Lumbar Spine Flashcards
What is the most important characteristic of the lumbar spine?
Bear tremendous loads created by body weight
What region of the spine is largely responsible for trunk mobility? ***
Lumbar spine
In which way to the inferior articular processes of the lumbar spine fact?
Anterolaterally (convex)
In which way to the superior articular processes of the lumbar spine fact?
Posteromedially (concave)
What is a tropism?
Developmental abnormality where one facet faces sagittally and the other faces faces coronally
Where does tropism usually occur in the lumbar spine?
Mostly L5-S1
Then L4-L5
Lumbar facets primarily lie in what plane?
Sagittal plane
When do facets become more coronal again after the lumbar spine?
Lumbosacral junction
The facet configuration of the lumbar spine limits what movement and allows for great mobility of what movements?
Limits rotational flexibility
Allows greater flexion/extension
The coronal facet orientation at L5-S1 limits what movement?
Posterior*/anterior shear (Z translation)
What effect does hyperlordosis have on weight-bearing load of the lumbars?
Increases it
What is the primary movement of the lumbar spine?
Flexion/extension (θX)
Which occurs more in the lumbar spine: extension or flexion?
Flexion (2X)
Why is axial rotation limited in the lumbar spine?
Sagittal facet orientation
During lateral bending accompanied with axial rotation in the lumbar spine, to which direction does the spinous move?
Ipsilateral side (same)
Why does the spinous move to the ipsilateral side in the lumbar spine during lateral bending coupled with axial rotation?
Eccentric lengthening of the quadratus lumborum
In what area of the lumbar spine can the spinous sometimes switch and rotate to the contralateral side during lateral bending coupled with axial rotation?
L4 and L5
What is the location of the nucleus pulposus in the lumbar spine?
Posterior
What is the IVD height to vertebral body height ratio in the lumbar spine?
1:3 (middle compared to cervicals and thoracics)
What is the purpose of the IVD height to body ratio of the lumbars being in the middle compared to cervicals and thoracics?
More movement than thoracics, less then cervicals
Greater resistance to axial compressive forces
What does the lumbar spinal canal protect proximally?
Conus medullaris (enlargement of the spinal cord)
What does the lumbar spinal canal protect distally?
Cauda equina (spinal nerves)
What tethers the CNS to the coccyx?
Filum terminale
At what vertebral level does the spinal cord end?
L2
After the spinal cord ends at L2, what do the nerve roots continue as?
Cauda equina
What structures are responsible for defining the range of motion and stabilizing the dural sac withing the foraminal canal?
Hoffman ligaments
Although its movements are limited, how is the spinal cord able to demonstrate flexibility during different movements and activities?
Elastic deformation
When does the lumbar curve start to develop?
About 9-12 months of age (as one begins to sit up)
Where is the apex of the lumbar curve?
L3-4 disc
When does the lumbar curve become established in nature?
About 18 months (as one begins to stand)
What is the normal lumbar curve angle?
20-60 degrees
What type of curve is the lumbar curve?
Secondary lordotic
What are the effects on the sacral base angle with an anterior pelvic tilt? On the lumbar lordosis? Facets?
Increased sacral base angle
Increased lumbar lordosis
More weight bearing responsible on facets
What are the effects on the sacral base angle with an posterior pelvic tilt? On the lumbar lordosis? Disc?
Decreased sacral base angle
Decreased lumbar lordosis
More weight bearing responsibility on disc
A posterior pelvic tilt decreases the spine’s ability to absorb what kind of forces?
Axial compression
What is the major stabilizer of the lumbar spine?
Quadratus lumborum
The quadratus lumborum is always active during what motions?
Flexion, extension, lateral bending
What do the ALL and PLL attach to?
Vertebral body and annulus
What movements are restriction by the ALL and PLL?
ALL - extension
PLL - flexion
What ligament is highly elastic and acts as a barrier to material that would otherwise encroach on the cord during range of motion?
Ligamentum flavum
The lumbodorsal fascia is an attachment site for what muscles?
1 Transverse abdominis
2 Internal oblique
3 Latissimus dorsi
The lumbodorsal fascia as as what kind of structure to constrain long tendons of thoracic and lumbar extensors?
Large extensor retinaculum
