lumbar biomechanics Flashcards
Which portion of the IVD allows for stress resistance in many directions?
annulus fibrosus
Which portion of the IVD is composed of type I AND II collagen? In lumbar
annulus fibrosus
-provide for a balance between strength and flexibility
Which portion of the IVD is composed of 70-90% H2O?
nucleus pulposus
Which portion of the IVD is composed of elastin/type II collagen? In lumbar
nucleus pulposus
Which portion of the IVD is responsible for nutrient transport?
nucleus pulposus
Which portion of the IVD functions as a growth plate in children?
vertebral endplate
What is the height (%) is the endplate in the IVD at birth and in adult
children: 50%
Adult: 5%
Which portion of the IVD is continuous with the annulus fibrosus?
vertebral endplate
What motions does the iliolumbar ligament resist?
flexion, extension, axial rotation, and side bending (at L5-S1)
What motions does the sacrotuberous ligament stabilize?
against flexion of the sacrum
What motions does the sacrospinous ligament resist?
flexion of the sacrum
What is the thoracolumbar fascia? What does it do?
- connective tissue traveling from T12 to the iliac spine and iliac crest
- attachment site for muscles
- stabilized the spine
Arthokinematics of zygapophyseal joint: flexion
- Anterior translation
- Anterior rotation
Arthokinematics of zygapophyseal joint: extension
- Posterior translation
- Posterior rotation
Arthokinematics of zygapophyseal joint: rotation
-ipsilateral- posterior glide
-contralateral- anterior glide
- type 1 coupling (only in extend position)
mostly occurs in thoracic spine
Arthokinematics of zygapophyseal joint: side bending
ipsilateral- inferior glide/approximation
contralateral- superior glide/gapping
- type 1 coupling (only in extend position)
Closed position, open position, and capsular pattern in lumbar
closed: full extension
open: midway between flexion and extension
capsular pattern: side bending> flexion/extension
What is the capsular pattern for sacroiliac joint?
pain when the joints are stressed
Arthokinematics sacroiliac nutation (flexion)
- superior sacrum moves anteriorly
- inferior sacrum moves posteriorly
Arthokinematics sacroiliac counternutation (extension)
- superior sacrum moves posteriorly
- inferior sacrum moves anteriorly
Normal lumbopelvic rhythm
40 deg lumbar flexion
70 deg hip/pelvic flexion
Decreased plevic rhythm
- increased lumbar flexion
- increased stress of lumbar spine
Decreased lumbar rhythm
- increased hip/pelvic flexion
- increased stress of hips/pelvis
Describe phase 1 of lumbopelvic rhythm
- Hamstrings fire/gluteus maximus fire
- Lumbar extensor begin to fire
- Hip/pelvic flexion decreased
Describe phase 2 of lumbopelvic rhythm
- Hamstrings/gluteus maximus continue to fire
- Lumbar extensors increase force they are producing
- Lumbar flexion decreased
- Hip/pelvic flexion back to neutral
Describe phase 3 of lumbopelvic rhythm
• Lumbar and pelvis/hip neutral
Components of an anterior pelvic tilt
- Tight: lumbar extensors and hip flexors
- Increased lumbar lordosis
- Posterior tilting of vertebrae
- Anterior migration of nucleus pulposus
Components of a posterior pelvic tilt
- Tight: anterior abdominals and hip extensors
- decreased lumbar lordosis (increased kyphosis)
- anterior tilting of vertebrae
- posterior migration of nucleus pulposus
What is a spondylolisthesis?
When once of the vertebrae slips forward onto the vertebra below it
What is disc degeneration?
loss of fluid in the intervertebral discs
What is ankylosing spondylitis?
chronic inflammatory disease that affects the spine, SI, and hips that can eventually lead to body fusion of the joints
