Herniated Nucleus Pulposus Flashcards
Comprises the cartilaginous joint between adjacent vertebral bodies
-allows for mobility between adjacent vertebrae
Intervertebral disk
The intervertebral disk functions as a
Shock absorber
The outer portion of the intervertebral disk
Anulus fibrosis
Composed of rings of fibrocartilage and fibrous connective tissue with a high collagen content
Anulus fibrosis
The inner portion of the intervertebral disk is the
Nucleus pulposus
Gelatinous in character, contains few cells, and is rich in proteoglycans
Nucleus pulposus
There is a high water content bound in the nucleus pulposus, and this provides
Turgor (rigidity) to the disk
Serves the function of distributing pressure throughout the disk when the vertebral column is weight bearing (i.e. upright posture)
Nucleus Pulposus
What happens when you are standing upright?
Water is squeezed out of nucleus and the nucleus gets thinner
When not weight bearing (i.e. when reclined), water returns to the nucleus and the disk gets
Thicker
The thinning of the nucleus from water loss due to upright posture explains why we are
Taller in the morning than at night
With age, there is a loss of proteoglycans in the nucleus pulposus and therefore the amount of bound water is
Reduced
The loss of proteoglycans, and therefore water, from the nucleus pulposus explains what phenomenon of aging?
We get shorter
The nucleus pulposus is not centrally positioned in the disk, but rather it is positioned towards the
Posterior side of disk
Thinner posteriorly than it is anteriorly because of position of nucleus pulposus
Anulus fibrosus
What can happen with degeneration of the anulus fibrosus and with pressure applied to the intervertebral disk during movement?
Anulus ruptures and nucleus pulposus can herniate through anulus
Because the anulus is thinner posteriorly and because flexion of the spine stretches the posterior portion of the anulus and squeezes the nucleus pulposus posteriorly, the nucleus is much more likely to herniate in a
Posterior direction
However, because the posterior midline of the disk is reinforced by the posterior longitudinal ligament, the nucleus is most likely to herniate in a
Posterolateral direction
This posterolateral herniation can result in impingement on the roots of spinal nerves in either the
Lateral portion of vertebral canal, or in intervertebral foramen
Compression of the spinal nerves (or spinal roots) may result in
Sensory/motor disturbance
The location of these clinical findings will be in regions of distribution of these spinal nerve fibers known as
Dermatomes (for sensory findings) and myatomes (for motor findings)
Formed by the apposition of adjacent intervertebral notches, i.e. the inferior notch of one vertebra with the superior notch of the next
Intervertebral foramen
Anteriorly, the borders of the intervertebral foramen are
Body of vertebra above, intervertebreal disk, and body of vertebra below
Posteriorly, the borders of the intervertebral foramen are the
Inferior articular facet of vertebra above, superior articular facet of vertebra below, and zygopophyseal joint