Flashcards in Exam 2 Lumbopelvic Deck (50)
What is the most important characteristic of the lumbar spine?
it must bear tremendous loads created by body weight, lifting, and muscle actions
In addition to bearing heavy loads, what other responsibility does the lumbar spine have that places significant biomechanical demand on this region?
T/F: the inferior articular processes of the L/S are concave and face anterolaterally.
Describe the superior articular processes of the L/S.
concave and face posteromedially
What plane do the lumbar facets lie in primarily?
the sagittal plane
What motion is limited in the L/S? increased?
Which facets of the L/S have a coronal orientation rather than sagittal? What motion does this limit?
limits posterior/anterior shear (Z translation)
T/F: the lumbar facets normally carry 18% of the axial load and up to 33% in extension.
Which region of the L/S has the greatest combined flexion/extension? Least?
Which region of the L/S has the greatest range of lateral bending (ThetaZ)? Least?
Which region of the L/S has the greatest one side axial rotation (Theta Y)? Least?
L1-L5 all have relatively equal axial rotation;
L5-S1 has the least axial rotation
What motions are coupled in the L/S? What does this mean for spinous?
lateral bending is coupled with axial rotation;
spinous to ipsilateral side
Is the nucleus of the IVD in the L/S more anterior, posterior, or in the middle?
What is the disc height-to-body height ratio in the L/S?
1:3; greatest resistance to axial compressive forces
What is the name for the enlargement of the spinal cord that is protected by the L/S? What other main structure is protected by the L/S distal to the lumbar enlargement of the spinal cord?
What bone is the CNS tethered to via the filum terminale?
Where does the spinal cord end? What do the nerve roots continue down the spinal canal as?
T/F: Nerve roots exit the dura of lumbar spinal canal slightly below the foraminal openings to provide "slack" which prevents stretching of the nerve roots.
False; NRs exit the dura slightly above the foraminal openin, causing therir course to be more oblique and their length to increase
T/F: The Lordotic curve of the L/S is considered a primary curve.
False; secondary curve
Where is the apex of the Lumbar curve?
What range (in degrees) should the lumbar curve measure?
T/F: An increase in the sacral base angle will result in more weight bearing responsibility on the facets.
True; increasing the sacral base angel with an anterior pelvic tilt results in an increase in the lumbar lordosis which places more weight on the facets.
T/F: An increase in the sacral base angle will result in more weight bearing responsibility on the disc which will decrease the spine's ability to absorb the axial compression forces.
False; A decrease in the sacral base angle will do this as it decreases the lumbar lordosis
What muscle is the major stabilizer of the L/S?
What motions are restricted in by the ALL and PLL? Which is more well developed?
Restrict excessive flexion/extension;
T/F: The lumbodorsal fascia acts like a large flexor retinaculum to constrain long tendons of thoracic and lumbar muscles.
False; acts as a large extensor retinaculum constraining thoracic and lumbar extensors
What ligament of the L/S guards against posterior shear, assists facet joints to remain in contact/gliding with rotation, and acts like a collateral ligament controlling vertebral rotation to follow an arc through flexion range?
What motion does the supraspinous ligament provide resistance against?
excessive forward flexion
T/F: The facet capsule is well developed in the L/S, restricting joint flexion and distraction of facet surfaces during axial rotation.