**Question:** A 20 year old male was brought to the emergency department after he suffered a stab wound in the anterior chest wall. CT scan revealed aerial extravasation from injury to the internal thoracic artery. The condition causes a decrease in blood supply through all of the following blood vessels, except

A. Subclavian artery
B. Carotid artery
C. Renal artery
D. Coronary artery

**Correct Answer:**

**Core Concept:** The internal thoracic artery (ITA) is a branch of the subclavian artery, supplying blood to the anterior chest wall, axilla, and the first and second intercostal nerves. Injuries to the ITA can lead to bleeding and decreased blood supply to the affected area. However, the other given options are not branches of the subclavian artery and thus are not directly affected by ITA injury.

**Why the Correct Answer is Right:** The correct answer, D) Coronary artery, is not affected by injury to the internal thoracic artery because coronary arteries are branches of the left and right aortic arch, not the subclavian artery.

**Why Each Wrong Option is Incorrect:**

A) Subclavian artery: The internal thoracic artery is a branch of the subclavian artery, making it the correct answer and not one of the incorrect options.

B) Carotid artery: This artery supplies blood to the neck and head, not the anterior chest wall.

C) Renal artery: This artery supplies blood to the kidneys, not the anterior chest wall.

**Clinical Pearl:** Knowledge of the arterial supply to the chest wall is essential for understanding the potential consequences of injuries to specific arteries, such as the internal thoracic artery, in emergency medicine and trauma scenarios.