Question

All of the following are branches of the inferior mesenteric artery except:

• A. Left colic artery
• B. Sigmoidal artery
• C. Middle rectal artery
• D. Superior rectal artery

Hint:

Which rectal artery comes from the internal iliac, not the IMA?

Answer 1

The Correct Option is C

Step 1: Branches of the inferior mesenteric artery (IMA). The IMA gives off the left colic artery (which divides into ascending and descending branches), the sigmoidal arteries (2 to 3, supplying the descending and sigmoid colon), and the superior rectal artery, which is the terminal continuation of the IMA into the lesser pelvis.

Step 2: Origin of the middle rectal artery. The middle rectal artery is a branch of the internal iliac artery, not the IMA. It anastomoses with the superior rectal artery in the rectal wall but does not arise from the IMA.

Step 3: Eliminate the others. Left colic, sigmoidal, and superior rectal arteries all arise from the IMA, so options (a), (b) and (d) are true branches.

Step 4: Conclusion. The middle rectal artery is the exception, so the correct answer is option (c).