Which muscles are the primary trunk flexors, aided by the obliques?

Which muscles are the primary trunk flexors, aided by the obliques?

• A. Rectus Abdominis is the primary trunk flexor, aided by the external and internal obliques
• B. Erector Spinae
• C. Latissimus Dorsi
• D. Transverse Abdominis

Answer: (A)

Trunk flexion is produced mainly by the rectus abdominis, a vertical muscle along the front of the abdomen. When it shortens, it pulls the rib cage toward the pelvis, curling the torso forward. The external and internal obliques sit on the sides and assist in flexion when both sides contract, while also enabling rotation and lateral bending. They support and augment the movement rather than being the primary movers. The other muscles listed don’t flex the trunk primarily: the erector spinae extends the spine; the latissimus dorsi mainly moves the arms and stabilizes the trunk; and the transverse abdominis stabilizes the abdomen and spine rather than producing flexion.

Trunk flexion is produced mainly by the rectus abdominis, a vertical muscle along the front of the abdomen. When it shortens, it pulls the rib cage toward the pelvis, curling the torso forward. The external and internal obliques sit on the sides and assist in flexion when both sides contract, while also enabling rotation and lateral bending. They support and augment the movement rather than being the primary movers. The other muscles listed don’t flex the trunk primarily: the erector spinae extends the spine; the latissimus dorsi mainly moves the arms and stabilizes the trunk; and the transverse abdominis stabilizes the abdomen and spine rather than producing flexion.