Lecture 4: Vertebral Column 1 Flashcards
What are the curvatures of the vertebral column and what is their purpose?
1˚ curve: thoracic and sacral
2˚ curve: cervical and lumbar
increase shock absorbing resilience
What are some examples of abnormal curvatures of the vertebral column?
excessive thoracic kyphosis: exaggerated thoracic curvature
excessive lumbar lordosis: exaggeration of lumbar curve
scoliosis: abnormal lateral curvature with rotational deformity of vertebrae
What is a motion segment?
a functional unit of the vertebral column which comprises of two adjacent vertebrae and the associated soft tissues
What are the joints contained by each motion segment?
intervertebral disc (symphysis) between vertebral bodies right and left zygapophyseal joints (synovial plane multiaxial) between superior and inferior articular processes
How much ROM do motion segments provide?
permit small segmental ROM but large total ROM
- > flexion/extension
- > lateral flexion
- > rotation
What are the regional characteristics of vertebrae?
body shape and size, vertebral foramen shape and size, transverse process, spinous process, articular processes (zygapophyseal joints)
What is spondylolysis?
fracture of the pars interarticularis (region between superior and inferior articular facets)
weakest portion of neural/vertebral arch
congenital or mechanical
What is spondylolisthesis?
complete bilateral fracture of pars interarticularis = anterior slippage of vertebra with respect to vertebra below it (90% occur lumbosacral joint L5/S1)
What is the effect of aging of vertebrae?
bone density and strength decreases from the 4th decade (spondylosis)
osteophytes (bony spurs) can develop due to changes in bone shape with age due to altered mechanical stresses on joints
osteoporosis is not a normal part of aging
resistance exercise increases bone strength through mechanical loading
What is the hyaline cartilaginous end plate and what does it do?
transmits weight to adjacent vertebral body
confines nucleus pulposus and annulus fibrosus
helps provide nutrition to IV disc
What is the annulus fibrosus and what does it do?
thick, outer fibrocartilaginous alternating rings
holds the vertebral bodies together
What is the nucleus pulposus and what does it do?
central gelatinous substance with high fluid content
keep vertebral bodies apart, permitting them to roll over one another to allow frictionless movement
shock absorbing capabilities
What are features of the IV disc?
largely avascular -> discs rely on body movement to pump nutrients in and waste products out via diffusion
innervation -> outer 1/3 annulus fibrosus innervated in healthy, young people
account for 25-33% of vertebral column length
What does the annulus act as?
annulus acts as a coiled spring whose tension holds the vertebral bodies together against the resistance of the nucleus pulposus
What does the nucleus pulposus act as?
acts like a ball bearing composed on incompressible gel that the vertebrae roll over during flexion/extension/lateral bending and rotation while the facet joints guide these movements