We include an extensive chapter on this subject in recognition
of the fact that back pain is among the most frequent of medical
complaints. Up to 80 percent of adults have low back pain at some time
in their lives and, according to Kelsey and White, an even larger
percentage will be found at autopsy to have degenerative disc disease.
The diagnosis of pain in these parts of the body often requires
the assistance of a neurologist. One task is to determine whether
a disease of the spine has compressed the spinal cord or the spinal
roots. To do this effectively, a clear understanding of the structures
involved and some knowledge of orthopedics and rheumatology is necessary.
As pains in the lower part of the spine and legs are caused by
different types of disease than those in the neck, shoulder, and
arms, they are considered separately.
The lower parts of the spine and pelvis, with their massive muscular
attachments, are relatively inaccessible to palpation and inspection.
Although some physical signs and imaging studies are helpful, diagnosis
often depends on the patient’s description of the pain
and his behavior during the execution of certain maneuvers. Seasoned
clinicians appreciate the need for a systematic inquiry and method
of examination, the descriptions of which are preceded here by a
brief consideration of the anatomy and physiology of the spine.
Physiology of the Lower Part of the Back
The bony spine is a complex structure, roughly divisible into
an anterior and a posterior part. The anterior component consists
of cylindric vertebral bodies, articulated by the intervertebral
discs and held together by the anterior and posterior longitudinal
ligaments. The posterior elements are more delicate and extend from
the bodies as pedicles and laminae, which form the spinal
canal by joining with the posterior aspects of the vertebral
bodies and ligaments. Large transverse and spinous processes project
laterally and posteriorly, respectively, and serve as the origins
and insertions of the muscles that support and protect the spinal
column. The bony processes are also held together by sturdy ligaments,
the most important being the ligamentum flavum, which runs along the
ventral surfaces of the posterior elements and is applied to the
inner surface of the laminae. The posterior longitudinal ligament
lies opposite it on the dorsal surfaces of the vertebral bodies. These
two ligaments bound the posterior and anterior structures of the
spinal canal, respectively. The posterior parts of the vertebrae
articulate with one another at the diarthrodial facet joints (also
called apophysial or zygapophysial joints), each of which is composed
of the inferior facet of the vertebra above and the superior facet
of the one below. Figures 11-1 and 11-2 illustrate these anatomic features.
The facet and sacroiliac joints, which are covered by synovia, the
compressible intervertebral discs, and the collagenous and elastic
ligaments, permit a limited degree of flexion, extension, rotation,
and lateral motion of the ...