Lumbar biomechanics Flashcards
what is the shape of the lumbar pedicles and laminae?
short broad and strong
What is the shape of the spinous processes of lumbar vertebrae?
thick and broad
what is the shape of the lumbar transverse processes?
long slender and flattened on the anterior and posterior survaces.
what is the feature on the superior articular processes?
mamillary process, I think its used as landmark in manipulation.
What direction are the lumbar fascets facing?
they are in the saggital plane mostly so they face medailly and laterally.
degrees of the lumbar fascets?
45 degrees from the frontal plane and 90degrees from transverse
What is the degree of the lordodic curve?
20-60 degrees with and average of 35. from L1 to sacrum
Where is the apex of the lordodic curve?
L3-L4 is the apex
what causes lordodic secondary curve to form?
it happens in response to standing.
what tilt increases or decreases lordosis?
Antior pelvic tilt decreases, posterior pelvic tilt increases lordosis.
Where is the nucleus pulposis located in lumbar disk?
it is posterior in the disk, similar to cervical, while thoracic is centered
what does huge lumbar disk help resist?
axial compression forces
what inhibits ratial expansion of nucleus pulposus?
the increased tension of the annular fibrosis.
if annulus doesn’t expand with increased hydrostateic pressure what does it do?
increase pressure up and down twoard the end plates.
what is a disk bulge?
shallow generalized extension of the disc tissues beyond the edges of the vertebral gody
is a disc bulge a herniation?
No
what may a disc bulge cause?
compression of neural tissues, pain and joint disfunction
In what directions can disk bulge?
Symmetrically, asymetrically twort one side,
Is shape of disc in bulge diagnostic?
no
where is assymetrical bulging of the disk margin often found?
in severe scoliosis
what is a herniation?
When disk fibers rupture through the annular fibers.
What can disc herniation cause?
compress Nerve, pain, inflammation,
what is concidered a localized herniation?
involves less than 50% of the disc circumference.
What is a focal herniation?
involves less than 25% of the disc circumference
What is a broad base herniation?
involves between 25 and 50% of disc circumference.
what are the two forms of herniated disc?
protrusion or extrusion
What is a protrusion shaped herniation?
base of herniation is broader than the distance is protrudes into spinal canal. So broad
What is a extrusion shaped herniation?
disc balloons into canal with a narrow base, may end up sequestered.
what directions can annular tears form?
radial - transvers or concentric
what can annular tears do to disc?
weaken, pain in outer 1/3 and disk material may get into tears.
what is the compined lumbar segment flexion and extension?
15 degrees
what are the combined movements of lumbar flex/extend?
saggital plane rotation and translation.
in flexion of lumbar what happens to vertebrae and fascets.
vertebra, foreward tilt and slide, facets- slide up
in extension of lumbar what happens to vertebrae and facets?
vertebra - tilt back, Fascet- approximate - squish together
what is the averge lumbar lateral flexion?
6 degrees to each side although the lumbar sacral only has 3 degrees
what happens to lumbar facets in lateral flex?
in right lat flex, right facets glide close, left facets glide apart.
what is the coupled rotation of lumbar lateral flexion?
lat flexion with opposite side rotation, so flex left will rotate right, opposice of cervical and upper thorsic
why is lumbar roatation so limited?
the saggital fascets limit it to 2 degrees each side.
what is the coupled rotation of lumbar rotation?
rotation with lateral flesion and slight saggitaal plane rotation.
specifically what is the difference between upper and lower lumbar rotation?
Upper lumbar rotation has opposite side lateral flesion, lower lumbar rotation L4-L5 is coupled with same side lateral flexion.
