M1 Reading Guide 2 Flashcards
What bony structure (s) create the intervertebral foramen?
lateral opening between adjacent vertebrae
What passes through the IVF?
passageway for spinal nerve roots exiting the vertebral canal
Adult discs are (vascular/avascular)
essentially avascular
Adult discs are essentially avascular, so how do they receive nutrition?
passive diffusion
What is the effect of movement on discs?
movement increases diffusion of nutrients to discs
The annulus consists of how many layers?
- 15-25 concentric layers of collagen fibers
- elastin interspersed parallel to collagen rings
The outer layers of the AF consist of:
type I and type II collagen
Type I and Type II collagen provides this for the AF
- strength
- flexibility
This part of the disc contains the disc’s only sensory nerves
Annulus fibrosus
What is different about the outer vs. the inner layers of the annulus?
- inner layers have less type I collagen and more water
- outer peripheral rings contain blood vessels
What happens to the anterior annulus during flexion?
compressed
During rotation, what part of the annulus is taut?
only the fibers oriented in the direction of rotation becomes taut
During rotation, what happens to intradiscal pressure?
increases
Why does intradiscal pressure increase during rotation?
due to approximation of vertebral bodies
What position(s) of the lumbar spine cause the least intradiscal pressure?
lying down
What position(s) of the lumbar spine cause the most intradiscal pressure?
standing in flexion with load in hand
Why is the ALL so much wider and stronger in the lumbar spine than the PLL?
limits extension and excessive lumbar lordosis
What is different about the ligamentum flavum from other ligaments and why does this matter?
- elastic properties of the ligament allows it to shorten and retract on itself rather than buckling as a typical ligament would
- minimizes compression of the spinal cord during extension
