At the completion of this chapter, the reader will be able to:
Describe the anatomy and distribution of the vertebral artery.
Describe the four commonly recognized portions of the vertebral artery.
Outline the causes of vertebral artery occlusion or compromise.
Recognize the characteristics of vertebral artery occlusion or insufficiency.
Describe various special tests used to assess the patency of the vertebrobasilar system and their diagnostic value.
Vascular serious adverse events (SAEs) can occur following examination of the cervical spine, mobilization, exercise prescription, or manipulation.1 The most common SAE in the cervical spine is craniocervical artery dissection (57% of cases).1,2 The vertebral artery (VA), a component of the craniocervical artery system, supplies 20% of the blood to the brain (primarily the posterior cranial fossa), with the remaining 80% being supplied by the carotid system. The first studies of the VA were recorded as far back as the 19th century. Since that time, recognition of the importance of the VA has continued to grow, and it is now discussed in more detail than any other artery by physical therapists. Neck pain, orofacial symptoms, and/or headache, all common complaints from patients who seek physical therapy, are often the first (non-ischemia) symptoms of an underlying craniocervical artery dissection.1,3 For this reason, the VA is afforded its own chapter. To fully comprehend its significance, a review of its anatomy and function is in order.
The vertebrobasilar artery (VBA) system consists of three key vessels: two VAs and one basilar artery. The basilar artery is formed by the two VAs joining (Fig. 24-1).
The vertebral artery and its relationship to the cranial arteries. (Reproduced with permission from Morton DA, Foreman KB, Albertine KH. The Big Picture: Gross Anatomy. 2nd ed. New York, NY: McGraw Hill; 2019.)
Along its course, the artery can be viewed as having four portions: proximal, transverse, suboccipital, and intracranial.
This portion runs from the origin of the artery to its point of entry to the cervical spine. The VA usually originates from the posterior surface of the subclavian artery, but it can also originate from the aortic arch and common carotid artery.
The VA runs vertically, slightly medial, and posteriorly lateral to the longus colli and medial to the anterior scalene muscles to reach the transverse foramen of the lower cervical spine, although its exact direction is dependent on its exact point of origin. The artery’s anomalous origin in this region has been suggested as a potential factor increasing the chance of blood flow compromise due to compression by the longus colli or scalene muscles.