Cervical and thoracic regions Flashcards
What are the primary and secondary curves of the spine?
Primary:
- kyphosis (thoracic and sacral)
Secondary:
- Lordosis (cervical & lumbar)
What happens to the cervical curves during sagittal plane movement?
Flexion: decrease/flatten out lordotic curve
Extension: increases lordotic curve
What happens to the thoracic curves during sagittal plane movement?
Flexion: increases kyphotic curve
Extension: decreases/flattens out kyphotic curve
What happens to the lumbar curves during sagittal plane movement?
Flexion: decrease/flatten out lordotic curve
Extension: increases lordotic curve
What happens to the sacral curves during sagittal plane movement?
- Fixed, fused together so doesn’t move
What is one negative of having spinal curves?
- shear forces
- can lead to spondylolisthesis
Where does the LoG fall for each spinal curve?
- falls on the concave side of each curve
- Anterior = kyphotic
- Posterior = lordotic
Is it a good thing or bad thing that the LoG falls on the concave side of each curve?
- Good!
- helps keep curves in line & decreases work needed from ligaments/muscles to maintain good posture & ideal LoG
What are anatomical factors for ideal posture?
- shape of discs or vertebral bodies
- facet joint orientation
- ligament composition
- muscles stiffness
What happens to the PLL as it descends through the lumbar spine?
- it starts to narrow as it moves down
How does the narrowing of the PLL affect the discs in the lumbar region?
- hard to stop a bulging disc which leads to increased chances of bulging disc injury
Describe a “motion segment” and its components
Segments of the vertebral column that allow movement
- transverse & spinous processes
- apophyseal joints
- interbody joints
Define osteokinematics as it relates to movement at a spinal motion segment
- 3 degrees of freedom
- AoR through interbody joints
- movement is described by what the joint is doing and where the front goes
Define arthrokinematics as it related to movement at a spinal motion segment
- describes motion of the facets
- sliding, gapping, approximation
Define the AoR as it related to movement at a spinal motion segment
- interbody joint is the AoR
What are the functions of the interbody joints?
- absorb & distribute loads
- glues vertebrae together
- approximate axis of rotation
- discs = spacers
What are “intra-articular inclusions?”
- small, accessory structures that exist around joints
EX: subscapular fat pads & fibro-adipose meniscoids (FAMs)
How can these intra-articular inclusions affect facet joints?
- fill up spaces b/w facet joints
- help dissipate compressive forces
- partially cover articular cartilage
- FAMs can become impinged during whiplash
- can lock facet joints
What facet orientation allows for different kinds of movement?
- more vertical facet orientation = more frontal/sagittal plane movement
- more horizontal facet orientation = more axial rotation
What part of the intervertebral disc has nerve and blood supply?
- annulus fibrosus -> outer layer innervated/vascularized
How does the annulus help dissipate loads?
- comprised of collagen & elastin w/ layers
- alternates orientation w/ each layer
- oriented 65 degrees from vertical & 25 degrees from horizontal
How does the disc get nutrition?
- diffusion
Why are we taller in the morning than in the evening?
- disc swells overnight
Why would a disc be more painful in the morning?
- weight-bearing compresses disc & pushes water out
- painful for those w/ issues
Explain the process of disc degeneration
1) Aging, excessive, or abnormal mechanical loading -> reduced permeability & increased calcification of endplates
2) reduced nutrient flow to disc
3) Inhibition of cellular metabolism & proteoglycan synthesis -> can’t attract & retain water -> decreased ability to absorb & transfer loads
How does the disc help transmit loads through the spine at each motion segment?
- endplates move toward nucleus
- nucleus slowly deforms radially (which is incompressible)
- annulus resists radial deformation
- pressure transmitted to other vertebra
How does the disc respond to movement of the spinal motion segments in the sagittal plane?
Flexion:
- compression anterior
- stretches posterior
- nucleus migrates posterior
Extension:
- compression posterior
- stretches anterior
- nucleus migrates anterior
How does the disc respond to movement of the spinal motion segments in the frontal plane?
Lateral flexion:
- compression ipsilateral
- stretches contralateral
- nucleus migrates contralateral
How does the disc respond to axial compression?
- resisted by discs & vertebral bodies
- transmitted through discs to end plates to vertebral bodies
How does the disc respond to bending?
- compression 1 side
- tension other side
- nucleus migrates away from compression
- creep of viscoelastic structures
How does the disc respond to torsion?
- resisted by vertebral bodies, discs, facets
- annular fibers rupture w/ torsion & axial compression & forward bending
How does the disc respond to shear?
- vertebral translation
- resisted by facets & discs
- disc creep leave facets only to resist
Explain the spinal coupling that occurs in the mid-lower cervical spine
- lateral flexion + ipsilateral rotation
What happens if the transverse ligament of the atlas is ruptured?
- Dens is free to move which could injury spinal cord
- atlas slips anteriorly
What is meant by the “transitional zone” when discussing the spine?
- the change of apophyseal joint orientation
What muscles is used when you turn your head to the left?
- right SCM
What is spinal coupling?
- movement in 1 plane associated with automatic movement in another plane
What are some explanations for spinal coupling?
- muscle action
- facet alignment
- pre-existing posture
- attachment of ribs
- stiffness of connective tissues
- normal spinal curves
What happens if an Alar ligament is ruptured?
- resists rotation
- if ruptured, excessive movement/rotation to contralateral side
What are the arthrokinematics of A-O joint flexion?
- convex occipital condyles roll anterior and slide posterior
What are the arthrokinematics of A-O joint extension?
- convex occipital condyles roll posterior and slide anterior
What are the arthrokinematics of A-O joint rotation?
- not much movement
What are the arthrokinematics of A-O joint lateral flexion?
