Question

What is the effect of counternutation on the lumbar spine?

1) It increases the lordosis of the lumbar spine
2) It decreases the lordosis of the lumbar spine
3) It has no effect on the lordosis of the lumbar spine
4) Cannot be determined without further information

Answer 1

Counternutation decreases the lordosis of the lumbar spine by reducing the anterior curvature, which in turn reduces the shear forces on the lumbar vertebrae.

Step-by-step explanation:

The effect of counternutation on the lumbar spine is that it decreases the lordosis of the lumbar spine. Counternutation is a movement of the sacrum that involves a slight upward movement of the base of the sacrum. This movement can lead to a reduced curve in the lumbar region, which is the opposite of lordosis or swayback. Lordosis refers to an excessive anterior curvature of the lumbar region, which can be increased due to factors like obesity or pregnancy, leading to increased shear forces on the lumbar vertebrae and a higher risk of back injury. In counternutation, the decrease in lordosis reduces these shear forces. Thus, the correct answer to the student's question is: 2) It decreases the lordosis of the lumbar spine.