A thoracic surgeon removed the right middle lobar (secondary) bronchus along with lung tissue from a 57-year-old heavy smoker with lung cancer. Which of the following bronchopulmonary segments must contain cancerous tissues?,

**Core Concept**
The bronchopulmonary segments are the functional units of the lung, each supplied by a specific bronchus. The right middle lobe (RML) is divided into two segments: the superior segment (S) and the middle segment (M). Understanding the anatomy of the bronchopulmonary segments is crucial for identifying the affected area in lung surgery.

**Why the Correct Answer is Right**
When the right middle lobar (secondary) bronchus is removed, the segments that were supplied by this bronchus will be affected. The superior and middle segments of the right middle lobe are the primary segments supplied by the right middle lobar bronchus. Since the bronchus was removed, both segments will be affected, and cancerous tissues must be present in both.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not specified, so we can't evaluate it.
* **Option B:** This option is not specified, so we can't evaluate it.
* **Option C:** This option is not specified, so we can't evaluate it.
* **Option D:** This option is not specified, so we can't evaluate it.

**Clinical Pearl / High-Yield Fact**
In thoracic surgery, the bronchopulmonary segments are the key to understanding lung anatomy and identifying the affected areas. The surgeon must be aware of the segmental anatomy to ensure complete removal of the tumor and minimize damage to surrounding healthy tissue.

**Correct Answer:** .

✓ Correct Answer: A. Medial and lateral