Question

Spiral colon is characteristic of

• A. (A) and (D) only.
• B. (A), (B) and (D) only.
• C. (A), (B), (C) and (D).
• D. (A) and (C) only.

Hint:

Remember that the spiral colon is a hallmark of artiodactyls (even-toed ungulates), which includes ruminants (ox) and non-ruminant artiodactyls (pig).
Perissodactyls (horses) and carnivores (dogs) do not have a spiral colon.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The mammalian large intestine exhibits significant anatomical variation adapted to dietary patterns.
In certain species, the ascending colon is highly modified into a spiral arrangement (ansa spiralis) to maximize water absorption and fermentation.

Step 2: Detailed Explanation:
Ruminants (such as the ox) and pigs possess a highly characteristic spiral colon.
In the ox, the ascending colon forms a flat, disc-like spiral (ansa spiralis) consisting of centripetal (inward) and centrifugal (outward) coils situated in the right flank.
In the pig, the spiral colon is arranged as a three-dimensional cone, where the centripetal coils form the outer part of the cone and the centrifugal coils form the inner core.
In contrast, carnivores like dogs have a simple, short, U-shaped colon consisting of ascending, transverse, and descending segments without any spiral loops.
Equines (horses) have a massive, double-folded colon (great colon) with diaphragmatic and pelvic flexures, but it does not form a spiral colon.
Therefore, the spiral colon is a characteristic anatomical feature of the ox and the pig.

Step 3: Final Answer:
Thus, the correct options are (A) and (C) only, which corresponds to option (D).