Conference 2: Back 2

Question 1

Feature #1

Answer 1

Spinous proess

Question 2

Feature #2

Answer 2

Pedicles

Question 3

Feature #3

Answer 3

Laminae

Question 4

Indicated by yellow lines

Answer 4

Interlaminar space

Question 5

Anatomical features that make the lower lumbar spine best place for spinal tap:

Answer 5

1. spinal cord ends at L2 but the subarachnoid space goes until S1 or S2
2. lumbar spinous processes don’t overlap
3. large interlaminar space

Question 6

T1 weighted MRIs

Answer 6

Fat produces high signal (appears white), water appears dark

Question 7

T2 weighted MRIs

Answer 7

Water produces high signal and appears white

Question 8

How does the anatomy of the L4-L5 disc differ from the normal discs located just above and below it ?

Answer 8

1. reduced disc height
2. reduced fluid content
3. posterior herniation

Question 9

What forces would act on the disc during flexion of the spine?

Answer 9

• Tensile stress: on posterior part of disc (red)
• Compression forces on anterior part of disc (blue)

Question 10

What anatomic factors predispose intervertebral discs to posterolateral herniations during spine flexion?

Answer 10

1. no (weak) posterolateral ligament support (when compared to anteromedial)
2. annulus fibrosis is thinner posteriorly
3. eccentric position of nucleus pulposus
4. flexion puts more tensile stress on posterior part of disc

Question 11

Why is a tumor compressing the spinal cord at the T11 vertebral level causing pain in the upper lumbar region and not in the lower thoracic region?

Answer 11

Spinal cord segments for the upper lumbar spinal nerves are located at the T11 vertebral level