the thoracic cavity is _____to the abdominal cavity
The thoracic cavity is separated from the abdominal cavity by the  diaphragm. This is a broad flat muscle.    (muscular) diaphragm The diaphragm is a muscle that separatâ¦e the thoracic from the abdominal cavity. The pelvis is the lowest part of the abdominal cavity and it has no physical separation from it    Diaphragm.