA, and it increases the acuteness of the angle formed between its ascending and posteromedial courses.

The most common mechanism for a nonpenetrating trauma injury to the VA is hyperextension of the neck, with or without rotation, or cervical side flexion. These motions can result in stretching and tearing of the intima and media, especially at the points where the artery is tethered to a bone.

The clinician should use a combination of the patient,s description of the symptoms and medical history, and those considerations are:

  1. Inherent redundancy of blood supply – collateral circulation
  2. Morphology of the vertebral artery at the atlantoaxial level
  3. Biomechanics of upper cervical spine – concurrent contralateral side bending with cervical rotation
  4. The nonvascular causes of dizziness (cervicogenic dizziness and benign paroxysmal positional vertigo)
  5. The amount of cervical rotation to be used
  6. Medical history (transient ischemic attack, cerebrovascular accident, cardiac risk factors, cervical spondylosis)
  7. Psychometric properties of vertebral artery testing (0% sensitivity)
  8. Force to be applied
  9. Potential risk of injury with manipulation (thrust, rotational techniques vs nonthrust, nonrotational techniques).
Vertebral Artery anatomy
Vertebral Artery anatomy


  1. Taylor AJ, Kerry R. The ‘vertebral artery test’. Man Ther. 2005 Nov;10(4):297; author reply 298. doi: 10.1016/j.math.2005.02.005. PMID: 15908259.
  2. Feudale F, Liebelt E: Recognizing vertebral artery dissection in children: a case report. Pediatr Emerg Care 16:184–188, 2000.
  3. Fast A, Zincola DF, Marin EL: Vertebral artery damage complicating cervical manipulation. Spine 12:840, 1987.
  4. Ouchi H, Ohara I: Extracranial abnormalities of the vertebral artery detected by selective arteriography. J Cardio Surg 18:250–261, 1973.
  5. Vidal PG: Vertebral artery testing as a clinical screen for vertebrobasilar insufficiency: Is there any diagnostic value? Orthop Pract 16:7–12, 2004.
  6. Clinical Tests for the Musculoskeletal System 3rd Edition.
  7. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
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