Which muscle subdivides the ventral body cavity by separating the thoracic cavity from the abdominopelvic cavity?

• A. External intercostal muscles
• B. Rectus abdominis
• C. Pectoralis major
• D. Diaphragm

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the anatomy of the ventral body cavity, which is divided into two main parts: the thoracic cavity (upper) and the abdominopelvic cavity (lower).
2. Step 2: Identify the muscle that acts as a physical barrier between these two cavities, playing a crucial role in respiration by contracting and relaxing to change thoracic volume.
3. Step 3: Recall that the diaphragm is a dome-shaped muscle located at the base of the thoracic cavity, separating it from the abdominopelvic cavity below.
4. Step 4: Recognize that other muscles listed, such as the external intercostal muscles, rectus abdominis, and pectoralis major, have different locations and functions and do not separate these two cavities.
5. Step 5: Conclude that the diaphragm is the muscle responsible for subdividing the ventral body cavity by separating the thoracic cavity from the abdominopelvic cavity.