Spine + Lumbopelvic Rhythm

Intervertebral components

Processes

Apophyseal joints

Interbody Joitns

Purpose of intervertebral porcesses

Attachment for mm (increase mechanical leverage)

Attachment for ligaments (tethering leverage)

Apophyseal joints

Guides intervertebral movement

Allows flex/bend

Interbody Joints

Absorb shock + distribute load across column

Spacers btwn segments to keep height for nerves to exit

Act as pivot for sagittal and frontal planes

Apophyseal Joints are made from?

Adjacent articular facets on processes

Apophoyseal joints are what types of joints?

Plane joints

Are mechanical braces - prevent movement and guide others

Apophyseal joint angulation

Almost vertical in T + L spine to prevent anterior shear

C spine is 45 deg angle to prevent crushing of spinal nerves

• Counteracts gravity

Angulation determines movement of that region along with:

• Relative ratio of disc to vertebral body

• Shape of body

• Mm action

• Ligamentous attachments

Parts of the Intervertebral discs

Nucleus

Annulus Fibrosis

Nucleus make up + job

Avascular

70-90% water; proteoglycans, collagen, elastin, proteins

Absorbs shock

Transfers load across adjacent segments

Annulus Fibrosus

Concentric rings of Collagen and elastin

• Outer rings have strength/elasticity + bind the disc to the spine above/below

• Deeper layers have angled fibers (65 deg) to resist shear, torsion, traction.

Vertebral Endplate

Requires movement to diffuse nutrients to supply the nucleus

Cartilaginous covers superior/interior vertebral body surfaces

IS THE GROWTH PLATE in childhood

Adults: binding site for annulus via fibrocartilaginous layer

Layer facing vertebrae is calcified cartilage (weak bond)

Transmits nutrients to discs

• Aging VEP becomes more calcified/less permeable

VEP + Disc reaction to forces

80% of load goes to body/VEP

20% goes thru facets

Compression

• Rigid w/ fast compression

• Pushes VEP in towards nucleus. Slowly redistributes forces to annulus

• Radial tension from annulus distributes pressures evenly to next body

• Loading distribution varies based on position/activity