Download Vertebral Column

KUWAIT UNIVERSITY
FACULTY OF MEDICINE
DEPARTMENT OF ANATOMY
210-Anatomy
T. Chacko Mathew, M.Sc.
Ph.D., FRCPath (UK)
The Vertebral Column
OBJECTIVES:
• At the end of the lecture the students should be able to
describe
• The structure and functions of the vertebral column (regions,
number of vertebrae in each region)
• The primary and secondary curves of the vertebral column
• Structure of a typical vertebra
• Structure of atypical vertebrae
• Zygapophyseal joint, atlanto-occipital joint and atlanto-axial
joint
• Structure and function of the inter-vertebral disc
• Common injuries and deformities of the vertebral column
The vertebral column is composed
of a series of 33 separate bones
known as vertebrae.
• There are seven cervical or
neck vertebrae,
• 12 thoracic vertebrae,
• Five lumbar vertebrae.
• The sacrum is composed of
five fused vertebrae,
• There are four coccygeal
vertebrae (Lower three are
commonly fused).
THE VERTEBRAL COLUMN
FUNCTIONS:
• Strong
Serves flexible
as a point
rod
ofproviding
movement of
attachment
forthe
ribs
trunk.
and
as anand
axisprotects
of the the
• acts
Encloses
body.
spinal cord and the spinal
• Plays
nervean
roots.
important role
maintaining
• in
It supports
the the
head and acts
posture
of the body and
as a pivot.
locomotion.
CURVATURES OF THE
VERTEBRAL COLUMN
• 2 primary (thoracic and
sacro-coccygeal)
• 2 secondary curvatures
(cervical and lumbar).
• These curves are called the
cervical, thoracic, lumbar, and
pelvic curves.
NORMAL CURVATURES OF THE
VERTEBRAL COLUMN
• In the early embryo,
the vertebral column
is C-shaped; pre-natal
and post-natal growth
accounts for 4 distinct
curvilinear regions in
the adult
Primary curvatures:
posterior convexities
• Present at birth; relatively
immobile because of
attachments to other skeletal
components (rib cage and
pelvis)
– Thoracic
– Sacral
Secondary curvatures:
anterior convexities
• Develop after birth;
relatively flexible
because of lack of other
skeletal connections
• These curves allow
human beings to stand
upright and help to
maintain the balance of
the upper body.
Secondary curvatures:
anterior convexities
• The cervical and lumbar
curves are not present in an
infant.
• The cervical curves forms
around the age of 3 months
when an infant begins to hold
its head up and the lumbar
curve develops when a child
begins to walk.
ABNORMAL
CURVATURES OF
THE VERTEBRAL
COLUMN
Kyphosis
• Exaggerated posterior
curvature, generally in
the thoracic region (a
"humpback")
Lordosis
• Exaggerated anterior
curvature, generally in the
lumbar region (a
"swayback")
temporary lordosis is
common among pregnant
women
Scoliosis
• Lateral curvature.
• Most common abnormal
curvature, occurring in 0.5% of
the population; more common
among females
• may result from unequal
growth of the two sides of one
or more vertebrae
Structure of
a typical
vertebra
Each typical
vertebra consists
of an anterior body
which joins with the
vertebral arch
posteriorly
via short rounded
bars, the pedicles.
The body is
made of
strong, thick,
spongy bone
which resists
compression.
•
•
The arch bears 7
processes which
mainly provide
movement or
muscular
attachments.
These processes are:
1. a pair of transverse
processes,
2. a pair of superior
articular processes
3. a pair of inferior
articular processes
4. a spinous process.
•
The superior and
inferior articular
processes bear
superior and
inferior articular
facets to form
synovial joints.
•
The spinous
process is
formed by the
union of two flat
leaf like oblong
plates of bone
with sloping
surfaces, called
the laminae.
lamina
lamina
•
The pedicles on their
upper and lower
surfaces form superior
and inferior vertebral
notches
which ultimately
contribute to the
formation of
intervertebral foramen
containing the spinal
nerve and its blood
vessels.
•
Encircled by the
body anteriorly,
vertebral arch
• The vertebral
posteriorly and the
foramina of the
pedicles laterally
successive
is the vertebral
vertebrae form the
foramen, which
vertebral canal
lodges the spinal
cord with its
membranes and
blood vessels.
ATYPICAL
VERTEBRAE
•
The first cervical
vertebra is known as
the atlas.
• It has no body.
• It contains an anterior
tubercle instead.
• Its superior articular
facets articulate with
the occipital condyles
of the skull.
