Back Pain Back Pain Anatomy and Biomechanics

Question 1

Which spinal region is most commonly affected by back pain in the US adult population?

Accepted Answer

Lumbar

Answer

The lumbar region bears the most mechanical load and is the most frequent site of back pain in adults.

Question 2

What structure acts as a shock absorber between vertebral bodies?

Accepted Answer

Intervertebral disc

Answer

Intervertebral discs contain a nucleus pulposus and annulus fibrosus that absorb compressive forces between vertebrae.

Question 3

Which muscle group is considered the primary stabilizer of the lumbar spine?

Accepted Answer

Transversus abdominis

Answer

The transversus abdominis acts as a natural corset and is the deepest core muscle providing lumbar stabilization.

Question 4

The nucleus pulposus of an intervertebral disc is primarily composed of which substance?

Accepted Answer

Proteoglycans and water

Answer

The nucleus pulposus is a hydrophilic gel consisting mainly of proteoglycans (aggrecan) and water, giving it its shock-absorbing properties.

Question 5

Which spinal nerve roots are typically compressed in an L4-L5 disc herniation causing sciatica?

Accepted Answer

L4 or L5

Answer

An L4-L5 disc herniation most commonly compresses the L5 nerve root (posterolateral) or L4 root (far lateral).

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