Lumbar Spine Flashcards
Describe the Osteology of the Lumbar Spine:
Relate the structure to function:
- 66% lordosis L4-S1 (radiographic – 47-64 deg)
- Facets are 90 deg from transverse, 45 deg from frontal
- FSU – 2 vertebrae, IVD, and soft tissue structures
- Anterior – bodies, discs, ALL (compression)
- Posterior – SP, TP, facets, LF, PLL (guide motion)
- IVD – endplates, AF (fibrocartilage), NP (gelatin – GAG, H2O) – distributes load, etc
Interpret the influence of the spine structure on osteo- and arthrokinematics:
- Facet orientation (90 from trans; 45 from frontal)
- Flex/Ext – 12-20 per segment
- Rotation – 2 per segment (except L5-S1 has 6)
- Lat Flex – 6 per segment
- Limits on Flexion – posterior elements; on extension (anterior elements)
Compare and contrast lumbar spine with other spine regions:
- C1-C2 – lots of rotation – 40-45 deg (20 from trans), limited LF
- C3-C7 – 45 from frontal/45 from trans – F/E, LF, Rot – increases as you go down for flexion
- T1-T12 – 60 from trans, 20 from frontal – limited F/E, LF, some rotation
- L1-L5 – 90 from trans, 45 from frontal – increased F/E, some LF, limited Rotation
There is ______ extensor effort when Lordosis is maintained.
decreased
What is the gold standard for measuring Lumbar lordosis?
Radiographic Measurement
What is the gold standard for measuring Lumbar lordosis?
Radiographic Measurement
What are the typical ranges from measuring lumbar lordosis when Radiographically?
47 - 64 degrees
What are external ways to measure lumbar lordosis?
- bendable rules
- strain gauges embedded with tape
- inclinometers
- accelerometers
Describe external mesures validity when measuring lumbar lordosis?
all have poor concurrent validity when compared to radiograph
Describe external mesures validity when measuring lumbar lordosis?
all have poor concurrent validity when compared to radiograph
Describe how radiographic measurement is taken:
- line drawn parallel to superior Endplate of L1
- line drawn parallel to the endplate of L5
- Lines drawn Perpendicular to both L1 and L5 lines
- the angle between the intersection of the two perpendicular lines is the total lumbar lordosis angle
When speaking of spinal mechanics what is usually being spoken of?
The structures that make up the functional spinal unit
What does the Functional Spinal Unit consist of?
- 2 Adjacent Vertebral bodies
- Intervertebral Disc (IVD)
- Associated Soft Tissue
- is also called a “Motion Segment”
What elements does the Lumbar Vertebral Structure consist of
Anterior Elements: - 2 Vertebral bodies - IVD - Longitudinal Ligaments Posterior Elements: - Vertebral Arches - Spinous and Transverse Processes - Facet Joints - Posterior Ligaments
Posterior Elements of Lumbar vertebral Structure:
- Vertebral Arches
- Spinous and Transverse Processes
- Facet Joints
- Posterior Ligaments
Anterior Elements of the Lumbar vertebral structure:
- 2 Vertebral bodies
- IVD
- Longitudinal Ligaments
Anterior Elements of the Lumbar vertebral structure:
- 2 Vertebral bodies
- IVD
- Longitudinal Ligaments
Purpose of Anterior Elements of the Lumbar vertebral structure:
- bear compressive loads
- larger caudally (loading increases)
Purpose of Posterior Elements of the Lumbar vertebral structure:
- Guide Movement
- Motion determined by facet joint orientation
Where does loading increase in the lumbar spine and why?
increases caudally because the V. bodies get larger
What elements guide the movement of the lumbar vertebrae?
posterior elements
What determines the motion of the lumbar vertebrae?
the facet joint orientation
Lumbar facet joints:
- restrict motion (but also allow motion depending on orientation)
- serve as a site for muscle attachments
Lumbar Transvers Processes:
- muscle & ligament attachments
- increase moment arm by extending out laterally (better mechanical advantage)
Lumbar Spinous Processes:
similar to Transverse Processes:
- muscle & ligament attachments
- increase moment arm by offsetting attachment point from the axis of rotation
Another name for Facet Joint is a __________.
Z joint
Describe the articulation of a typical facet joint:
superior facet articulates with the inferior facet of the adjacent vertebrae
Describe the innervation of the facet joints:
- Highly Innervated!
- Full of Mechanoreceptor (for proprioception)
- also full of nociceptors (for pain)
Where does most of our sense of where our bodies are in space come from?
Facet Joint Mechanoreceptors
Describe the Joint Surface Orientation of the Lumbar facet joints:
- 90 degrees to Transverse plane
- 45 degrees to frontal plane
What do the lumbar facet orientations also?
