MSK: Spine

Question 1

describe the ligaments associated with the spine

Answer 1

1. ANTERIOR LONGITUDINAL LIGAMENT - prevents hyperextension
2. POSTERIOR LONGITUDINAL LIGAMENT - prevents hyperflexion
3. LIGAMENTUM FLAVUM - prevents hyperflexion
4. INTERSPINOUS LIGAMENT - stability in flexion
5. SUPRASPINOUS LIGAMENT - prevent hyperflexion

Question 2

where should LPs be performed?

Answer 2

L4/5 (top of iliac crest level) or L3/4, i.e. after cauda equina starts at L1/2 - only mobile spinal nerve roots so least chance of neurological damage.

Question 3

name the layers through which an LP needle passes

Answer 3

• skin
• subcutaneous tissue
• supraspinous ligament
• interspinous ligament
• ligamentum flavum (large ‘give’)
• epidural fat and veins
• dura mater
• arachnoid mater
• subarachnoid space

Question 4

describe the 4 degrees of disc herniation

Answer 4

1. DISC DEGENERATION: chemical changes associated with ageing cause discs to dehydrate
2. DISC PROLAPSE: protrusion of nucleus pulposus (e.g. bending down causing tear in annulus fibrosus) with slight impingement into spinal canal
3. DISC EXTRUSION: nucleus pulposus breaks through annulus fibrosus but remains within disc space
4. DISC SEQUESTRATION: nucleus pulposus separates from body of disc into spinal canal

Question 5

where do disc herniations typically occur? what are the 3 types?

Answer 5

• Most commonly at L4/5 or L5/S1.
• Types:
  
  • paracentral (96%)
  • far lateral (2%)
  • canal filling (2%) - large fragment comes out compressing whole of cauda equina - CES