List the 2 primary curves and the 2 secondary curves
2 primary - kyphotic
2 secondary - lordotic
How do the secondary curves develop?
developed as we grow (tummy time) then continue to develop as we develop to crawling and sitting
What is the advantage of a curved vertebral column as opposed to a straight rod?
Define what the motion segment is
- consists of any 2 adjacent vertebrae, intervertebral disc, and soft tissue that secures them
Describe what happens in a bilateral fracture at the pars interarticularis. Where is this most likely to occur in the spine and why?
What transmits tension and bending forces from posterior elements to vertebral body?
pedicles
What is the portion of laminae between superior and inferior articular processes? What stress is it subject to?
- subject to bending forces
What forms the articular pillar?
articular processes AKA zygapophyseal joint
What is the function of lamina?
transmit forces from the articular, transverse and spinous processes to the pedicles
What determines size of intervertebral discs?
amount of motion and magnitude of the load that is being transmitted
How is available motion determined in intervertebral disc? Where is motion the greatest-least?
What activities and body positions place the most amount of pressure on the intervertebral discs? How can you use this information when educating patients on lifting mechanics?
What 2 factors affect available motion of articular process and facets?
shape and orientation
What is the function of anterior longitudinal ligament?
- reinforce anterolateral portion of anulus fibrosus and anterior aspect of intervertebral joints
What is the function of posterior longitudinal ligament?
What is the function of ligamentum flavum?
limits forward flexion, particularly in lumbar
What is the function of interspinous ligaments?
limits forward flexion
what is the function of supraspinous ligaments?
limits forward flexion
What is the function of intertransverse ligaments?
limits contralateral lateral flexion
What is the function of facet joint capsules?
limits motion and adds stability
describe joint coupling
association of one motion around an axis with another motion around another axis
ex: lateral flexion and rotation
Coupling patterns vary based on what?
what part of motion segment determines magnitude of movement?
interbody joints - distributes load and creates space for movement and passage of the spinal nerve roots
what part of motion segment determines direction of movement?
facet joints - “train tracts” that are influenced by geometry, height, and spinal orientation