We would all like to thank Dr. Richard C. Schafer, DC, PhD, FICC for his lifetime commitment to the profession. In the future we will continue to add materials from RC’s copyrighted books for your use.
The following is Chapter 7 from RC’s best-selling book:
“Clinical Biomechanics: Musculoskeletal Actions and Reactions”
The following materials are provided as a service to our profession. There is no charge for individuals to copy and file these materials. However, they cannot be sold or used in any group or commercial venture without written permission from ACAPress.
Chapter 7: CLINICAL BIOMECHANICS OF THE CERVICAL SPINE
This chapter considers those factors that are of biomechanical and related clinical interest imperative to the satisfactory evaluation of common or not infrequent cervical syndromes. The discussion assumes that the physician is skilled in taking a thorough clinical history and performing the basic physical, orthopedic, neurologic, and roentgenographic examination procedures. The kinesiology and kinematics of the neck, the effects and mechanisms of cervical trauma, and a number of clinical problems are discussed that are pertinent to the diagnosis and management of musculoskeletal cervical disorders.
Background
The viscera of the neck serve as a channel for vital vessels and nerves, the trachea, esophagus, spinal cord, and as a site for lymph and endocrine glands. The cervical spine provides musculoskeletal stability and support for the cranium, and a flexible and protective column for movement, balance adaptation, and housing of the spinal cord and vertebral artery. When the head is in balance, a line drawn through the nasal spine and the superior border of the external auditory meatus will be perpendicular to the ground.
Cervical subluxations may be reflected in total body habitus, and insults can manifest themselves throughout the motor, sensory, and autonomic nervous systems. Many peripheral nerve symptoms in the shoulder, arm, and hand will find their origin in the cervical spine. Nowhere in the spine is the relationship between the osseous structures and the surrounding neurologic and vascular beds as intimate or subject to disturbance as it is in the cervical region.
Many of the skeletal landmarks readily observed in the thin individual are frequently obscured in the obese (Fig. 7.1). Except for the manatee and some sloths, all mammals have seven cervical vertebrae.
Kinesiology of the Neck
The cervical spine is a miracle in design and structure as it moves in various planes. It must support the head, and it must move the eyes and the ears for various sensory orientations.
Mechanically, the head teeters on the atlanto-occipital joints, shaped like cupped palms tipped slightly medially. Because the line of gravity falls anterior to these articulations, a force must be constantly provided in the upright posture by the posterior neck muscles to hold the head erect. Added to this gravitational stress is the action of the anterior muscles of the neck, essentially the masticatory, suprahyoid, and infrahyoid groups, which as a chain join the anterior cranium to the shoulder girdle.
Flexion, extension, rotation, lateral flexion, and circumduction are the basic movements of the cervical region. Movements of the head on the neck are generally confined to the occiput-atlas-axis complex and can be described separately from movements of the neck on the trunk. The prime movers and accessories involved in neck motion are listed in Table 7.1.
Table 7.1. Neck Motion
| You may review the complete Chapter (including sketches and Tables) at the ACAPress website |
