True statement among the following regarding diaphragm is
**Core Concept**
The diaphragm is a dome-shaped muscle that separates the chest cavity from the abdominal cavity, playing a crucial role in breathing. It is the primary muscle of inspiration, contracting to increase the volume of the thoracic cavity and draw air into the lungs.
**Why the Correct Answer is Right**
During inspiration, the diaphragm contracts and descends, increasing the volume of the thoracic cavity and reducing intrathoracic pressure. This creates a pressure gradient that allows air to flow into the lungs through the trachea. The diaphragm's contraction also increases the volume of the pleural space, allowing the lungs to expand and fill with air. This process is facilitated by the openings in the diaphragm, including the aortic hiatus, esophageal hiatus, and peripheral openings that allow nerves and blood vessels to pass through.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the primary function of the diaphragm.
**Option B:** This option is incorrect because it does not specify the correct relationship between the diaphragm and the abdominal cavity.
**Option C:** This option is incorrect because it does not accurately describe the role of the diaphragm in breathing.
**Clinical Pearl / High-Yield Fact**
The diaphragm is innervated by the phrenic nerve, which arises from the cervical spine (C3-C5). Damage to the phrenic nerve can result in diaphragmatic paralysis, leading to impaired breathing and respiratory failure.
**Correct Answer: C.**