The diaphragm is the muscular wall that separates the thorax from the abdomen regions. The diaphragm, which is dome-shaped and extends across the rib cage's bottom, is made up of the peripheral muscle and central tendon.
The diaphragm also has openings that allow for the passage of anatomical structures like the esophagus, descending aorta, vagus nerve and the inferior vena cava. A main function of the diaphragm is to aid respiration. When the diaphragm contracts, it causes an expansion of the lungs as air is breathed in. A diaphragm impairment can cause breathing problems, as stated by MedicineNet.
The thoracic cavity contains the esophagus, heart, bronchi and lungs. The abdominal cavity consists of organs that include the stomach, liver, spleen and pancreas.