In cats, what portion of the esophagus is skeletal muscle?

• A. Cranial 2/3 (caudal 1/3 is smooth muscle)
• B. Cranial 1/3
• C. Caudal 2/3
• D. Whole esophagus

Answer: (A)

The main idea here is that the esophagus in cats contains both skeletal and smooth muscle, with a distinct regional split that matches how swallowing is controlled. The proximal portion is skeletal muscle, and the distal portion is smooth muscle. In cats, the cranial two-thirds of the esophagus are skeletal muscle, while the caudal one-third is smooth muscle. This setup lets you initiate swallowing voluntarily, then rely on automatic, rhythmic peristalsis to move the bolus downward.

So the portion that is skeletal muscle is the cranial two-thirds of the esophagus. The remaining distal third is smooth muscle, and the whole esophagus is not composed solely of skeletal muscle.