4. MOB TCD
Typical Vertebrae
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Basic parts
Body
Neural arch consists of
Pedicles
Lamina fuse posteriorly to
form spine
• Transverse processes arise
from pedicles
• Superior and inferior articular
processes
5. MOB TCD
Typical Thoracic Vertebrae
• Typical thoracic are 2-9
• Body is heart shaped and
vertebrae increase in size from
the fourth thoracic vertebra down
• Foramina for basi-vertebral veins
posterior aspect of bodies
• Lower vertebrae have broader
bodies
• There are single facets on bodies
of T10, T11, and T12
6. MOB TCD
Typical Thoracic Vertebrae 2-9
• Two costal demi-facets on
the body and an articular
facet on the transverse
processes
• Superior and inferior facets
in coronal plane
• Superior articular facets are
flat and face posteriorly
• Inferior articular facets face
anteriorly
7. MOB TCD
Articular Facets
• There are concave facets on the
transverse processes of the upper six
thoracic vertebrae, to articulate with
the tubercle of the upper ribs (pump
handle action)
• Flat facets on the transverse processes
of the lower vertebrae take part in the
pump handle action of the diaphragm
on the lower rib
8. MOB TCD
Thoracic Vertebrae
• Lower thoracic have larger
spines which are more
horizontal
• Laminae are broad and
downward projecting spines
overlap each or like the
slates on a roof
9. MOB TCD
First Thoracic Vertebrae
• Complete facet on the upper
and a demi-facet on the
lower portion of body
• Concave facet on transverse
process
• Superior surface resembles
a cervical vertebrae and has
projecting lips at the lateral
margin, the uncinate process
10. MOB TCD
Intervertebral Foramina
• Posterolateral to the vertebral
bodies and transmit spinal
nerves and vessels
• Formed by intervertebral
discs
• Adjacent vertebral bodies
• The grooved surfaces of
adjacent pedicles
• The lamina and attached
ligaments of vertebral column
11. MOB TCD
Thoracic Vertebrae
• Rotation takes place at the
facet joints
• Thoracic spinal canal is
circular and narrowest from
T4 – T9
• Corresponds to the portion of
the spinal cord with the
poorest blood supply
12. MOB TCD
Movements Thoracic Vertebrae
• Thoracic spine has greatest
rotation
• Least ROM overall, is relatively
stable, due to overlapping
spinous processes
• Thinner intervertebral discs
• Attachment of ribs to the sternum
• Flexion
• Extension
• Lateral flexion
• Rotation
13. MOB TCD
Thoraco-Lumbar Junction
• A transitional vertebra has
thoracic superior articular facets
and lumbar inferior facets
• On extension, the lower facets
of the transitional vertebrae lock
into the uppermost lumbar
vertebrae
14. MOB TCD
Facet Tropism
• The lumbar facets vary from the
sagittal disposition at the first and
second to almost coronal in the lower
• Facet tropism is when the facet on
one side is in the sagittal plane and
the other is in the coronal plane,
which adds to rotational stress
• Facet tropism, one inferior facet is
thoracic, the other lumbar
15. MOB TCD
Thoraco-Lumbar Junction
• Flexion is possible at this junction
• Extension is minimal
• You cannot mobilise this junction in
extension
• If you try, it is very painful
• You must mobilise it in flexion
16. MOB TCD
Thoraco-Lumbar Junction
• This change may occur in the lower
thoracic vertebrae
• The thoraco-lumbar junction is the
most exposed to injury, which may
occur at T10–11 or T12–L1
17. MOB TCD
Vertebral Joints
• Secondary cartilaginous
joints between the bodies
• Synovial plane between the
facets
18. MOB TCD
Intervertebral Discs
• Annulus fibrosis
• Concentric lamina run
obliquely
• Type I collagen at periphery
• Type II near nucleus
• Weakest portion is the
posterolateral and posterior
• Periphery has a nerve supply
• Thinner in thoracic region
19. MOB TCD
Nucleus Pulposus
• Gelatinous, hydrophilic,
proteoglycan gel in
• Collagen matrix
• Lies posterior in disc
• Nutrition = diffusion
• Compression force greatest
posterior
• May be due end plate fracture
21. Anterior and Posterior
Longitudinal Ligament
• Anterior longitudinal
ligament is attached
mainly to body of the
vertebrae
• Prevents
hyperextension
• Posterior is saw-toothed
• Attached mainly to the
intervertebral disc
• Prevents hyperflexion
MOB TCD
22. MOB TCD
Ligamentum Flava
• Joins the lamina and
extends to the capsule of the
facet joint
• Forms the posterior
boundary of the
intervertebral foramen
• It is highly elastic
• Helps to restrict hyperflexion
• The ligamentum flava is
thicker in the lumbar region
