Final answer:
The diaphragm is a skeletal muscle separating the thoracic and abdominal cavities, featuring openings for the inferior vena cava, esophagus, aorta, thoracic duct, and azygous vein.
Step-by-step explanation:
The diaphragm is a crucial skeletal muscle that serves as a partition between the thoracic and abdominal cavities. It is dome-shaped at rest and facilitates important functions involving breathing and assisting in bodily processes such as defecating, urination, and childbirth. The diaphragm features three major openings that allow for the passage of structures:
- The caval opening, permitting the passage of the inferior vena cava.
- The esophageal hiatus, through which the esophagus and attached nerves pass.
- The aortic hiatus of the posterior diaphragm, where the aorta, thoracic duct, and azygous vein travel.
These structures are essential for bodily functions and maintaining internal homeostasis.