Subpectoral abscess can be caused by which of the following?

Subpectoral abscess can be caused by which of the following?

• A. Suppurative adenitis of axillary lymph nodes, rib or pleural infection, or posterior extension of a breast abscess, complication of chest wall surgery
• B. Pneumonia and bronchitis
• C. Pulmonary embolism
• D. Gastric ulcer

Answer: (A)

Subpectoral abscess forms when infection spreads into the space beneath the pectoralis major from nearby chest wall structures. Infections of the axillary region, such as suppurative adenitis of axillary lymph nodes, can extend posteriorly into the subpectoral space. Likewise, infection of the ribs or pleura can track into this area, and a breast abscess that extends backward can drain into or form an abscess beneath the pectoralis muscle. Chest wall surgery can also disrupt tissue planes and create a nidus for infection in this space. These routes show local, contiguous spread into the subpectoral plane, which is the characteristic mechanism. In contrast, pneumonia and bronchitis involve the lungs, not the subpectoral space; a pulmonary embolism is a vascular event without abscess formation; and a gastric ulcer is unrelated anatomically to the chest wall compartments. Therefore, the described local infectious pathways best explain a subpectoral abscess.

Subpectoral abscess forms when infection spreads into the space beneath the pectoralis major from nearby chest wall structures. Infections of the axillary region, such as suppurative adenitis of axillary lymph nodes, can extend posteriorly into the subpectoral space. Likewise, infection of the ribs or pleura can track into this area, and a breast abscess that extends backward can drain into or form an abscess beneath the pectoralis muscle. Chest wall surgery can also disrupt tissue planes and create a nidus for infection in this space. These routes show local, contiguous spread into the subpectoral plane, which is the characteristic mechanism.

In contrast, pneumonia and bronchitis involve the lungs, not the subpectoral space; a pulmonary embolism is a vascular event without abscess formation; and a gastric ulcer is unrelated anatomically to the chest wall compartments. Therefore, the described local infectious pathways best explain a subpectoral abscess.