Lumbar Biomechanics Flashcards
Describe Type I (Neutral) Fryette mechanics.
Sidebending and Rotation are coupled to opposite sides
Describe Type II (Non-neutral) Fryette mechanics.
Sidebending and rotation are coupled to the same sides
What is the exception to Fryette’s rule?
L5/S1 - lots of spinal anomalies here; trauma can also negate Fryette mechanics
In lumbar kinesiology, motion is….
permitted by bones and joints, restrained by ligaments, and produced/stabilized by muscles
What is the functional range of the lumbar spine?
T11-L5
What is the lumbar spine designed for?
weight bearing design
In what plane do the lumbar facets orient?
Sagittal plane
Lumbar superior articular facets face…
posteromedially
Lumbar inferior articular facets face…
anterolaterally
How does lumbar osteology affect movement?
allows good forward bending and back bending; discourages rotation and sidebending
Where is the most movement in the lumbar spine?
L4 on L5 14-21 degrees
L5 on S1 18-22 degrees
How much sidebending is in lumbar vertebrae?
10 degrees each segment
How much rotation is in L1-L3? L4 & L5?
L1-L3 - 2 degrees each segment
L4&L5 - 3-4 degrees each segment (most rotation in lumbar thoracic)
How do intervertebral discs receive nutrients?
diffusion (they are avascular)
Motion loss can impair nutrition leading to____
premature disc degeneration
Lumbar discs are thicker anteriorly or posteriorly?
anteriorly contributing to lumbar lordosis
What is the purpose of the fiber arrangement of the annulus?
checks rotary motion and screws down the disc
Where is the nucleus pulposus located?
posterior surface of disc
When does disc degeneration begin in men? women?
Men - 11-20
Women - 21-30
Where is the most common herniation?
L5/S1
Does trauma alone cause herniation?
No, must be coupled with degeneration
This ligament reinforces the strength of the disc posteriorly in the midline.
Posterior longitudinal ligament
Describe the impact of the narrowing and weaker posterior longitudinal ligament on discs.
In lumbar region causes higher likelihood of disc herniation
List the two types of ligaments and their purposes.
Check ligaments (forward backward and lateral bending, rotation); kinetic ligaments (absorb energy)
What are the 4 forward bending check ligaments?
supraspinous, interspinous, posterior longitudinal, capsular ligaments
What feel would present with a torn supraspinous ligament?
tender, boggy
Name the kinetic ligament and its function.
ligamentum flavum; stores kinetic energy to assist musculature in returning spine to upright position
Name the sidebending check ligament
intertransverse check ligaments
Which ligaments are injured in the classic lumbosacral sprain and strain?
Iliolumbar ligaments (rotational check ligaments)
How do discs check rotation?
alternating direction of fibers in adjacent lamina of disc
This backbending check ligament is broad and flat and reinforces the disc anteriorly and is twice as strong as the posterior longitudinal ligament.
Anterior longitudinal ligament
Anterior lipping and osteophyte formation is seen when?
When traction on anterior longitudinal ligament causes bone reformation
This fascia is critical to the maintenance of lumbar stability.
Thoracolumbar fascia
What help keeps the thoracolumbar fascia taut?
Always positive pressure in abdomen
What can generate instability in the thoracolumbar fascia?
weakness, hernias, incisions, pregnancy
Which muscles are involuntary and used to stabilize?
short muscles
Which muscles are voluntary and movers of the spine?
long muscles
Which muscles respond to viscera-somatic and somato-somatic reflexes?
deep paraspinal muscles (intertransverse, interspinalis, rotator brevis and longus)
List the attachment, action and innervation of the intertransverse muscles.
Attachment: between lumbar t.p.
Action: segmental sidebending/stabilization
Innervation: posterior primary division of spinal nerves
List the attachment, action and innervation of the interspinalis muscles?
Attachment: T11 to S1
Action: segmental Extension/ stabilizer
Innervation: posterior primary division of spinal nerves
List the attachment, action and innervation of rotator brevis and longus.
Brevis: tp of spinous process 1 segment above
Longus: tp of spinous process 2 segments above
Action: rotate to opposite side/stabilizer
Innervation: posterior primary division of spinal nerve
What initiates flexion of the trunk?
rectus abdominus; further control by erector spinae muscles
Which muscles extend the spine?
Iliocostalis lumborum, longissimus thoracis, spinalis thoracis, multifidus (I love spaghettis mom)
When acting unilaterally what movement do the voluntary muscles create? combined with internal obliques?
sidebending; rotation
What other 5 muscles attach to the lumbar spine?
diaphragm, psoas major, quadratus lumborum, latissimus dorsi, serratus posterior inferior
Diaphragmatic overuse (asthma or COPD) will tend to create what dysfunction?
flexed dysfuntions of upper lumbar segments
Upper lumbar somatic dysfunction mechanically interferes with the function of ____ and results in _____?
diaphragm; shortness of breath
Psoas major is active in the standing or seated position?
seated
Prolonged sitting causes?
shorten psoas, anterior tilt of pelvis and increase lumbar lordosis
Which nerves are vulnerable to compression by hypertonicity of psoas major?
lumbar nerve roots which pass anteriorly between proximal attachments
Acute psoas spasm causes sidebending to same or opposite side of spasm?
same
Psoas spasm causes type 1 or type 2 Fryette mechanics?
Type 2; flexed, rotated and sidebent to the same side
If there is a psoas spasm with extended dysfunction of L1-L3 which gets treated first?
Treat L1-L3 extension first
If there is a psoas spasm with flexed dysfunction which gets treated first?
Psoas
Hypertonicity of the quadratus lumborum creates sidebending to the same or opposite side?
same; usually group curve
Problems with the latissimus dorsi usually causes pain in which region?
shoulder
List an accessory muscle for forced exhalation.
Serratus Posterior Inferior
If ribs are held in fixed inhalation, unilateral contraction of serratus posterior inferior will rotate L1-L3 (towards or away) from side of muscle contracture.
away
Asthma or emphysema can create flexed postures which can provoke what type of dysfunction?
Type II
Batson’s veins are the principle route of travel for? and clogs in the IVC can cause?
infection and metastasis of pelvic cancers; headaches
What maneuver can you use to reproduce symptoms?
Valsalva
Which nerve root is most susceptible to neuropathy?
S1 due to length
Fibrosis of nerve roots or entrapment will cause nerves to become ____?
ischemic
Blood flow in vasa nervorum is reduced when a nerve is stretched ____% and blood flow ceases entirely at ____ %.
8%; 15%
