Certified Cardiovascular Technician Practice Exam

What anatomical landmark helps locate the 4th intercostal space?

1. Clavicle

2. Xiphoid process

3. Angle of Louis

4. Coracoid process

The correct answer is: Angle of Louis

The anatomical landmark that assists in locating the 4th intercostal space is the Angle of Louis, also known as the sternal angle. This bony prominence is formed at the junction between the manubrium and the body of the sternum. It serves as a key reference point in anatomy because it is located at the level of the second rib, making it a reliable starting point for counting ribs and intercostal spaces. From this point, you can easily determine the location of the 4th intercostal space by counting down. The 2nd rib is attached at the Angle of Louis, and proceeding downward, the 3rd rib follows, leading to the 4th rib and its respective intercostal space. This systematic counting is utilized in clinical assessments, such as when auscultating the heart or examining structures within the thoracic cavity. In contrast, the other choices do not provide a clear or readily identifiable reference for locating the 4th intercostal space. The clavicle is positioned above the rib cage and does not correlate as directly with intercostal spaces. The xiphoid process is located at the inferior end of the sternum and is not helpful for this specific level. The corac