Introduction To Spine Flashcards
What are the mobility functions of the spine?
- provide movement in trunk
- provide change in trunk posture
- augment movements of UE and LE
What are the stability functions of the spine?
- maintain upright posture
- maintain head in stable position
- protect spinal cord
- protect viscera
primary curve- convexity and regions of spine
Posterior convexity
Thoracic and sacral
Secondary curvature- convexity and regions
Anterior convexity
Cervical and lumbar
What is the advantage of curves of spine
- resists higher compressive loads
- 10 fold more resistance to axial compression compared to straight rod
What is the function of the vertebra?
- weight bearing
- resists compressive load
What on the vertebrae resists helps compressive force
Trabeculae
Function of pedicles
Transmits tension and bending forces from posterior elements to vertebral bodies.
Function of lamina
Transmit forces from articulations, transverse and spinous processes to pedicles
What are the 2 functions of IV disc?
- Increase motion
- Transmit load
What is the relationship between ratio and mobility of the IV disc
The greater the ratio between disc thickness and vertebral body height, the greater the mobility of spine
Components of IV disc
Nucleus pulposus (inside) Annulus fibrosus (around nucelus pulposus) Vertebral end plate (superior and inferior of disc)
what kind of cartilage are cartilaginous end plates?
Hyaline cartilage closer to the vertebral body
Fibrocartilage closer to the nucleus pulposus
What is nucleus pulposus made of? What is its function?
-70-90% water
Type II collagen (resist compression)
-Distributes load to entire disc
Deforms when compressed and walls stretch
What motions put the MOST stress on disc?
Flexion and rotation
What is annulus fibrosus made of an what is its function?
-60-70% water
Type I collagen in outer portion
-resists greater tensile forces
What do Sharpey fibers connect?
Annulus to end plate
Explain disc thickness-vertebral body height ratio
Greater the ratio between disc thickness and vertebral body height, the greater the mobility.
(^ ratio, ^ movement)
What region as the greatest disc-vertebral height ratio
Cervical
What happens to disc-vertebral height ratio when we grow old
Increase in age, nucleus dries up, ratio decreases, vertebrae get closer to each other, lose mobility.
Blood supply to IV disc
No blood supply from major arteries
Capillary plexus in base of end plate (supplies outer surface)
Innervation to IV disc
Outer 1/3 to 1/2 of annulus fibrosis is innervated
Branches of vertebral and sinuvertebral nerves
How many degrees of freedom in interbody joints
6
- gliding
- distraction/compression
- A/P translation
- lateral tilting
- rotation
- A/P tilting
Explain meniscoid in zygopophyseal joint
Flex- mensicoid goes up
Extend- meniscoid goes down
It doesn’t cover whole joint so it has to move
What kind of joint is zygopophyseal joint
Diarthrodial synovial
Zygopophyseal articulation in cervical region (limit/easiest)
Limit- rotation and SB
Easiest- flex/ext
Zygopophyseal articulation in thoracic region (limit/easiest)
Limit- flex/ext
Easiest-SB
Zygopophyseal articulation in lumbar region (limit/easiest)
Limit- rot and SB
Easiest- flex/ext
Coupling motions- what 2 actions occur together
Rotation and lateral flexion
What does motion depend on?
- orientation of facets
- ligament function
- muscle limitation
- size of disc (^ratio, ^mobility)
Motion in flexion (arthro, foramen size, spinous process, annulus)
Anterior glide and tilt Foramen size increases Spinous process separate Anterior annulus compresses Posterior annulus stretches
Motion in extension (arthro, foramen size, spinous process, annulus)
Posterior glide and tilt Foramen size decreases Spinous process move close together Anterior annulus stretches Posterior annulus compresses
Motion in lateral flexion (arthro, foramen size, spinous process, annulus)
Superior facet laterally tilts rotates and translates on inferior Foramen narrow on ipsilateral side Foramen widened on contralateral side Annulus compressed on concave side Annulus stretched on convex side
How many vertebrae in each spine region?
Cervical (7) Thoracic (12) Lumbar (5) Sacral Coccygeal
Annulus fibrosis function and region
- Resists distraction, translation, rotation of vertebral bodies
- cervical, thoracic, lumbar
Anterior longitudinal ligament (ALL) function and region
- limits extension
- C2 to sacrum (well developed in cervical, lower thoracic, and lumbar)
Anterior atlanto-occipital ligament function and region
- Limits extension
- C2 to occipital bone
Posterior longitudinal ligament (PLL) function and region
- Limits forward flexion
- C2 to sacrum (broadened in cervical and thoracic, narrow in lumbar)
Tectorial membrane function and region
- limits forward flexion
- C2 to occipital bone
Ligamentum flavum function and region
- Limits forward flexion (especially in lumbar resisting laminae separation)
- C2 to sacrum (long, broad, and thin in cervical and thoracic)(thickest in lumbar)
Posterior atlanto-occipital ligament function and region
- Limits flexion
- C1 and C2
Supraspinous ligament function and region
- limits forward flexion
- thoracic and lumbar. Weak in lumbar
Ligamentum nuchae function and region
- Limits forward flexion
- cervical (EOP to C7)
Interspinous ligament function and region
- Limits forward flexion
- primarily in lumbar, well developed
Intertransverse ligament function and region
- Limits contralateral lateral flexion
- primarily lumbar region
Alar ligament function and region
-Limits ipsilateral head rotation
Limits contralateral lateral flexion
-C1 & C2
Iliolumbar ligament function and region
- Resists anterior sliding of L5 and S1
- Lower lumbar region
Zygopophyseal ligament function and region
-Resists forward flexion
Resists axial rotation
-strongest at cervicothoracic junction and thoracolumbar region
