Anatomy And Biomechanics Flashcards
Lordosis of the lumbar spine develops with walking and is fully developed by _____ years of age
8-10
Describe the shape of the lumbar vertebral body.
- Kidney shaped
- Wider than deep
- Increase in size from above down
- Form a lordotic curve
The disc height to body ratio in the lumbar spine is _____
1:3
The approximate height of vertebrae in the lumbar spine is ______
9mm
What is the major role of the IVDs in the lumbar spine
Major role is not in directing movement, but in absorbing and dispersing compressive loads.
In what plane are the articular facet surface of the lumbar spine?
Sagittal, with lumbosacral becoming more coronal
The inferior articular facets are _____ and mate with the superior articular facets that are ______.
convex: concave
The inferior facet lies _______ (outside/inside) the superior facet.
inside
The lumbar facets resist what kind of motion
Rotation (less so in L5-S1)
The lumbosacral facets are the most common sight for ____ _____.
facetal tropism
What percentage of axial load to the facets in the lumbar spine normally carry? What percentage do they carry in the hyper extended posture?
Facets normally carry 18% of axial load and up to 33% in hyper extended postures.
The facets with their articular capsules provide up to ____% of the torsional strength of the lumbar spine.
45
Why are mammillary bodies used as adjustive contacts in the lumbar spine?
Because the TPs are small and run obliquely posterolateral such that their contact can be uncomfortable
TPs are located up ____ interspinous spaces?
1
Describe the SPs in the lumbar spine?
- Run almost directly horizontal to the vertebral body.
- Large and hatchet shaped.
- The L5 SP is shorter, more rounded and difficult to distinguish.
- can create a bony block for extension
- superficial and sensitive to firm pressure
What is the GROM for flexion of the lumbar spine?
40-60 degrees
What is the GROM for extension of the lumbar spine?
25-30 degrees
Flexion/extension is the greatest range of motion in the lumbar spine, flexion more than extension. _____% of trunk flexion occurs in the lumbar
spine.
75
What is the SROM for flexion/extension of the lumbar spine?
average of 14 degrees of combined movement per segment
12 degrees at L1-L2 and increasing to 17 degrees at L5-S1
During flexion/extension of the lumbar spine, the IVD _____ posteriorly during flexion and _____ during extension
opens: approximates
During flexion and extension of the lumbar spine, the disc bulges on the ____ side and
retracts on the ____ side.
concave: convex
In the lumbar spine, the articular facets _____ during flexion and ______ during extension.
Separate: approximate
In the lumbar spine, sagittal plane rotation is coupled with what movement
Sagittal plane translation
At what amount of translation is a motion segment in the lumbar spine considered clinically unstable?
Greater than 4.5mm
What is the GROM for rotation in the lumbar spine?
5°-18° to each side.
What is the SROM in the lumbar spine?
Minimal an uniform at 2°-3° combined movement per segment
During rotation of the lumbar spine, the facet joints ____ on the side of rotation and _____ on the side opposite rotation.
separate (gap): approximate
- The facet joints act as a significant barrier to rotational
mobility in the lumbar spine.
What is the GROM for lateral flexion of the lumbar spine?
15-25 degrees
What is the SROM for lateral flexion of the lumbar spine?
approximately 6° per side with movement dropping off to approximately 3° at L5-S1.
During lateral flexion of the lumbar spine, the IVD opens on the _____ side and closes on the ______.
contralateral: ipsilateral
During lateral flexion of the lumbar spine, the disc bulges on the _____
side and retracts on the _____ side
concave: convex
During lateral flexion of the lumbar spine, the articular facets glide apart on the ______ side and approximate on the ______ side.
contralateral: ipsilateral
Why do we use coupled movements in lumbar manipulative setups?
- lateral flexion limits the amount of rotation induced with side posture adjustments
- coupling motion helps in the localization of pre-adjustive tension.
