Anatomy of thoraco lumbar vertabrae (www.Am-medicine.com)
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Anatomy of thoraco lumbar vertabrae (www.Am-medicine.com)

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  • Cover slide <br />
  • 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. <br /> 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. <br /> 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. <br />
  • 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. <br /> 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 <br /> 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] <br /> 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 <br />
  • 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. <br /> 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. <br />
  • The incidence of end-plate lesions in sport participants varies, however, these may result from pre-existing anatomical abnormalities. <br /> In the case of Scheuermann’s disease, there can be multiple end-plate lesions over many segments. <br /> According to Sorenson, the characteristics of this disease involve four or more segments with lesions of the end-plates, and corresponding vertebral wedging. <br /> Accentuated kyphosis and a painful thoraolumbar spine are the main clinical features. <br />
  • 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. <br /> A coincidental finding were small disc protrusions at multiple thoracic levels contained within the posterior longitudinal ligament. <br /> [arrow]. <br /> A response to discal injury involving the peripheral anulus is the formation of osteophytic lipping. <br /> 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. <br />
  • The spine responds differently to stress from: <br /> Axial compression and tension <br /> Torsion <br /> Hyper-mobility <br /> Over-use and excessive training <br /> 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. <br />
  • Copyright slide <br />

Anatomy of thoraco lumbar vertabrae (www.Am-medicine.com) Anatomy of thoraco lumbar vertabrae (www.Am-medicine.com) Presentation Transcript

  • MOB TCD Thoracic and Lumbar Vertebrae Professor Emeritus Moira O’Brien FRCPI, FFSEM, FFSEM (UK), FTCD Trinity College Dublin
  • MOB TCD Vertebrae • • • • 7 Cervical 12 Thoracic 5 Lumbar Sacrum Curvatures • Cervical • Thoracic • Lumbar
  • MOB TCD Typical Vertebrae • • • • • Basic parts Body Neural arch consists of Pedicles Lamina fuse posteriorly to form spine • Transverse processes arise from pedicles • Superior and inferior articular processes
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • 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
  • MOB TCD Vertebral Joints • Secondary cartilaginous joints between the bodies • Synovial plane between the facets
  • 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
  • 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
  • MOB TCD End-Plate Mechanics
  • 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
  • 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
  • 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
  • MOB TCD Facet Joints • L1, L2 facets in sagittal plane • Lower in coronal • Synovial plane • Capsule attached to margins • Meniscoid structures
  • MOB TCD Facet Joints • Narrowing of disc space results in stress on facet joint • Rotation • Highest pressure • Combined • Extension • Compression
  • MOB TCD Facet Joints
  • MOB TCD Facet Joint Syndrome • • • • • Extension and rotation Pain rising from flexion Lateral shift in extension Point tenderness over facet Referred leg pain
  • MOB TCD Blood Supply • • • • • Lumbar arteries Internal venous plexuses External venous plexuses Basivertebral veins Valveless
  • MOB TCD Nerve Supply • • • • Nerve supply Peripheral annulus Facet joint Nerve = medial branch dorsal ramus
  • MOB TCD Axial Load and End-Plates
  • MOB TCD End-Plate Susceptibility Schmorl & Junghanns, 1965, The Human Spine in Health and Disease
  • MOB TCD 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
  • MOB TCD Scheuermann’s Disease Greene et al, 1985, J Pediatric Orthopedics 5:1
  • MOB TCD Young Athlete • Scheuermann • Spina bifida occulta • In five junior rugby team 15 years • Scrum half • Degenerative facet joint changes
  • MOB TCD Scoliosis • Congenital • Wedge or hemivertebrae due to failure of segmentation leads to scoliosis • Acquired • Racquet sports • Fencing • Sweep rowing • Javelin • Freestyle unilateral breathing
  • MOB TCD Cancellous Bone • Cancellous bone • 50% compressive strength • Facet joints • 20% in standing upright position
  • MOB TCD Torsion and Disc T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 Giles & Singer, 2000, Clinical Anatomy and Management of Thoracic Spine Pain
  • MOB TCD Spine Segment Movement Giles & Singer, 2000, Clinical Anatomy of and Management of Thoracic Spine Pain
  • “BMJ Publishing Group Limited (“BMJ Group”) 2012. All rights reserved.”