Question 1

Q: Constrictions in the esophagus are seen at all of the following levels EXCEPT:

The level of the thoracic duct crossing. The esophagus is a muscular tube approximately 25 cm long that exhibits four physiological constrictions. These are sites where the lumen is narrowed, making them clinically significant for the passage of endoscopes and common sites for the lodgment of foreign bodies or corrosive injuries. ### **Explanation of Options** * **Option D (Correct):** The **thoracic duct** crosses from the right side to the left side behind the esophagus at the level of the **T5 vertebra**. While it is in close proximity, it does not cause a physiological narrowing or indentation of the esophageal lumen. [2] * **Option A (Incorrect):** The first constriction occurs at the **pharyngoesophageal junction** (C6 level), caused by the cricopharyngeus muscle. This is the narrowest part of the entire esophagus. * **Option B (Incorrect):** The second constriction is caused by the **arch of the aorta** crossing the anterior surface of the esophagus (T4 level). A third constriction often occurs just below this, where the **left main bronchus** crosses (T5 level). * **Option C (Incorrect):** The final constriction occurs at the **esophageal hiatus** (T10 level), where the esophagus pierces the diaphragm to enter the abdominal cavity. [1] ### **High-Yield NEET-PG Pearls** * **Distance from Incisor Teeth:** 1. Cricopharyngeal sphincter: **15 cm** 2. Aortic arch/Left bronchus: **25 cm** 3. Diaphragmatic opening: **40 cm** * **Clinical Significance:** These sites are the most common locations for **esophageal strictures** following corrosive ingestion and are the most frequent sites for **impacted foreign bodies**. * **Muscle Composition:** The upper 1/3 is skeletal muscle, the middle 1/3 is mixed, and the lower 1/3 is smooth muscle.

Question

Constrictions in the esophagus are seen at all of the following levels EXCEPT:

Accepted Answer

The level of the thoracic duct crossing

Answer

The pharyngoesophageal junction

Answer

The level of the aortic arch crossing

Answer

The level where the esophagus pierces the diaphragm

Thorax — MCQs

Thorax — MCQs

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