The document summarizes the structure and function of the spine. It describes the general structure of the vertebral column including the 33 vertebrae and 23 intervertebral discs. It then discusses the specific regions and curves of the spine. It provides details on the structure and function of the cervical region including the unique features of the atlas and axis bones. It also summarizes the ligaments, joints, range of motion, and importance of the spine in supporting the head and enabling movement.
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THE SPINE (cervical spine)
1. THE SPINE
PRESENTED BY-KHUSHBOO ANJUM
MPT NEUROLOGY 1ST SEMESTER
DEPARTMENT OF PHYSIOTHERAPY
SCHOOL OF HEALTH SCIENCE
C.S.J.M.U, KANPUR
2. GENERAL STRUCTURE AND STRUCTURE
• The vertebral column
resembles a curved rod,
composed of 33
vertebrae and 23
intervertebral discs.
• The vertebral column is
divided into the
following five regions:
cervical, thoracic,
lumbar, sacral, and
coccygeal.
3.
4.
5. THE CURVE OF THE VERTEBRAL COLUMN
• Fetal life-convex posteriorly. (FIG-A)
• Adult-PRIMARY CURVE &
SECONDARY CURVE
• {The two curves (thoracic and sacral)
that retain the original posterior
convexity throughout life are called
primary curves, whereas the two
curves (cervical and lumbar) that
show a reversal of the original
posterior convexity are called
secondary curves.}
• Curves that have a posterior
convexity (anterior concavity) are
referred to as kyphotic curves;
curves that have an anterior
convexity (posterior concavity) are
called lordotic curves.
• A curved vertebral column provides
significant advantage over a straight
rod in that it is able to resist much
higher compressive loads.
6. STRUCTURE OF THE CERVICAL REGION
• The cervical vertebral column consists of seven
vertebrae in total.
• Morphologically and functionally, the cervical
column is divided into two distinct regions: the
upper cervical spine, or craniovertebral region,
and the lower cervical spine.
• The craniovertebral region includes the occipital
condyles and the first two cervical vertebrae, C1
and C2, or, respectively, the atlas and axis.
• The lower cervical spine includes the vertebrae
of C3 to C7. The vertebrae from C3 to C6 display
similar characteristics and are therefore
considered to be the typical cervical vertebrae.
• The atlas, axis, and C7 exhibit unique
characteristics and are considered the atypical
cervical vertebrae.
• All of the cervical vertebrae have the unique
feature of a foramen (transverse foramen) on
the transverse process, which serves as passage
for the vertebral artery.
7. CRANIOVERTEBRAL REGION
• ATLAS- The atlas is different from other vertebrae
in that it has no vertebral body or spinous
process and is shaped like a ring (Fig. 4-22).
The atlas also possesses a facet on the
internal surface of the anterior arch for
articulation with the dens (odontoid
process) of the axis.
8. AXIS- The axis is atypical in that the anterior
portion of the body extends inferiorly and a
vertical projection called the dens arises from
the superior surface of the body (Fig. 4-23)
9. 7TH CERVICAL VERTEBRA / VERTEBRA PROMINENS
• The 7th cervical vertebra, (C7) is the
largest and most inferior.
• This spinous process can be easily seen
and felt at the base of the neck, making it
a prominent landmark of the
skeleton (giving the C7 the name vertebra
prominens).
• spinous process ends in a rounded
tubercle and is not bifid.
• C7 transverse foramina are small, and do
not transmit the vertebral artery.
10. ARTICULATIONS
• The two atlanto-occipital joints consist of the two
concave superior zygapophyseal facets of the atlas
articulating with the two convex occipital condyles of
the skull.
• These joints are true synovial joints with intra-
articular fibroadipose meniscoids.
• There are three synovial joints that compose the
atlantoaxial joints: the median atlantoaxial joint
between the dens and the atlas and two lateral
joints between the superior zygapophyseal facets of
the axis and the inferior zygapophyseal facets of the
atlas.
11. CRANIOVERTEBRAL LIGAMENTS
• TRANSVERSE LIGAMENT-
•The transverse ligament
stretches across the ring of
the atlas and divides the ring
into a large posterior section
for the spinal cord and a small
anterior space for the dens.
•The transverse ligament and
its longitudinal bands are
sometimes referred to as the
atlantal cruciform ligament.
