Download - Anatomy of thoraco lumbar vertabrae ()
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Professor Emeritus Moira O’Brien
FRCPI, FFSEM, FFSEM (UK), FTCD
Trinity College
Dublin
Thoracic and Lumbar Vertebrae
Vertebrae
• 7 Cervical• 12 Thoracic• 5 Lumbar• Sacrum
Curvatures• Cervical• Thoracic• Lumbar
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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
Typical Vertebrae MOB TCD
• 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
Typical Thoracic Vertebrae MOB TCD
• 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
Typical Thoracic Vertebrae 2-9 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
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• 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
Thoracic Vertebrae MOB TCD
• 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
First Thoracic Vertebrae 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
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• 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
Thoracic Vertebrae MOB TCD
• 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
Movements Thoracic Vertebrae 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
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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
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• 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
Thoraco-Lumbar Junction MOB TCD
• 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
Thoraco-Lumbar Junction MOB TCD
Vertebral Joints
• Secondary cartilaginous joints between the bodies
• Synovial plane between the facets
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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
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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
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End-Plate Mechanics MOB TCD
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
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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
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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
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Facet Joints
• L1, L2 facets in sagittal plane
• Lower in coronal• Synovial plane• Capsule attached to margins• Meniscoid structures
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• Narrowing of disc space results in stress on facet joint
• Rotation• Highest pressure• Combined • Extension• Compression
Facet Joints MOB TCD
Facet Joints MOB TCD
• Extension and rotation• Pain rising from flexion• Lateral shift in extension• Point tenderness over facet• Referred leg pain
Facet Joint Syndrome MOB TCD
Blood Supply
• Lumbar arteries• Internal venous plexuses• External venous plexuses• Basivertebral veins• Valveless
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Nerve Supply
• Nerve supply • Peripheral annulus• Facet joint• Nerve = medial branch dorsal
ramus
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Axial Load and End-Plates MOB TCD
End-Plate Susceptibility
Schmorl & Junghanns, 1965, The Human Spine in Health and Disease
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Scheuermann’s Disease
• Most common cause of pain in 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
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Greene et al, 1985, J Pediatric Orthopedics 5:1
Scheuermann’s Disease MOB TCD
Young Athlete
• Scheuermann• Spina bifida occulta• In five junior rugby team
15 years• Scrum half• Degenerative facet joint
changes
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Scoliosis
• Congenital• Wedge or hemivertebrae due
to failure of segmentation leads to scoliosis
• Acquired• Racquet sports• Fencing• Sweep rowing• Javelin• Freestyle unilateral breathing
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Cancellous Bone
• Cancellous bone• 50% compressive
strength• Facet joints • 20% in standing
upright position
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Torsion and Disc
T12
T11
T10
T9
T8
T7
T6
T5
T4
T3
T2
T1
Giles & Singer, 2000, Clinical Anatomy and Management of Thoracic Spine Pain
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Spine Segment Movement
Giles & Singer, 2000, Clinical Anatomy of and Management of Thoracic Spine Pain
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