Right:
- roll right, slide left
Left:
- roll left, slide right
What are the arthrokinematics of A-A joint flexion?
- atlas tilts about 15 degrees forward
What are the arthrokinematics of A-A joint extension?
- atlas tilts about 15 degrees backward
What are the arthrokinematics of A-A joint rotation?
- atlas twists around dens
contralateral vertebral artery taut
What are the arthrokinematics of C2-7 flexion?
- top vertebra slides superior & anterior
OOP
What are the arthrokinematics of C2-7 extension?
- top vertebra slides inferior & posterior
CPP
What are the arthrokinematics of C2-7 rotation?
- ipsilateral facet slides inferior and posterior
- contralateral facet slides superior and anterior
What are the arthrokinematics of C2-7 lateral flexion?
- ipsilateral facet slides inferior and posterior
- contralateral facet slides superior and anterior
What does protraction cause the mid-lower cervical spine and upper cervical spine to do?
Mid-lower:
- flexion
Upper:
- extension
What does retraction cause the mid-lower cervical spine and upper cervical spine to do?
Mid-lower:
- extension
Upper:
- flexion
What vertebral artery becomes taught with right cervical rotation?
- left vertebral artery
always contralateral artery becomes taut
Why doesn’t the upper cervical spine follow the natural coupling pattern of the rest of the cervical spine?
- to keep our gaze level so the coupling pattern has to change to stay level
What happens during lateral flexion of upper cervical coupling pattern?
A-A:
- ipsilateral lateral flexion = capital rotation contralaterally
What happens during rotation of upper cervical coupling pattern?
A-O:
- capital rotation right = lateral flexion left
What cervical spine position increases foraminal opening?
- flexion
- contralateral rotation &/or lateral flexion
What cervical spine position decreases foraminal opening?
- extension
- ipsilateral rotation &/or lateral flexion
What action does the SCM perform?
- flexes mid/lower cervical spine
- extend upper cervical
- unilateral contraction turns capital to opposite side
What action do the scalenes perform?
- laterally flexes neck (unilateral contraction)
- stabilizes
What action does the longus colli perform?
- flexes neck
- reduces lordosis
- stabilizes
What action does the rectus capitis anterior & lateralis perform?
- flexes & stabilizes
- laterally flexes
Rectus capitis anterior:
- flexes A-O
Rectus Capitis lateralis:
- laterally flexes A-O
What action do the splenius cervicis & capitis perform?
Unilateral:
- laterally flex
- ipsilateral rotation
Bilateral:
- extension
What muscles would you want to train for neck stability?
- scalenes, levator scapula, longus colli, traps
Shorter segment muscles:
- multifidi
- fine, motor control
Longer segment muscles:
- guy wires for vertical stability
Why do osteophytes develop in the cervical spine and how do they affect other structures?
- dehydrated, degenerated discs leading to increased compression of vertebra
- leads to increased bone formation causing closing/decreased volume for exiting nerve roots
Explain the effects of whiplash on structures of the neck
- hyperextension
- ALL injury, Alar ligaments, longus colli/capitis
- compresses facets, discs, other posterior elements
- spasms of muscles in the area
What is regional interdependence?
- one muscles action depends on stabilization force of another
EX:
- longus colli stabilizes neck = trap can elevate shoulders
Describe the arthrokinematics of the thoracic facets during flexion
- inferior facet of superior vertebra slides superior & anterior
Describe the arthrokinematics of the thoracic facets during extension
- inferior facet of superior vertebra slides inferior and posterior
Describe the arthrokinematics of the thoracic facets during rotation
- facets slides contralaterally
R rotation = facets slide left
Describe the arthrokinematics of the thoracic facets during lateral flexion
- ipsilateral facet slides inferior
- contralateral facet slides superior
What muscles are in the erector spinae group?
- spinalis
- longissimus
- iliocostalis
What muscles are in the transversospinal group?
- semispinalis
- multifidi
- rotatores
What muscles are in the short segmental group?
- interspinalis
-intertransversarius
What is the flexion-relaxation phenomenon?
- erector spinae ecc contract during flexion until about 2/3rds then are silent (stretch is still active)
- this point passive tension is enough to create moment for flexion
How does the flexion-relaxation phenomenon adversely affect the lower lumbar spine?
- losses ability to oppose/resist anterior shear of lumbar vertebra
How is the psoas major unique in its line of force throughout the lumbar spine in the sagittal plane?
- increases lumbar lordosis & anterior tilts pelvis on fixed femur
- upper lumbar spine = extensor
- lower lumbar spine = flexor
MAJOR lumbar stabilizer
What pathology can occur at the T-L junction?
- hyperlordosis could occur (cerebral palsy)
Traumatic paraplegia:
- hyperflexion torque
- fracture/dislocation
- spinal cord injury
How is scoliosis named?
- described by the convexity
EX: right thoracic scoliosis
What is the difference between function and structural scoliosis?
Functional:
- corrected w/ postural shift
Structural:
- fixed; can’t be corrected
- adolescent females > males (4x more)
What coupling occurs with scoliosis?
- contralateral spinal coupling
- right lateral flexion = left rotation
- right rib hump side of convexity
- vertebral bodies face left & spinous processes face right
How does thoracic kyphosis affect the moment created by the line of gravity?
- increases gravitational EMA of thoracic flexion
What affect does thoracic kyphosis have on the spine and thorax?
- impacts inspiration, vital capacity, & balance (shifts CoM forward)
- leads to increased flexion torque of thoracic spine & extensive torque on cervical spine
What are ROM norms for cervical flexion/extension?
Flex:
- 45
Ext:
-45
What are ROM norms for cervical rotation and lateral flexion?
Rotation:
- 60
Lateral flexion:
- 45