- Flexion/Extension
- Lateral flexion
- Minimal Rotation
describe the lumbosacral facet joint:
- oblique orientation
- allows more rotation
What are the facet joints of lumbar spine important for?
What does it depend on
- load sharing with the IVD
- posture (contact between facets changes depending on posture position)
How much of total load is on facet joints during hyperextension?
30% of total load
What positions increase loading on facets?
- hyperextension
- flexion combined with rotation (don’t twist and bend!!)
Describe the purpose of the passive structures involved with lumbar spine:
Anterior longitudinal ligament:
- v. body attachment
- less attachment to the disc
-
Describe the purpose of the passive structures involved with lumbar spine:
Anterior longitudinal ligament: - v. body attachment - less attachment to the disc - tight in extension (limits extension) Posterior Longitudinal Ligament: - mainly Disc attachment - less attachment to body - tight in flexion (limits flexion) Ligamentum Flavum: - connects adjacent vertebral arches - High elastin content (means it is an active ligament) - because active, Contracts during extension, elongates during flexion - under constant tension -- pre-stresses the disc to create intradiscal pressure (important for: providing stability to the spine)
Name the components of the IVD:
- inferior/superior endplates
- annulus fibrosis (fibers that surround gel substance in center)
- nucleus pulposus
Name the 3 functions of the IVD:
- weight bearing
- load distribution
- restrains excessive motion between segments
Describe the Nucleus pulposus of the IVD:
- gelatinous mass
- Hydrophilic (water loving) glycosaminoglycan (GAG) content
- GAG and water content decrease with age (disc dries out, becomes smaller)
Describe the Annulus Fibrosis of IVD:
- Fibrocartilage
- annular layers with different collagen fiber orientations (adds greatly to strength of disc)
Describe Intradiscal Pressure (IDP)
- Hydrostatic pressure within the disc ensures uniform load distribution
- Nucleus Pulposus is incompressible - resists compressive loads (you push it, it pushes back)
When is IDP the smallest?
when we are sleeping (laying supine)
Rank postures from most stress to least stress on IDP:
- sitting in poor posture (200%)
- bending over (160%)
- seated with decent posture (150%)
- standing erect (normal 100%)
- lying supine (25%)
Wilke study showed a little different results about posture on IDP:
- IDP is lower in unsupported, relaxed sitting than in standing
- Found IDP increased over 7 hours of rest
What plane does the primary motion of the lumbar spine take place in? What degrees at each segment and all together?
- sagittal plane (flexion/extension)
- 12 to 20 degrees at each segment (60 to 100 degrees total)
What plane does the secondary motion of the lumbar spine take place in? What degrees at each segment and all together?
- Frontal Plane
(lateral flexion) - 6 degrees at each segment (36 degrees total)
What plane does the tertiary motion take place around in the lumbar spine? What degrees at each segment and all together?
- Transverse plane
- 2 degrees at each segment (10 degrees total)
What dictates available motion?
ORIENTATION OF THE FACET JOINTS
What plane movement do the lumbar facets allow and restrict?
- allow sagittal and frontal plane motion
- restrict transverse plane motion
Explain the differences in the lumbosacral (L5S1) joint:
- oblique orientation that allows MORE ROTATION and FLEXION and LIMITS LATERAL FLEXION
- from side view: can see articular surfaces of L5S1; looking right at us.
Explain the differences in the lumbosacral (L5S1) joint:
- oblique orientation that allows MORE ROTATION and FLEXION and LIMITS LATERAL FLEXION
- from side view: can see articular surfaces of L5S1; looking right at us.
Describe the arthrokinematics of the lumbar spine:
Flexion:
- Inferior facets of superior vertebra slide upward on the superior facets of inferior vertebra
Extension:
- inferior facets of superior vertebra slide downward on superior facets of inferior vertebra
Right Lateral flexion:
- right inferior facet of superior vertebra slides down, and left inferior facet of superior vertebra slides up on corresponding superior facets of inferior vertebra
Left lateral flexion:
- opposite of right lateral flexion
Rotation:
- ipsilateral gapping, contralateral approximation
T or F: there is no coupled motion in the lumbar spine.
False; there is coupled motion during flexion/rotation in the lumbar spine
What should a PT do when applying coupled motion concepts to the lumbar spine?
use caution
Why do we look at coupled motions in the lumbar spine?
To assess active motion:
- observe compensatory motions that could be attributed to deficient coupled motion (may treat coupled motion to restore primary motion)
To assess passive motion/mobility:
- look at coupling patterns that take place
For clinical intervention:
- guide direction of mobilization, treat restrictions in both motions to restore the primary movement