The Trunk

Question 1

Which vertebral ligaments bear load while the trunk is fully flexed?

Answer 1

Lumbar ligaments

Question 2

What happens to the nucleus and annulus of the intervertebral discs during compressive loading? (Make sure you understand the structure and function of the disc and its components).

Answer 2

• During compressive loading, hydrostatic pressure develops within the NP, which thereby disperses the forces towards the endplates as well as the AF
• Can cause NP to migrate under pressure

Question 3

3. What is the influence of posture on disc pressure? (Make sure you understand the impact of standing, lying, sitting, sitting upright & sitting in flexion).

Answer 3

• hanging from a standing to a sitting position makes the top of the pelvis rotate backwards. This flattens the natural lumbar curve of the spine, causing an increased uneven pressure on the intervertebral discs.
• Slouching can cause the spinal ligaments to stretch beyond their healthy limit, and poor posture can strain your spinal discs.

Question 4

5. What muscles are responsible for flexion, lateral flexion and extension of the trunk? (Make sure you are aware of the examples of helping synergy that occur in these movements).

Answer 4

• Lateral flexion: internal oblique, erector spinae, rectus abdominis
• Extension: Erector Spinae
• Flexion: Rectus abdominis, internal and external oblique

Question 5

10. Why is it not a good idea to load the vertebral column heavily soon after waking?

Answer 5

Sleep Inertia