Question

According to the AAST (American Association for the Surgery of Trauma) Colon Injury Scale, a laceration involving more than 50% of the bowel circumference (without transection) corresponds to which grade?

• A. Grade I
• B. Grade II
• C. Grade III
• D. Grade IV

Hint:

Less than 50% circumference is Grade II; more than 50% (no transection) bumps it up one grade.

Answer 1

The Correct Option is C

The AAST colon scale runs by how much of the bowel wall is breached. Think of it as a ladder: partial-thickness or contusion sits at $I$, a laceration under half the circumference at $II$, a laceration over half the circumference at $III$, a clean transection at $IV$, and a transection with loss of tissue/blood supply at $V$.

Here the wound crosses more than 50% of the circumference yet the colon is not fully divided, so it stops at the over-half-circumference rung.

\[ \text{laceration} > 50\% \text{ circumference, no transection} \Rightarrow \text{Grade III} \]

\[\boxed{\text{Grade III}}\]