Which statement best describes the primary function of the sacroiliac joints?

Which statement best describes the primary function of the sacroiliac joints?

• A. Bear the weight of the upper body
• B. Provide extensive rotational movement for gait
• C. Allow large flexion-extension of the spine
• D. Enclose the spinal cord

Answer: (A)

The main idea here is weight transfer. The sacroiliac joints are the connection between the spine and the pelvis, built to move and transmit the trunk’s load down into the pelvis and then into the legs. They’re designed for stability, not large amounts of motion, so they allow only small movements (tiny gliding and nutation/counternutation) to absorb forces during walking. That makes bearing the weight of the upper body their primary role. Rotational movement at these joints isn’t extensive and isn’t the main function, large flexion-extension of the spine is handled by the spinal column itself, and the spinal cord is enclosed within the vertebral canal, not by the sacroiliac joints.

The main idea here is weight transfer. The sacroiliac joints are the connection between the spine and the pelvis, built to move and transmit the trunk’s load down into the pelvis and then into the legs. They’re designed for stability, not large amounts of motion, so they allow only small movements (tiny gliding and nutation/counternutation) to absorb forces during walking. That makes bearing the weight of the upper body their primary role.

Rotational movement at these joints isn’t extensive and isn’t the main function, large flexion-extension of the spine is handled by the spinal column itself, and the spinal cord is enclosed within the vertebral canal, not by the sacroiliac joints.