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Vertebral Column. Osteology. 7 C, 12 T, 5 L, 5 S (Fused as Sacrum), 4 coccygeal Primary Curves Secondary Curves Anterior/Posterior alignment. Primary Curve. Vertebral Segments. A-P View. Secondary Curves Lateral. Vertebral Column. Osteology. Typical Vertebrae Body
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Osteology • 7 C, 12 T, 5 L, 5 S (Fused as Sacrum), 4 coccygeal • Primary Curves • Secondary Curves • Anterior/Posterior alignment
Osteology • Typical Vertebrae • Body • Superior and inferior surfaces of body (plateaus) • Thickened around the rim, location of epiphyseal plates • Cartilaginous end-plates • Vertebral Arch • Pedicles, Laminae • Transverse Processes • Spinous Process • Facets – superior articular and inferior articular • Spinal Foramen • Intervertebral Foramen
Arthrology • Intervertebral Discs • Fibrocartilaginous joints • Increase in size from C to L (3mm to 9 mm) • Ratio remains the same • Make up 20-30% of length of column
Arthrology • Two Components • Outer rim of fibrocartilage called the anulus fibrosus (attaches to cartilaginous end plate) • Connects vertebral bodies in a fibrocartilaginous joint (no capsule, little motion)
Arthrology • Anulus encloses a central mass called the nucleus pulposus • About 80-90% water, less with increased age • Contains a mucopolysaccharide matrix • Changes shape, releases and absorbs water. Thicker in AM than PM • Neither blood vessels or nerves penetrate nucleus
Arthrology • Structure deforms when pressure is put on vertebral column as in weight bearing • Acts as a shock absorber • Annulus totally encloses the nucleus and keeps it under constant pressure • As you get older, the H2O content decreases and the nucleus becomes more fibrocartilaginous, therefore less easily deformable and more easily damaged
Arthrology • Nucleus, when under extreme pressure, can herniate or extrude from the disc in a posterior or posterior-lateral direction • Usually occurs in cervical or lumbar region • Nucleus can put pressure on spinal nerve causing refereed symptoms (motor and sensory) • Can cause pressure on cord itself if true posterior
Arthrology • Facet Joints (Typical) • Superior articular facets of one vertebrae with inferior facets of vertebrae above • Synovial gliding joints • Surrounded by joint capsule and small capsular ligaments • The type and amount of motion in any given part of the spine is dictated by the orientation of the articular facets as well as the fluidity, elasticity and thickness of the intervertebral discs
Arthrology • Typical movements in sections of the spine • Lumbar • Thoracic • Cervical
Major Ligaments of the Spine • Anterior Longitudinal Ligament • Dense band along anterior and lateral surface of the vertebral bodies from C2 to sacrum • Superficial - bridge several vertebrae • Deep – short, run from V to V, blends with fibers of anulus fibrosus • Limits extension of V column • From C1 to skull, called Atlanto-Occipital Membrane
Major Ligaments • Posterior Longitudinal Ligament • Runs along posterior surface of vertebral bodies (anterior to spinal canal) • C2 to Sacrum • Short fibers attach ligament to posterior disc, reinforce disc posteriorly • Superiorly, continues to occiput, called Tectorial Membrane • Limits flexion
Ligaments • Supraspinous • Spinous process to spinous process – tip to tip • C7 to sacrum • Limits flexion • In cervical region, becomes much thicker with a greater elastic content • Called Ligamentum Nuchae
Ligaments • Interspinous • Found between spinous processes • Most well developed in lumbar region • support
Ligaments • Ligamentum Flavum • Connects lamina of one to lamina of the other • Found from axis to sacrum • Limit flexion • Continuation to the skull is called Posterior Atlanto-Occipital membrane
Ligaments • Intertransverse • Only well-developed in Lumbar Region • Between transverse processes • Limit lateral flexion
Special Joints of Spine • Lumbo-Sacral • L5 and S1 (or sacrum) • Drastic change from lordotic to kyphotic curve • Strong “shearing forces” • The sacral segment is inclined anteriorly and inferiorly forms an angel with the horizontal called the lumbo-sacral angle • Angle can be increased significantly with an increase in lumbar curve • During flexion/extension the greatest mobility of the spine occurs between L5 and S1
L5/S1 • Spondylolysis – a developmental anomaly of the lamina wherin a bony defect separates the sup. and inf. Articular processes thus separating the post. Part of the neural arch from the ant. Arch and the vertebral body • Usually asymptomatic, very common in males