12. MAJOR LIGAMENTS OF VERTEBRAL COLUMN
LIGAMENTS FUNCTIONS REGION
Anulus fibrosus
(outer fibers)
Anterior longitudinal
ligament
Resists distraction,
translation, and
rotation of vertebral
bodies.
Limits extension and
reinforces
anterolateral portion of
anulus
fibrosus and anterior
aspect of
intervertebral joints.
Limits extension
Cervical, thoracic, and
lumbar.
C2 to sacrum but well
developed in cervical,
lower thoracic, and lumbar
regions.
Anterior atlantoaxial
(continuation of the
anterior longitudinal,
ligament)
Limits extension. C2 to the occipital bone
13. LIGAMENTS FUNCTIONS REGION
Posterior longitudinal
ligament
Limits forward flexion and
reinforces posterior portion
of the anulus fibrosus.
Axis (C2) to sacrum. Broad
in the cervical and thoracic
regions and narrow in the
lumbar region.
Tectorial membrane
(continuation of the
posterior longitudinal
ligament
Limits forward flexion Axis (C2) to occipital bone
Ligamentum flavum Limits forward flexion,
particularly in
the lumbar area, where it
resists
separation of the laminae
Axis (C2) to sacrum. Thin,
broad, and long in
cervical and thoracic
regions and thickest in
lumbar region
Supraspinous ligaments Limit forward flexion Thoracic and lumbar (C7–L3
or L4). Weak in
lumbar region.
Ligamentum nuchae Limits forward flexion. Cervical region (occipital
protuberance to C7)
14. • ALAR LIGAMENTS-
•The two alar ligaments are also specific to the cervical
region (see Fig. 4-27). These paired ligaments arise
from the axis on either side of the dens and extend laterally
and superiorly to attach to roughened areas on
the medial sides of the occipital condyles55 and to the
lateral masses of the atlas.
•These ligaments are relaxed with the head in midposition
and taut in flexion.
• Axial rotation of the head and neck tightens both alar
ligaments.
Crisco JJ, Panjabi MM, Dvorak, J: A model of the
alar ligaments of the upper cervical spine in axial
rotation. J Biomech 24:607, 1991.
16. THE LOWER CERVICAL REGION
TYPICAL CERVICAL VERTEBRA
• BODY-
The body of the cervical vertebra is small, with a transverse
diameter greater than anteroposterior diameter and height.
• ARCHES-
Pedicles. The pedicles project posterolaterally and are
located halfway between the superior and inferior surfaces
of the vertebral body.
Laminae. The laminae are thin and slightly curved.They
project posteromedially.
Zygapophyseal Articular Processes (Superior and
Inferior). The processes support paired superior facets
that are flat and oval and face superoposteriorly.
17. • Transverse Processes. A foramen is located in the transverse processes
bilaterally for the vertebral artery, vein, and venous plexus. Also, there is a groove for
the spinal nerves.
• Spinous Processes. The cervical spinous processes are short, slender, and
extend horizontally. The tip of the spinous process is bifid. The length of the spinous
processes decreases slightly from C2 to C3, remains
constant from C3 to C5, and undergoes a significant increase at C7.
• Vertebral Foramen. The vertebral foramen is relatively large and
triangular.
18. FUNCTIONS OF CERVICAL REGION
KINEMATICS
• The atlanto -occipital joint is a
plane synovial joint that
permits flexion -extension,
some axial rotation, and
lateral flexion.
• Flexion-extension takes place
in the sagittal plane around a
medial-lateral axis.
• Axial rotation takes place in
the transverse plane around a
vertical axis and lateral flexion
takes place in the frontal plane
around an anterior-posterior
axis.
19. ARTHOKINEMATIC
• At the atlanto-occipital joint,
the inferior convex condyles of
the occiput articulate with the
two superior concave
zygapophyseal articular facets
of the lateral bodies of the
atlas. When the head moves
on the atlas ( convex surfaces
moving on the concave
surface) ,the occipital condyles
glide in direction opposite to
the movement of the top of
the head. In flexion, the
condyles glide posteriorly on
the atlas articular surfaces. In
extension the occipital
condyles glide anteriorly on
the atlas , whereas the back of
the head moves posteriorly.
20. FUNCTIONS OF CERVICAL SPINE
• The cervical spine plays many roles in the head-neck area,
including:
• Protection of the spinal cord: It is
a bundle of nerve fiber that is a continuation of the brain stem. The
spinal cord transverse through a canal in the vertebral column
called the spinal canal. The cervical spine protects it from external
compression.
