**Question:** Patey's mastectomy involves removal of all of the following except -

A. **Skin and subcutaneous tissue only**
B. **Axillary lymph nodes**
C. **Musculocutaneous nerve and its branches**
D. **Scapular muscle attachment**

**Correct Answer: B. Axillary lymph nodes**

**Core Concept:** Patey's mastectomy is a surgical procedure primarily used for the treatment of breast cancer. This procedure involves the removal of the breast tissue, skin, subcutaneous tissue, and muscles, while preserving the skin and its blood supply, the nipple-areolar complex, and the pectoralis major muscle.

**Why the Correct Answer is Right:** In Patey's mastectomy, the primary goal is to remove the entire breast tissue and subcutaneous tissue, while preserving essential structures such as the skin, nipple-areolar complex, and pectoralis major muscle. The correct answer, **Axillary lymph nodes**, is not removed because they are part of the lymphatic system and serve as a crucial component in the body's immune defense against infections and malignancies.

**Why Each Wrong Option is Incorrect:**

A. **Skin and subcutaneous tissue only**: This option is incorrect as it does not account for the removal of the nipple-areolar complex, which is an essential part of the procedure and serves to preserve the patient's identity and appearance post-surgery.

C. **Musculocutaneous nerve and its branches**: This option is incorrect because the musculocutaneous nerve and its branches are crucial for sensation and motor function in the treated extremity. By preserving these nerves, the patient can regain sensation and movement in the treated area.

D. **Scapular muscle attachment**: This option is incorrect as the scapular muscle attachment is not a critical component of the procedure. Instead, the primary focus of Patey's mastectomy is to remove the breast tissue, subcutaneous tissue, and skin while preserving essential structures.

**Clinical Pearl:** In the context of breast cancer management, understanding the rationale behind the removal of specific structures during mastectomy procedures is crucial for the preservation of the patient's identity, appearance, and functional integrity. Patey's mastectomy aims to remove the breast tissue, subcutaneous tissue, and skin while preserving essential structures to ensure the patient's well-being and quality of life post-surgery.