**Question:** When Pleural tapping is done in the mid axillary line, muscle not pierced is -

A. Latissimus dorsi
B. Serratus anterior
C. Subscapularis
D. Rhomboid major

**Core Concept:**

Pleural tapping, also known as thoracentesis, is a procedure used to collect fluid from the pleural space for analysis or to relieve pleural effusion symptoms. In this context, we need to identify the muscle that is not pierced when performing the procedure in the mid axillary line.

**Why the Correct Answer is Right:**

In the mid axillary line, the correct puncture point is located between the fourth and fifth ribs. The pleural space lies between the parietal pleura (outer layer) and the visceral pleura (inner layer). When performing the procedure, the needle should not pierce through the muscle layers but rather enter the pleural space.

**Why Each Wrong Option is Incorrect:**

1. **Latissimus dorsi (Option A)**: The latissimus dorsi is a large, fan-shaped muscle located in the posterior aspect of the thoracic wall, which is not involved in the mid axillary line puncture for pleural tapping.

2. **Serratus anterior (Option B)**: The serratus anterior is a large, fan-shaped muscle located inferior to the latissimus dorsi. It is not pierced during a mid axillary line pleural tapping, making it an incorrect choice.

3. **Subscapularis (Option C)**: The subscapularis is a small, triangular muscle located inferior to the serratus anterior. It is not the muscle pierced while performing pleural tapping in the mid axillary line, making it an incorrect choice.

4. **Rhomboid major (Option D)**: The rhomboid major is a small, trapezoidal muscle located on the posterior aspect of the thoracic wall. It is not involved in the mid axillary line puncture for pleural tapping, making it an incorrect choice.

**Clinical Pearl:**

When performing pleural tapping in the mid axillary line, the most important aspect is to ensure that the needle enters the pleural space between the fourth and fifth ribs, avoiding the muscles located in the posterior aspect of the thoracic wall. This ensures a successful and safe procedure without complications.

**Explanation of correct answer:**

The correct answer is **serratus posterior superior (Option B)**. In the mid axillary line, the needle should be directed towards the fourth or fifth rib to enter the pleural space. The serratus posterior superior is a large, triangular muscle located superior to the serratus anterior. It is not an option to be avoided during pleural tapping, making it the correct answer.