23. MOB TCD
Intervertebral Ligaments
• Interspinous ligament lies between
the spines
• The strong supraspinous ligament
joins the tips of the spine
• The inter-transverse ligaments join
the transverse processes and are thin
and membranous in the lumbar
region
24. MOB TCD
Facet Joints
• L1, L2 facets in sagittal
plane
• Lower in coronal
• Synovial plane
• Capsule attached to margins
• Meniscoid structures
25. MOB TCD
Facet Joints
• Narrowing of disc space
results in stress on facet joint
• Rotation
• Highest pressure
• Combined
• Extension
• Compression
27. MOB TCD
Facet Joint Syndrome
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Extension and rotation
Pain rising from flexion
Lateral shift in extension
Point tenderness over facet
Referred leg pain
32. MOB TCD
Scheuermann’s Disease
• Most common cause of pain in
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thoracic spine in adolescents
Anterior wedging of vertebrae
Thoracic kyphosis
Schmorl’s nodes within
endplate
Presents often during the last
2-3 years skeletal growth
Functionally, the vertebral end-plate displays characteristics of a trampoline, with the sub-end-plate trabecular bone acting as springs to sustain and dissipate axial load.
Despite the thinness of the vertebral end-plate, the hydraulic nature of marrow and blood vessels within the vertebral body, act to dampen axial loads, unless the local point pressure is too high. End-plate lesions can be induced experimentally before a disc will prolapse through the anulus, suggesting a protective mechanism over anular injury and potentially cord or root compression.
Excessive loads may result in perforation of the end-plate, usually in the region of the nucleus and often in the path of the developmental notchord.
As can be seen on the left, the vertebral end-plate is a tenuous cartilaginous membrane which from direct measurement is approximately 0.5mm thick, connected to trabecular bone within the cortical shell.
Lesions of the end-plate arising from sporting activities are reported to be frequent. Typical aetiology involves dynamic compressive axial loads, common in landing sports: eg: gymnastics
Discal material is extruded through the end-plate into the vertebral body. At the time of injury, the lesion may be painful due to the inflammatory response to the lesion. It has been postulated that such injury predisposes the disc to early degenerative change [Roberts et al, 1997 European Spine Journal 6: 387]
The late stage of healing involves sclerosis of bone around the site of injury, demonstrated on the right [arrow] form a CT at T11-12
The notochordal streak, as depicted by Schmorl & Junghanns from their classic text, showing a foetal specimen [left] and the progressive apoptosis of these cells during maturation and differentiation of the disc and vertebral body.
Typically, Schmorl’s nodes occur close to this site, suggesting both a functional and genetic predisposition to compressive load failure of the end-plates in some individuals.
The incidence of end-plate lesions in sport participants varies, however, these may result from pre-existing anatomical abnormalities.
In the case of Scheuermann’s disease, there can be multiple end-plate lesions over many segments.
According to Sorenson, the characteristics of this disease involve four or more segments with lesions of the end-plates, and corresponding vertebral wedging.
Accentuated kyphosis and a painful thoraolumbar spine are the main clinical features.
In a recent cadaver based study, discs of the thoracic spine were examined for degenerative changes. Those within the middle and lower regions, which appear suited for axial rotation, showed the highest degeneration.
A coincidental finding were small disc protrusions at multiple thoracic levels contained within the posterior longitudinal ligament.
[arrow].
A response to discal injury involving the peripheral anulus is the formation of osteophytic lipping.
It can be seen that spinal joints that enjoy the greatest ranges of rotation are disposed to greatest discal degeneration. This concept applies equally to the cervical, thoracic and lumbar regions.
The spine responds differently to stress from:
Axial compression and tension
Torsion
Hyper-mobility
Over-use and excessive training
In the case of disc injury, the tendency for shear stress to result may contribute to the syndrome of ‘segmental instability’ described by Panjabi as an increased loss of control in the neutral zone of segmental motion.