Question

The rotation of trunk is produced by:
(A) Combined action of external oblique with opposite internal oblique
(B) Contraction of both muscles
(C) Rectus abdominis with opposite external oblique
(D) Transversus abdominis
Choose the most appropriate answer from the options given below:

• (A) only
• (A) and (B) only
• (B) and (C) only
• (C) only

Hint:

Think external + opposite internal oblique for trunk rotation — rectus and transversus don’t rotate!

Answer 1

The Correct Option is A

The primary muscles responsible for rotation of the trunk are the external oblique and the opposite side internal oblique.
The external oblique on one side works with the internal oblique on the opposite side to produce rotational movement.
For example, the right external oblique and left internal oblique rotate the trunk to the left.
The rectus abdominis is involved in trunk flexion, not rotation.
Transversus abdominis mainly compresses abdominal contents but does not contribute to rotation.
So only option (A) correctly describes the action that produces trunk rotation.