Spine Kinematics and Kinetics Flashcards
Human spine
Multi-segmental flexible rod forming the central axis of the neck and trunk
3 normal curves in the spine = Help to dampen or provide flex to the spine function
Junctions of the curves are areas of force concentration, called “transitional zones”
Can be source of pain at these transitional zones…
C-spine
7 vertebrae, atlas (C1), axis (C2), C3-C7
anterior convex (cervical lordosis)
Thoracic spine
12 vertebrae (T1-T12)
posterior convex (primary curve, kyphosis)
Lumbar spine
5 vertebrae
anteriorly convex (secondary curve, lordosis)
Upper cervical spine
OA (C0-1)
AA (C1-2) – atlanto-axial; also has dens of C2 articulating with arch of C1
Mid to lower cervical spine
C3 – C7
“CT Junction” (cervical-thoracic junction – transition zone)
C7 – T2/T3
Thoracic spine
T1 – T11
“Thoracolumbar junction”
T12- L1/L2
Lumbar spine
L1- L5
“Lumbosacral Junction”
L5-S1 – has the greatest motion in the sagittal (flex-ext) planes, and the least motion in the frontal plane (side bend)
Capsuloligamentous structures
Facet joint capsule
Anterior longitudinal ligament (ALL)
Posterior longitudinal ligament (PLL)
Ligamentum flavum
Interspinous and supraspinous ligaments
Tripod of motion –called “spinal segment”
Between each vertebral level, there is:
> one ‘interbody’ joint (2 vertebral bodies with interposing disc)
> 2 facet joints (inferior facets of level above and superior facets of level below
Motion at a “spinal segment”
level above upon the superior facets of the vertebral level below
Approximation of joint surfaces –
caused by compression forces
Separation (gapping) of joint surfaces –
caused by distraction force
Sliding/gliding between joint surfaces –
caused by force tangential to the joint surfaces
Cervical spine – Uncovertebral joints
bony elevations on the superior lateral margins of the cervical vertebrae
these joints articulate with the inferior, lateral aspect of the vertebra above to form the uncovertebral joints = joints of luschka
not true joints
Coupled motion
Two osteokinematic motions occurring at the same time
The most consistent pattern for spine movement is axial rotation associated with lateral flexion
Coupled motion can be due to muscle action, facet alignment, ligamentous tension and spinal curve
Literature on coupled motion in the thoracic and lumbar spine is inconsistent
Coupled motion - Cervical spine
Upper (C0-C2): sidebending coupled with contralateral rotation
Lower (C3-C7): sidebending coupled with ipsilateral rotation
Coupled motion - Thoracic and lumbar spine
Upper thoracic spine similar to cervical spine
Less consistent coupling in lower thoracic and lumbar spine regions
Coupled motion – mid/lower C-spine
Rotation and SB coupled
In the SAME direction is mid-lower C-spine
Ipsilateral coupling
Coupled motion – Thoracic spine
Inconsistent coupling of rotation and SB in the thoracic spine
Coupled Motion – Lumbar spine
Coupling pattern depended on which motion was used to initiate movement
In extension
> SB 1st – contralateral coupling
> Rotate 1st – L1-L4 contralateral coupling, L5-S1 ipsilateral coupling
In flexion
> Ipsilateral coupling whether SB 1st or rotate 1st
Great variability and unpredictability between LBP and asymptomatic subjects
Ribs
Functions
> Protective barrier for vital organs
> Stiffens thoracic spine – increases inertia
> Strengthens thoracic spine – increases energy absorption during trauma
Ribs 1-7
Direct sternal connection
Ribs 8-10
Indirect sternal connection
Ribs 11-12
No sternal connection
Kinematic motion Ribs
Ribs 1-6
> Move more in A-P
> “Pump handle”
Ribs 7-10
> Move more lateral
> “Bucket handle”
Ribs 1-4 stiff, strong, rigid, Relative immobility
Ribs 5-12 greater elasticity, fracture potential
Muscles of respiration = Inspiration
Quiet diaphragm, scalenes, intercostal muscles
Forced SCM, upper trap, pec major/minor, subclavius, external intercostals
Muscles of respiration = Expiration
Quiet none
Forced abdominals, pec major, internal intercostals
TRUNK MUSCLES
- Create/control trunk motion
- Stabilize/maintain the relationship of individual
- Control trunk for meaningful limb movement
- Control center of mass of body relative to base of support