• Provide support to the head:
The cervical spine holds the head in position and bears its weight.
• Supports blood supply to the brain:
The cervical spine carries a vertebral artery in its transverse
foramen and helps them to send blood to the brain.
• Supports Head-Neck movements: Cervical spine, along with the
neck muscle, provides a wide range of motion in this region.
REHMAN S,DAS J M ,ANATOMY,HEAD AND
NECK,CERVICAL SPINE,2021
22. A TYPICAL VERTEBRA
• The structure of a typical
vertebra consists of two
major parts: an anterior,
cylindrically shaped
vertebral body and a
posterior, irregularly
shaped vertebral or neural
arch.
• The vertebral body is
designed to be the weight-
bearing structure of the
spinal column. It is suitably
designed for this task, given
its block like shape with
generally flat superior and
inferior surfaces.
24. INTERVERTEBRAL DISC
• The intervertebral disc has two
principle functions: to separate
two vertebral bodies, thereby
increasing available motion, and
to transmit load from one
vertebral body to the next.
• The disc thickness varies from
approximately 3 mm in the
cervical region, where the
weight-bearing loads are the
lowest, to about 9 mm in the
lumbar region, where the
weight-bearing loads are the
greatest.
• The discs are smallest in the
cervical region and largest in the
lumbar region.
25. • The intervertebral disks
are composed of three
parts: (1) the nucleus
pulposus, (2) the anulus
fibrosus , and (3) the
vertebral end plate.
• All three structures are
composed of water,
collagen, and
proteoglycans (PGs);
however, the
relativeproportions of
each vary.
26. ARTICULATIONS
• Two main types of articulations are found
in the vertebral column:
cartilaginous joints of the symphysis type
between the vertebral bodies, including
the interposed discs, and diarthrodial, or
synovial, joints between the
zygapophyseal facets located on the
superior articular processes of one
vertebra and the zygapophyseal facets on
the inferior articular processes of an
adjacent vertebra above. The joints
between the vertebral bodies are referred
to as the interbody joints. The joints
between the zygapophyseal facets are
called the zygapophyseal (apophyseal or
facet) joints . Synovial joints also are
present where the vertebral column
articulates with the ribs, with the skull,
and with the pelvis at the SIJs.
27. LIGAMENTS AND JOINT CAPSULES
• Six main ligaments are
associated with the
intervertebral and
zygapophyseal joints.
They are the
• Anterior longitudinal
• Posterior longitudinal
ligaments and PLL;
• Ligamentum flavum;
• Interspinous
• Supraspinous
• Intertransverse
ligaments .
28. • Anterior and posterior
longitudinal ligaments-The
anterior longitudinal
ligament runs along the
anterior and lateral
surfaces of the vertebral
bodies from the sacrum to
the second cervical
vertebra. The ligament is
compressed in flexion( Fig.
A) and stretched in
extension (see Fig. B).
• The PLL runs on the posterior
aspect of the vertebral bodies from
C2 to the sacrum and forms the
ventral surface of the vertebral
canal. It also consists of at least two
layers: a superficial and a deep
layer.
29.
30. FUNCTION
KINEMATICS
• The motions available to
the column as a whole are
flexion and extension,
lateral flexion, and rotation.
• These motions are often
coupled motions.
• The intervertebral discs
increase movement
between two adjacent
vertebrae. If the vertebrae
lay flat against each other,
the movement between
them would be limited to
translation alone.
• This arrangement adds
tremendous range of
motion.
Bogduk N: Clinical Anatomy of the Lumbar
Spine and Sacrum, 3rd ed. New York,
Churchill Livingstone, 1997.
31. • FLEXION
In vertebral flexion, anterior
tilting and gliding of the
superior vertebra occur and
cause widening of the
intervertebral foramen and
separation of the spinous
processes.
• EXTENSION
In extension, posterior
tilting and gliding of the
superior vertebra occur and
cause narrowing of the
intervertebral foramen, and
the spinous processes move
closer together.
32. LATERAL FLEXION
• In lateral flexion, the superior
vertebra laterally tilts ,rotates ,
and translates over the adjacent
vertebra below.
33. KINETICS
• The vertebral column is subjected to axial
compression , tension, bending, torsion, and
shear stress not only during normal functional
activities but also at rest.
. Gracovetsky SA: The resting spine: A conceptual approach to the
avoidance of spinal reinjury during rest. Phys Ther 67:549, 1987.