Lumbar Spine Flashcards
what is unique about the structures of hte lumbar spine?
large vertebral foramen and bodies
L5 transitional vertebra is larger in which direction?
anteriorly
what movements dot he lumbar spine favor and not favor as much?
favors flexion/extension
less lateral flexion and rotation
Size of vertebral foramen by extension by what percentage? what can this eventually lead to if excessive extension?
10%, nerve compression
coupled motion in flexion
rotation and lateral flexion to the same side
which vertebra has the largest amount of flexion and rotation? (where is the curve the largest when flexing forward?)
L2, L3
what degree are the collagen fibers oriented at and what direction is it in?
120 degrees, opposite direction
Describe IV disc hydration.
throughout the day, compressive loads cause loss of fluid. at night, reloading of fluid occurs.
in flexion, which direction does the disc move?
posterior
in rotation, what direction is the disc moving?
not rotating, just putting stress on the annulus
increase angle –> increase lordosis –> increase _____
shear
when do you have greater shear forces?
lumbosacral angle greater than 45 degrees
Normally, we have more compression
which muscles cause SOME posterior shear and MOSTLY compression?
deep erector spinae
why is the superficial erector spinae group considered a prime mover?
longer lever arm
what is causing tension at the throacolumbar fascia?
transversus abdominis, hip extensors applying tension on spinous processes, glut mac & contralateral lats,
Name the muscles of the anterior hoop.
rectus & transverse abs, external and internal obliques
which muscle controls the sacroiliac joint?
transversus abdominis
in lumbar extension, what happens at the pelvis?
posterior pelvic tilt
how much compression occurs at the lumbar interbody joints? how much on the facets?
80%, 20%
what specific structures limit anterior shear?
facets
how do the multifidi muscles act?
acts on individual segments
what is the action of quadratus lumborum?
ipsilateral flexion, contralateral eccentric control
what does the iliolumbar ligament prevent?
anterior sheer
when is the iliolumbar ligament loaded?
in flexion
what motion do the iliolumbar ligaments resist?
movment of L5 on S1
what occurs to the lumbar spine when bending forward?
tension on the posterior ligaments, anterior shear on the upper vertebral body, compression on the anterior disc
how to increase the stability of the lumbar spine. (3)
- use co-contraction of flexors and extensors
- increase intra-abdominal pressure
- have sufficient stability; too much can cause joint compression
what has more pressure on IV disk: sitting unsupported or standing?
sitting unsupported
Sitting unsupported is the same pressure as ______
coughing
lifting 100N causes greater/less force than holding 50N at arms length
less force
