The part of anatomy that internally divides the thoracic cavity from the abdominal cavity is the

A. mediastinum

B. umbilicus

C. viscera

D. diaphragm.

The diaphragm is the part of anatomy that internally divides the thoracic cavity from the abdominal cavity. It separates the thoracic cavity, that where the heart and the lungs is located, from the abdominal cavity that contains many organs such as the stomach, liver, gallbladder and kidneys.