Which statement about the rectus abdominis is true?

Which statement about the rectus abdominis is true?

• A. It laterally flexes the spine
• B. It extends the spine
• C. It flexes the vertebral column
• D. It rotates the pelvis

Answer: (C)

The primary action of the rectus abdominis is to flex the vertebral column. When both sides contract together, they pull the upper body toward the pelvis, producing trunk flexion as seen in a curl-up or sit-up. This muscle also helps compress the abdomen, stabilizing the trunk. It does not extend the spine — that motion is carried out by the back extensor muscles, like the erector spinae, especially when you bend forward and then straighten up. It also doesn’t rotate the pelvis; that action is mainly produced by the obliques and other hip/pelvic rotators. So the statement that it flexes the vertebral column is the correct one.

The primary action of the rectus abdominis is to flex the vertebral column. When both sides contract together, they pull the upper body toward the pelvis, producing trunk flexion as seen in a curl-up or sit-up. This muscle also helps compress the abdomen, stabilizing the trunk.

It does not extend the spine — that motion is carried out by the back extensor muscles, like the erector spinae, especially when you bend forward and then straighten up. It also doesn’t rotate the pelvis; that action is mainly produced by the obliques and other hip/pelvic rotators. So the statement that it flexes the vertebral column is the correct one.