Pleural tapping in the mid-axillary line, muscle not pierced is
**Core Concept**
The question tests the student's knowledge of the anatomy of the intercostal spaces, specifically the location of the intercostal muscles in relation to the pleural space. The intercostal muscles, including the external, internal, and innermost intercostal muscles, are located between the ribs and play a crucial role in respiration.
**Why the Correct Answer is Right**
When performing a pleural tap in the mid-axillary line, the needle must be inserted between the ribs to avoid piercing any of the intercostal muscles. The correct answer is the muscle that is not pierced during this procedure. The external intercostal muscle is the outermost of the intercostal muscles and is not pierced during pleural tapping in the mid-axillary line. This is because the needle is inserted between the ribs, and the external intercostal muscle is located on the anterior surface of the ribs.
**Why Each Wrong Option is Incorrect**
**Option A:** The internal intercostal muscle is a potential space-occupying structure that could be pierced during pleural tapping, making it an incorrect answer.
**Option B:** The innermost intercostal muscle is a thin layer of muscle fibers located between the internal intercostal muscle and the endothoracic fascia, which could be pierced during pleural tapping, making it an incorrect answer.
**Option C:** The serratus anterior muscle is a muscle located in the lateral thoracic wall and is not directly related to the intercostal spaces, making it an incorrect answer.
**Clinical Pearl / High-Yield Fact**
When performing a pleural tap, it is essential to insert the needle between the ribs to avoid piercing any of the intercostal muscles, which can lead to complications such as bleeding or pneumothorax.
**Correct Answer:** A. External intercostal muscle.