Chapter 9 Anatomy, Imaging, and Common Pain-Generating Degenerative Pathologies of the Spine Flashcards
Components of Spinal Column
The spinal column is comprised of 7 cervical, 12 thoracic,
5 lumbar, and 5 fused sacral segments. The terminal portion
of the osseous spinal column, the coccygeal segments,
varies in number, but typically 4 segments can be visualized
C1 level (the atlas)
comprised of an anterior arch, posterior arch, and paired lateral
masses. The lateral masses articulate with the occipital condyles superiorly and the body of C2 inferiorly. C1 does not have a vertebral body nor
is it separated from adjacent levels by an intervertebral
disc
C2 vertebra (the axis)
unique in having a superior
extension of bone from the vertebral body that articulates
with the dorsal margin of the anterior arch of C1: this
bony projection is called the odontoid process or dens and
allows for head rotation
Unique to the segments
from C3 through C7
are the uncinate processes that
arise from the dorsolateral margins of the superior end
plates of the vertebral bodies and articulate with the level
above
Parts of the vertebrae
The typical cervical, thoracic, and lumbar vertebrae consist of an anterior body, paired pedicles, articular pillars
and laminae, and a single dorsal midline spinous process
Pedicle
The pedicles attach the body to the posterior neural elements.
Articular Pillars
The articular pillars are comprised of the pars interarticularis and the superior and inferior articular processes. Each level from C3 to L5 has superior and inferior
articular processes that serve as the main posterior contact between adjacent levels. The surface of the superior articular process is the inferior facet of the associated zygapophyseal joint, and the surface of the inferior articular process is the superior facet of the joint.
“superior processes”
“inferior process”
The “superior processes” at C1 and C2 and the “inferior process” at C1 are more descriptively referred to as articular surfaces, as
they do not have a true morphological extension away
from the vertebral segments
laminae
The two laminae extend dorsomedially and connect to form the root of the spinous process.
spinous process
The spinous process projects dorsally and serves as an attachment point for the posterior ligamentous structures
Function of pedicles, articular pillars, and lamina
The pedicles, articular pillars, and lamina serve to enclose and protect the spinal canal and contents, particularly the spinal cord and nerve roots
Transverse processes
In the mid-cervical spine, the transverse processes help to enclose and form the osseous transverse foramina that transmit the vertebral artery and contents. In the thoracic and lumbar spine, the transverse processes serve as anchoring points for the muscles that help to stabilize and protect the spinal column and its contents
Six specific types of synovial joints exist from the skull
base to the lumbosacral junction
including the atlantooccipital,
atlantoaxial, uncovertebral, costovertebral, costotransverse,
and zygapophyseal (facet) joints
The atlanto-occipital joint is formed by
the bilateral superiorly convex occipital condyles and the bilateral concave superior articular surfaces of the C1 lateral masse
The main atlantoaxial joint is formed by
the inferior articular surfaces of C1 and the superior articular surfaces of C2
A true synovial-lined joint
A true synovial-lined joint also exists between the ventral dens and the dorsal surface of the
C1 anterior arch, and the dorsal aspect of the dens and the
posterior ligamentous structures.
uncovertebral joints (joints of Luschka)
The uncovertebral joints (joints of Luschka) exist only in the cervical spine below C2. The joints of Luschka have features of both cartilaginous and synovial joints and when degenerated can result in foraminal stenosis and even central stenosis
osseous uncinate processes
The osseous uncinate processes arise from
the dorsolateral margin of the superior end plates of the
C3–C7 vertebral bodies and articulate with the level
above: uncovertebral joints therefore exist from C2–C3 to
C6–C7
costovertebral and costotransverse joints
the costovertebral and
costotransverse joints are articulations between the ribs
(costo-) and the vertebral bodies or transverse processes
of the thoracic spine
facet joints
The facet joints are formed by the inferior and superior articular processes of adjacent vertebral bodies.The facet surfaces
(named relative to the joint space as described below)
are covered with articular cartilage that allows for bending
motion and offers some protection to shearing forces. The joints are encapsulated by a true synovial lining and loose
capsular ligaments.
fibrous capsule
In the cervical spine, there is a thick fibrous capsule laterally under which a small synovial
recess may protrude. In the lumbar spine, a thick fibrous
capsule is present along the posterior margin of the facet
joint.
inferior synovial recess
The inferior synovial recess occurs at the caudal extent of this capsule and is the common location for access to the joint space.
facet joints innervation
the facet joints are dually innervated from paired medial branches of the dorsal primary rami. This dual innervation explains why complete denervation of a symptomatic facet joint requires treatment of both medial branches
orientation of
cervical facet joints,
thoracic facet joints,
lumbar facet joints
The cervical facet joints are obliquely oriented from superior to posterior with a ventral to dorsal angle when viewed in the sagittal plane. The thoracic facet joints are oriented in the coronal plane limiting access for percutaneous procedures
The lumbar facet joints have a lunate configuration
with the posterior margin oriented in the oblique sagittal plane and the anterior margin oriented in the oblique coronal plane
Transverse Foramen
The transverse foramen, also known as the vertebral
foramen or foramen transversarium, occurs in the cervical spine from C1 to C7. The contents of the transverse foramina include the vertebral artery, vertebral venous plexus, fibers of the sympathetic chain, and fat.
Vertebral Artery
The vertebral artery
typically enters the foramen at C6, but can enter as high
as C3. In the sagittal projection, the vertebral artery is a few millimeters ventral to the adjacent exiting nerve root
The exiting cervical nerves are how in the intervertebral foramina?
The exiting cervical nerves are positioned posteroinferiorly
in the intervertebral foramina
Small veins connecting the epidural venous plexus and the anterior longitudinal intraspinal venous channel with the
perivertebral venous plexus within the transverse foramina
traverse the intervertebral foramen
How many cervical nerve roots?
There are eight paired cervical nerve roots,
the first paired cervical nerve root exit the spinal canal btw
the skull base and C1
In the cervical spine, how are the nerve root numbered?
in the cervical spine, the number of the nerve root passing through the foramen is one greater than the number of the pedicle that it passes beneath. For example, the nerve root passing through the intervertebral foramen at C3–C4 is the C4 nerve root
In the thoracic spine, how are the nerve root numbered?
The exiting nerve roots
are designated by the pedicle under which they immediately
course. For example, at the T8–T9 level, the T8 spinal nerve root exits.
In the cervical spine, how is the spinal nerve root oriented?
The exiting cervical nerves are positioned posteroinferiorly
in the intervertebral foramina
In the thoracic spine, how is the spinal nerve root oriented?
The thoracic
spinal nerves are more closely associated with the
superiorly positioned articular process compared to the
cervical spine. Small veins run through the intervertebral
foramina as in the cervical spine
In the lumbar spine, how is the spinal nerve root oriented?
The spinal nerve roots exit at a 45° angle inferolaterally and are
closely associated with the medial and inferior margins of
the pedicle under which they exit
