Body Cavities

Diaphragm

A dome-shaped muscle that separates the thoracic cavity from the abdominopelvic cavity.

Mediastinum

Central portion of thoracic cavity between the medial walls of pleural cavities; extends from sternum to vertebral column and from first rib to diaphragm; contains *heart*, *thymus*, *esophagus*, *trachea* and *several large blood vessels*.

Thoracic cavity

Chest cavity; contains pleural and pericardial cavities and mediastinum. Encircled by *ribs*, *muscles of the chest*, the *sternum* (breastbone), and the thoracic portion of the vertebral column (*backbone*).

Abdominal cavity

Contains *stomach*, *spleen*, *liver*, *gallbladder*, *small intestine* and *most of large intestine*; the serous membrane of the abdominal cavity is the peritoneum.

Pelvic cavity

Contains *urinary bladder*, *portions of large intestine* and *internal organs of reproduction*.

Pleural cavity

Each surrounds a *lung*; the serous membrane of the pleural cavities is the pleura.

Cranial cavity

Formed by cranial bones and contains *brain*.

Vertebral canal

Formed by vertebral column and contains *spinal cord* and beginnings of *spinal nerves*.

Abdominopelvic cavity

Subdivided into abdominal and pelvic cavities.

Pericardial cavity

Surrounds the *heart*; the serous membrane of the pericardial cavity is the pericardium.