Question

Case 1:   Individuals with a history of herniated disc are usually advised against lifting/carrying a large load held out in front of the body, especially with a flexed lumbar spine.

1.      Describe the presentation of the disc when the spine segments are flexed (see image below for reference).

2. Using your knowledge of biomechanics gained this summer, explain why lifting/carrying a load in the front of the body would place a patient at risk for further lumbar disc pathology.

Answer 1

ANSWER :

a)When spine segments are flexed :

• Internal pressure on a disc increases
• Anterior aspect of the disc is compressed and the nucleus pulposus gets pressed against annulus fibrosis on the poterior side of the disc and posterior aspect of the intervertebral space opens up.
• So, disc bulges posteriorly into the spinal canal.

b)Lifting or carrying a load in front of the body leads to :

• Flexion of the spine which leads to increase in internal disc pressure from 17psi to 300 psi .
• During flexion when annulus pulposus presses and stretches tightly over the annulus fibrosis , which becomes thinned and gets ruptured through which the contents will flow into spinal canal and leads to compression of spinal cord or nerve roots which causes risk for further disc pathology.
• So it is better not to do activities associated with spinal cord flexion.