Lumbar Spine/Ribs Flashcards
Describe the structure of the lumbar vertebrae.
- Large body
- Vertebral foramen > than thoracic but < cervical
- L5 wedge shaped body for transition
How are the facet joints oriented in the lumbar spine?
- Curved and biplanar (frontal and sagittal plane)
- Anteriorly = aligned with frontal plane resisting anterior shearing forces
- Posteriorly = aligned nearly with sagittal plane allowing for greater flex/ext but restricting rotation
What is the lumbrosacral angle?
formed by 5th lumbar vert and 1st sacral segment
Why is the lumbosacral junction an area susceptible to injury and shearing?
increased angle = increased lordosis of lumbar spine which increases amount of shearing stress
Describe the intervertebral discs of the lumbar spine.
- Largest discs in the spine
- Able to resist tensile forces in nearly all directions
What kind of joints make up the sacroiliac joint?
- Anterior synovial joint with articular surfaces
2. Posterior syndesmosis with tuberosities
What is the structure of the pubic symphysis and what muscles provide support to this area?
- Cartilaginous joint
- Anterior portion of joint reinforced by transversus abdominis, restuc abdominis, internal oblique, adductor longus
What are the osteokinematics of the lumbar spine?
Flex/Ext
Lateral flex
Rotation
What are the arthrokinematics of the interbody joints and facet joints for flex/ext:
Flex - facet glide superior and anterior
Ext - facet will glide inferior and posterior
Greatest motion flex/ext occurs in which part of lumbar spine?
Inferior segment
What are the arthrokinematics of the interbody joints and facet joints for side bending:
- Superior glide in facet contralateral to side bend
- Inferior glide in facet ipsilateral to side-bend
Greatest motion of side bending occur in which part of lumbar spine?
Superior lumbar
True/False: coupling pattern in inconsistent in lumbar region
True
What are the arthrokinematics of the interbody joints and facet joints for rotation:
- Facet contralateral to rotation with approximate
- Facet ipsilateral to rotation will distract
Greatest motion of rotation occur in which part of lumbar spine?
superior lumbar segments
What is the normal lumbo-pelvic rhythm for flexion and for extension?
Bending over to touch toes:
- Flexion- initially lumbar flexion followed by anterior tilt of pelvis
- Extension - posterior tilt of pelvis followed by extension of lumbar
What two things does movement of the pelvis do?
- Increases motion
2. Reduces amount of flexibility required of lumbar region
What muscles provide muscular stability to the trunk? Which are intrinsic?
Intrinsic - semsispinalis, multifidi, rotatores, interspinalis, intertransversarius
What muscles provide muscular stability to the trunk?Which are extrinsic?
Extrinsic - rectus abdominis, external/internal oblique, transverse abdominis, erector spinae, quadratus lumborum, psoas major
Why is a stable core important?
- Provides structural integrity
- Optimizes postural alignment
- Limits excess micromotion
- Provides firm base for extremities to move
What is the muscle activation that occurs with a full sit-up?
Trunk flexion phase - abdominals
Hip flexion phase - continued activation of abdominals with hip flexor muscles
Weak abdominals will result in what during a full sit-up?
Early hip flexion due to hip flexor dominance = increase compression of lumbar spine
What are recommended lifting mechanics? Why are these strategies preferred?
- Reduce force required of extensors with lifting
1. Reduce velocity of lifting
2. Reduce magnitude of external load
3. Reduce length of EMA
What is the stoop lift?
- Greater flexion of lower back
- Greater extension force required from low back and truck due to longer EMA
- Large compression and shear forces on disc
What is the squat lift?
- Max knee flexion
- EMA is reduced between load and trunk and decrease extensor torque
- Safer
What is the difference between nutation and counter-nutation compared to anterior and posterior pelvic tilting?
Nutation/counternutation - describe movement of sacrum on innominate
Ant/post pelvic tilt - describe movement of innominate bones
Anterior pelvic tilt:
ASIS and pubic symphysis move inferiorly
Posterior pelvic tilt:
ASIS and pubic symphysis move superiorly
Nutation:
Sacral promontory moves anteriorly and inferiorly and sacral apex moves posteriorly and superiorly
Counternutation:
sacral promontory moves posteriorly and superiorly and sacral apex moves anteriorly
True/False: near vertical orientation of SI joint could result in slipping
True
How does nutation provide stability?
Provides increased compression improving stability
What are forces contributing to nutation torque?
- Gravity (1st line stability)
- Stretched ligaments (interosseous and sacrotuberous lig)
- Muscle activation
What is the close-packed position of SI joint?
Full nutation
What muscles reinforce the SI joint?
- Erector spinae & lumbar multifidi
- Diaphragm and pelvic floor
- Abdominal muscles
- Hip ext
- Lats
- Iliacus and piriformis
How does different posture/alignment effect the lumbar spine in sitting?
- Anterior pelvic tilt with lumbar extension - alleviates posterior pressure
- Posterior pelvic tilt with lumbar flex - anterior pressure on disc and tension in zygoapophyseal joints
What are the primary functions of the lumbar spine?
- Provide support for weight of upper body
- Withstand compressive loads applied with muscle contraction
hat are the primary functions of the pelvis?
- Transmit force of vert column to lower extremities
- Relieve stress on pelvic ring created by movement of trunk and lower extremities
