![]() The more common cervical lordotic curve allows for greater distribution of weight-bearing forces brought upon by the weight of the head and leads to the distribution of forces throughout the lower cervical region. The normal cervical alignment can vary from lordotic to neutral to kyphotic depending on a patient’s normal global spinal alignment. The rest of the cervical spine from C3 to C7 exhibits uniform properties with gradual enlargement of the vertebral bodies as one descends lower in the subaxial spine. C1 has no vertebral body (centrum) and articulates with odontoid process of C2 anteriorly ( 3). When considering the placement of internal fixation into the occiput, particular attention must be given to the vertebral foramen and thickness of the keel of the occipital bone to avoid vascular/neurologic injury. This region of the spine exhibits unique anatomy and biomechanics that differ from the subaxial cervical spine. The superior craniocervical spine is comprised of the cranium, C1 (atlas), and C2 (axis). While these parts are common between each of the levels of the spine, unique properties emerge in specific regions creating variations in motion and predisposition to certain pathologies. Each vertebra can be separated into three functional parts: the vertebral body/intervertebral discs, the spinal canal, and the transverse/spinous processes/facet joints ( 2). Classically, the spine is separated into 5 regions consisting of: 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, 5 fused sacral vertebrae, and the 4 fused bones of the coccyx. ![]() While primarily functioning to protect the spinal cord from significant impact and injury, it also functions to support the weight-bearing forces of the body and aid in mobility/flexibility. The spine, or vertebral column, is a network of 33 bones, separated/cushioned by intervertebral discs, and stabilized by surrounding ligaments/musculature. The aim of our review is to investigate the anatomic/physiologic variations of global spine alignment and its impact on cervical spine pathology, as well as patient-reported outcomes (PRO).Ĭervical/global spine anatomy and biomechanics Moreover, the recent literature has examined the relationship of cervical alignment to the alignment of the thoracolumbar spine and the importance of considering the entire spinal axis in surgical decision making. While studies have predominantly focused on the lumbosacral-pelvic axis, recent interest in the field of cervical spine pathology/deformity has emphasized the importance of cervical sagittal alignment and its impact on symptomatology and surgical planning. The Debousset theory ( 1) of the “conus of economy” stressed the importance of spinopelvic balance in providing a framework to maintain an upright posture and exert minimal effort/energy expenditure. ![]() Similarly, improvements in bone graft substitutes such as bone morphogenetic protein and grafting materials have helped to improve fusion success rates once spinal alignment is optimized. Novel innovations in surgical techniques, including segmental instrumentation, interbody cages, and a variety of osteotomy techniques have all been designed to help contribute to overall spinal stability and improved spine alignment. With the emergence of modern technology and advanced surgical techniques, the importance of understanding global spine alignment has evolved as a critical pillar in determining severity of spinal pathology and operative decision-making. ![]()
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