Question

Parts of the great colon in horses, starting from cranial to caudal are
(A). Left ventral colon
(B). Right ventral colon
(C). Left dorsal colon
(D). Right dorsal colon
Choose the correct answer from the options given below:

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

Hint:

To remember the flow of the equine large colon, trace it in a circular shape:
Start on the right floor (RV), cross to the left floor (LV), loop up at the pelvic flexure to the left ceiling (LD), and cross to the right ceiling (RD).
This gives the sequence RV $\rightarrow$ LV $\rightarrow$ LD $\rightarrow$ RD.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The great colon (large colon) of the horse is an extremely large, double-folded loop that fills a major portion of the abdominal cavity.
It has a highly characteristic anatomy consisting of four distinct segments connected by three flexures.

Step 2: Detailed Explanation:
Let us follow the anatomical flow of digesta through the great colon, starting from its origin at the cecum (cranial/proximal) to its termination:
1. Right Ventral Colon (RVC) (B): Begins at the cecocolic orifice in the right dorsal abdomen and runs cranially along the right abdominal floor.
2. Sternal Flexure: The RVC turns left at the diaphragm to become the LVC.
3. Left Ventral Colon (LVC) (A): Runs caudally along the left abdominal floor toward the pelvis.
4. Pelvic Flexure: Near the pelvic inlet, the colon makes a sharp 180-degree turn dorsally and narrows significantly to become the LDC. (This is a common site for impactions).
5. Left Dorsal Colon (LDC) (C): Runs cranially along the left dorsal abdomen.
6. Diaphragmatic Flexure: The LDC turns right at the diaphragm to become the RDC.
7. Right Dorsal Colon (RDC) (D): Runs caudally along the right dorsal abdomen and is the widest part before narrowing into the transverse colon.
Thus, the correct sequence from cranial/proximal to caudal/distal is:
Right Ventral (B) $\rightarrow$ Left Ventral (A) $\rightarrow$ Left Dorsal (C) $\rightarrow$ Right Dorsal (D).

Step 3: Final Answer:
This sequence matches (B), (A), (C), (D), which corresponds to option (D).