• The head thus moves
forward and
backwards on this
vertebra.
•
•
•
The second cervical vertebra
is known as Axis
• It contains a prominent
odontoid process, a tooth-like
structure that projects
superiorly from the body to
articulate with the anterior
arch of the atlas
It articulates with the anterior
tubercle of the atlas, forming
a pivotal joint.
Side to side movements of the
head take place about this
joint.
•
The seventh cervical vertebra is sometimes
considered atypical since it lacks a bifid
spinous process.
VERTEBRAL PROCESSES
7 IN NUMBER ON
TYPICAL VERTEBRAE
Spinous Processes
(1 per vertebra)
•
project posteriorly
or posteroinferiorly
in the median plane
arise from the point
of union of left and
right laminae
provide attachment
for interspinous and
supraspinous
ligaments and
several muscles
Transverse Processes
(2 per vertebra: left and right)
•
• Extend
posterolaterally
from the point of
union of pedicles
and laminae
Provide attachment
for intertransverse
ligaments and
several muscles
Articular Processes
(Zygapophyses)
(4 per vertebra)
•
Left and right, superior
and inferior
• also arise from the
junction of pedicles
and laminae
• Superior processes
project superiorly and
inferior processes
project inferiorly (with
characteristic regional
variations).
Articular Processes
(Zygapophyses)
(4 per vertebra)
•
Each articular process
bears a facet which
articulates with a facet
of an adjacent
vertebrae to form a
zygapophyseal (facet)
joint
JOINTS
Zygapophyseal
(facet) joints
joints between
articular processes
of adjacent
vertebral arches
permit gliding
movements
between vertebrae
Atlanto-occipital
joints
• superior articular facets of
the atlas are concave and
kidney-shaped to receive
the occipital condyles of
the skull
• facilitate nodding (flexion)
of the head
Atlanto-axial joint
• The dens of the axis (C2)
articulates with the body of
the atlas (C1)
• Facilitates pivoting of the
head
INTER-VERTEBRAL
DISC
The bodies of adjacent
vertebrae are
connected by
specialized
cartilaginous joints
known as
intervertebral discs.
Each discbody
is composed
Normally
weight
ofisa transmitted
central core of
gelatinous
through
the material,
disc by
known
the
loading
theas
nucleus
nucleus pulposus,
pulposus,
which is
and
surrounding
thena compressed
series
of fibrous
and
transfers
its
rings
known
as the
loading
to the
annulusfibrous.
fibrosis
annulus
In most individuals, the
fibers of the annulus
fibrosus effectively
resist this load, but in
some people they do
not and the nucleus
pulposus is forced out
of the disc, or is
herniated.
A herniated nucleus
pulposus can have a
profound effect on the
adjacent spinal nerves
Two ligaments connect
the vertebral bodies
anteriorly and
posteriorly and
thereby reinforce
the intervertebral
disc.
1. The anterior
longitudinal ligament
is strong and robust
throughout
But the posterior
longitudinal ligament
becomes thin and
narrow in the lumbar
region. This change in
structure of the posterior
longitudinal ligament is
part of the reason that
the overwhelming
majority of disc
herniations occur
posteriorly in the lumbar
region.
INJURIES AND
DEFORMITIES OF THE
VERTEBRAL COLUMN
SPONDYLYSIS; SPONDYLOSIS
Chronic degenerative disease of
intervertebral discs and/or vertebral
bodies. May compress spinal cord,
nerves, or roots. If symptoms present,
most often present as radiculopathies
SPINAL CORD TRANSECTION
Results in loss of all sensation and voluntary
movement inferior to the lesion
• Paraplegia: Paralysis of lower body
including both lower extremities
Results from spinal cord transection between
cervical and lumbosacral enlargements
• Quadriplegia: Paralysis of all four limbs.
Results from spinal cord transection superior
to C3
SCIATICA
•
•
Pain resulting from
irritation of the
sciatic nerve
Usually caused by
compression or
trauma to the
sciatic nerve or its
roots
RADICULOPATHIES
•
•
Shooting pain that radiates down one or both
legs in a dermatomal distribution, often with
associated sensory and motor impairment
Usually caused by compression or stretching
of spinal nerves or roots
OSTEOPOROSIS
• Most common in
postmenopausal women
• Loss of endogenous
estrogen leads to severe
decrease in vertebral bone
density, due to
demineralization
• Characterized by dorsal
kyphosis - Commonly
presents medically as a
vertebral compression
fracture. Can be prevented
or slowed by hormone
replacement therapy.