Atypical Course of Vertebral Artery Outside the Cervical Spine: Case Report and Review of the Literature

The vertebral arteries are branches of the subclavian arteries supply blood to the posterior part of the encephalon, forming vertebrobasilar circulation. Disorders of vertebrobasilar circulation have significant clinical implications. Symptoms of these disorders include dizziness, vomiting, collapse, vision and cerebellar disorders. The vertebral artery usually ascends in the transverse foramina of the cervical vertebrae to reach the posterior cranial cavity by entering the magnum foramen. Although most often the vertebral artery enters the C6 transverse process, anatomic variation may occur. In this case, a 16-year-old male patient with casuistic anatomic variant of vertebral artery course is described. In this case report, left vertebral artery ascended outside the transverse foramina of cervical vertebrae C6-C3 and entered transverse foramen of axis. The patient suffered from collapse and dizziness during neck and head movements as a result of arterial folding. After rehabilitation and posture and proper movement learning, the frequency of symptoms subsided. Variability of the vertebral arteries may have clinical implications, and knowledge of its topography is important for mechanism of vertebrobasilar circulatory disorder understanding and for surgical approach to the cervical spine and neck anatomic structures.