arthokin mobil path Flashcards
What is a vertebral motor segment?
two continuous vertebral bodies and their common disc
What components of the motion segment dictate the amount and direction of motion?
- disc dictates amount of motion
2. facets dictate direction of motion
What is the muscle activation pattern for upright lumbar flexion?
- pelvis is stabilized by glut maximus, glut medius and hamstrings
- erector spinae eccentrically low trunk
- passive restraints take over in full flexion and the dynamic restraints shut off
What is the IAR of the lumbar motion segment during flexion?
- multiple locations are given including White, Panjabi Rolander in the anterior portion of the disc; Calve in the center of the disc; and Reichman level of the disc but in front of the disc
- as you flex it tends to move down and forward into the end plate or body
What is the muscle activation pattern of the lumbar spine with extenstion?
- Erector spinae active in beginning and end range
2. abdominals slowly increase through the ROM
What is the IAR of the lumbar disc with extension?
multiple theories are given including White and Panjabi posterior to annulus, Calve center of disc, Rolatner anterior disc and Reichman level of disc but anterior and outside the disc
What is the IAR of lumbar side bending?
- Panjabi contralateral side of the center of the disc
2. Grimsby ipsalateral facet
What is the muscle activation pattern for lumbar rotation?
contralteral multifidus, ipsalateral erector spinae, abdominals with multifidus counter acting the flexion moment
What is the IAR of the lumbar rotation?
- Panjabi puts it at the central of the subjacent end plate and slightly contralateral
- Grimsby indicates that it slowly migrates towards the closed pack facet
- before it reaches the closed pack position must shift into the spinal canal to prevent cord compression
How does the IAR change in the lumbar spine with a loss of disc height?
- flexion it moves anterior and superior out side the vertebral body
- extension it moves posterior and inferior
- rotation it moves inferiorly and laterally
How are the facets of the lumbar spine oriented and why is this important?
- upper lumbar have greater sagital orientation and lower lumbar become more transverse
- lower lumbar helps with anterior displacement of the segment
How does disc pathology effect the IAR?
- results in much larger movement in the IAR
- decreased height results in decreased tension of the connective tissues
- greater available ROM results in greater tension on the connective tissues
- greater tension on the connective tissues leads to MTL and further degeneration
What are the weight bearing roles of the disc, facet and UV joint?
- in the cervical spine the weight is transmitted primarily through the UV and facet joints
- in the thoracic and lumbar spine the weight shifts anteriorly into the disc and vertebral bodies
- L5 the weight bearing is in both the disc and facets
What are the coupled motions of the spine?
- cervical spine side bending and rotation the same reguardless of spien position
- L1-L3 side bending and rotation opposition in neutral same in flexed spine
- L5 same as cervical
- L4 is a transition zone and can go either way
What is the ratio of SB to rotation with coupled spine motions?
3 degree side bend for 2 degree rotation
What are the relative rotation segmental ROM of the lumbar spine?
increases distally from 2 to 5 degrees
What are the relative segmental SB ROM of the lumbar spine?
greatest in the middle and least at the bottom from 3 to 8 degrees
What are the relative segmental ROM for flexion of the lumbar spine?
increases distally from 12 to 17 degrees
What is the best way to determine mobility deficits?
relative segmental motion with an awareness of expected ROM
What is a normal of amount of sagital plane motion for the lower lumbar spine?
about 2mm of shear is relatively normal for the lower lumbar spine
How does disc pressure change with changes in posture?
- greatest with standing flexion
- least with supine position
- sitting and slumped posture both increase pressure on the disc
Why might painful end range trunk flexion indicate segmental instability?
as you flexion forward you reach of point where the posterior musculature turns off because and the ligaments and fascia provide the only support for the spine