Which muscles extend the trunk?

Which muscles extend the trunk?

• A. Latissimus Dorsi and Gluteus Maximus
• B. Erector Spinae Group (iliocostalis, longissimus, spinalis) and Multifidus
• C. Rectus Abdominis
• D. External Oblique

Answer: (B)

Extending the trunk means straightening the spine from a flexed or slouched position, which is produced mainly by muscles on the back that pull the vertebral column into extension. The primary players are the Erector Spinae group—iliocostalis, longissimus, and spinalis—which run along the spine and contract to straighten and extend the vertebral column, helping you stand tall. The Multifidus adds deeper stabilization and also contributes to extending the spine, especially during controlled or segmental movements. Muscles like the latissimus dorsi and gluteus maximus focus more on hip and shoulder movements, not direct trunk extension. The rectus abdominis and external oblique, on the other hand, are abdominal flexors that bend the trunk forward rather than extend it. So, the combination that best explains trunk extension is the Erector Spinae group along with the Multifidus.

Extending the trunk means straightening the spine from a flexed or slouched position, which is produced mainly by muscles on the back that pull the vertebral column into extension. The primary players are the Erector Spinae group—iliocostalis, longissimus, and spinalis—which run along the spine and contract to straighten and extend the vertebral column, helping you stand tall. The Multifidus adds deeper stabilization and also contributes to extending the spine, especially during controlled or segmental movements. Muscles like the latissimus dorsi and gluteus maximus focus more on hip and shoulder movements, not direct trunk extension. The rectus abdominis and external oblique, on the other hand, are abdominal flexors that bend the trunk forward rather than extend it. So, the combination that best explains trunk extension is the Erector Spinae group along with the Multifidus.