Which of the following structures is involved in the muscular components of the diaphragm?

Which of the following structures is involved in the muscular components of the diaphragm?

• A. Septum transversum
• B. Pleuroperitoneal membranes
• C. Cervical somites C5-7
• D. Costal arch

Answer: (C)

The diaphragm's muscular components are primarily derived from the cervical somites, specifically those corresponding to levels C3, C4, and C5, which contribute to the phrenic nerve. This nerve is crucial for diaphragm innervation and allows for the muscle's contraction during respiration. The diaphragm is continuously active during inhalation and plays a significant role in ventilatory mechanics, with its components developing from these cervical origins. In contrast, while the septum transversum plays a role in the diaphragm's development, it primarily contributes to the formation of the central tendon rather than the muscular components. Similarly, the pleuroperitoneal membranes are critical for separating the thoracic and abdominal cavities during development but do not form the muscle itself. The costal arch relates to the bony structure of the thoracic wall and does not have a direct role in forming the muscular components of the diaphragm. Therefore, the involvement of cervical somites C5-7 specifically highlights the importance of these structures in ensuring the diaphragm's proper function.

The diaphragm's muscular components are primarily derived from the cervical somites, specifically those corresponding to levels C3, C4, and C5, which contribute to the phrenic nerve. This nerve is crucial for diaphragm innervation and allows for the muscle's contraction during respiration. The diaphragm is continuously active during inhalation and plays a significant role in ventilatory mechanics, with its components developing from these cervical origins.

In contrast, while the septum transversum plays a role in the diaphragm's development, it primarily contributes to the formation of the central tendon rather than the muscular components. Similarly, the pleuroperitoneal membranes are critical for separating the thoracic and abdominal cavities during development but do not form the muscle itself. The costal arch relates to the bony structure of the thoracic wall and does not have a direct role in forming the muscular components of the diaphragm. Therefore, the involvement of cervical somites C5-7 specifically highlights the importance of these structures in ensuring the diaphragm's proper function.