Craniocervical Junction Syndrome: Anatomy of the Craniocervical and Atlantoaxial Junctions and the Effect of Misalignment on Cerebrospinal Fluid Flow

Abstract

The craniocervical junction (CCJ) is comprised of the inferior surface of the skull, the atlas and axis, as well as muscles and connective tissues that attach the skull to the cervical spine. The CCJ encloses the central nervous system (CNS), encephalic vasculature and the cerebrospinal fluid (CSF) system. The CCJ spans the brainstem to the spinal cord, including the vascular system as well as connecting the cerebrospinal fluid (CSF) cisterns within the skull to the CSF channels in the spinal canal. Malformation and misalignment of the craniocervical junction can cause a constellation of cerebral and other neurological signs and symptoms collectively called craniocervical syndrome (CCS). The signs and symptoms of craniocervical junction syndrome may be due to mechanical strain causing deformation of dura mater, vasculature and other structures of the cranial vault resulting in irritation of and dysfunction of affected tissues. Deformation of the CCJ may also obstruct blood and CSF flow. Chronic ischemia, edema and hydrocephalus can cause degenerative cascades that can in turn lead to neurodegenerative diseases.

Craniocervical Misalignment Masquerading as Facial Pain: Options for Diagnosis and Management

“…The cervical spine is made up of seven vertebrae divided into upper and lower sections. The upper cervical spine is composed of the first two vertebrae, classically named the atlas and axis [1]. The term craniocervical junction is used to describe the area that includes the base of the skull (occiput), the atlas, the axis, part of the brainstem and spinal cord, the vasculature in and out of the brain, as well as the muscles and connective tissues that act to stabilize it.…”

Craniocervical Junction Visualization and Radiation Dose Consideration Utilizing Cone Beam Computed Tomography for Upper Cervical Chiropractic Clinical Application a Literature Review

“…Within the chiropractic profession there exists a sub-specialty, called Upper Cervical Chiropractic (UCC) which concentrates on the craniocervical junction and how the structural integrity of the neck influences the nervous system, vascular system and cerebrospinal fluid flow in and out of the cranial vault. 2 , 3 CBCT imaging offers a high quality imaging technique that minimizes radiation exposure to patients, and this type of imaging is of particular interest to UCC practitioners. Figure 1 demonstrates neutral lateral radiograph typical in an upper cervical chiropractic clinical setting.…”

“… 6 The complex nature of the structure and function of the craniocervical junction makes it particularly vulnerable to injury and deformation, as forces acting upon the head and cervical spine may occur in complex patterns. 3 …”

“…Misalignments, malformation, and anomalies of the CCJ have been shown to obstruct flow through the vertebral arteries. 3 , 6 , 9 According to Ref. [ 9 ], the hydrodynamics of arteries, veins, and cerebrospinal fluid influence the pressure gradients that occur within an essentially closed cranial vault that has little room for expansion.…”

“…This potential “choke point” at the CCJ for fluid flow may play a role in neurodegenerative disorders and conditions affecting brain health. 3 , 6 , 9 …”