Exam 2 IVD Part 1 Flashcards
T/F: There are 23 discs in the human adult given a numeric name based on the segment below.
False; segment above
T/F: The unique structure of the IVD allows for its function in both weight-bearing and motion.
True
How much of the height of the vertebral column is composed of the discs?
20-33%
What are the 3 parts of the IVD?
nucleus pulposus, annulus fibrosus, and cartilaginous end plates
T/F: A greater ratio of IVD disc height to vertebral body height means less spinal segmental mobility.
False; greater disc to vertebral body height ratio=greater mobility (more disc, more movement)
Where is the ratio of disc to vertebral body the greatest? the least?
cervical;
thoracic
(most mobility in cervicals)
Generally, how much of the nucleus pulposus is composed of water? When is the water content at its highest?
70-90%; at birth (dry out over time)
Bigger discs have more capacity to change size. What is this known as?
creep
T/F: Lumbar IVD nuclei are more anterior than central.
false; more posterior than central
How much of the total disc area is compose of nuclei in the lumbar IVDs?
30-50%
T/F: Cervical discs are less defined with only a thin strip of annulus in the back.
True
What part of the IVD is composed of fibrous tissue in concentric laminated bands?
Annulus Fibrosus
T/F: Fibers in adjacent bands of the annulus fibrosus run parallel to each other.
False; same direction within a single band, but opposite directions in any two adjacent bands
T/F: Annular fibers form an angle of about 45 degrees to the vertebral body.
False; about 30 degrees
What are annular fibers attached to?
cartilaginous endplates in the inner zone, and the vertebral body in the peripheral zone
What are the especially strong fibers called that attach the annulus to the vertebral body?
Sharpey’s fibers
T/F: the ALL and the PLL reinforce the annular fibers,.
True
T/F: the PLL widens from cervical to lumbars to compensate for the increasing size of the vertebral bodies.
False; PLL narrows inferiorly until it covers only about 50% of the lower lumbar discs
What is the weakest and hence the most likely to be injured part of the annulus?
posterolateral aspect
What is the most lilely spot for a disc herniation in the lumbar spine?
posterolateral aspect
t/F: fibers of the annulus attach the endplate to the disc.
True
T/F: the central portion of the cartilaginous end plate is fairly impermeable and thus, diffusion of nutrients occurs in the outer portion.
False; vice-versa
T/F: the end plate supplies the nucleus pulposus with most (or all) of its nutrition.
True
T/F: the cartilaginous end plates help to prevent the vertebral bodies from hypertrophy.
False; prevent pressure atrophy
T/F: the cartilaginous end plates maintain the nuclear and annular borders.
True
T/F: Typical, healthy discs are well vascularized.
False; avascular
Where do annular fibers receive their blood supply? nucleus pulposus
adjacent soft tissues;
vertebral bodies
T/F: nutrients can diffuse into the disc from the end plates.
True
T/F: A typical, healthy IVD is avascular and aneural.
True
T/F: The IVD undergoes rapid degeneration and has limited self repair.
True
T/F: While sleeping, IVDs have an increased hydrostatic pressure and an increased osmotic pressure which increases the resistance to forces.
False; lower hydrostatic pressure, higher osmotic pressure
T/F: During daily activity (daytime) fluid exits the disc resulting disc space narrowing and a loss of seated height of about 40mm.
False; 20mm
What happens to lumbar flexion ROM as the disc space narrows throughout the day?
lumbar flexion increases up to 50%
