Intro to Anatomy 1: Life, Organization, and Terminology

Organization of the Human Body:

At its most basic level, the human body is organized into an axial portion and an appendicular portion. The axial portion of your body consists of your head, neck, and trunk. The appendicular portion consists of your limbs – your arms and legs.


Within the axial portion of the body are two large, membrane-lined cavities, the dorsal cavity and the ventral cavity. The dorsal cavity contains the central nervous system. The organs within the ventral cavity are collectively known as the viscera.




The dorsal cavity, as mentioned, contains the central nervous system – the brain and the spinal cord. The dorsal cavity is subdivided into the cranial cavity and the vertebral cavity. The cranial cavity is surrounded by the bones that make up the skull (or cranium), and contains the brain. The vertebral cavity (or spinal cavity) is surrounded by the bony vertebrae (the backbone), and contains the spinal cord.

The main body cavities. (Lateral view)

The ventral cavity is rather larger than is the dorsal cavity, and it, too, is subdivided into two smaller cavities – the thoracic cavity and the abdominopelvic cavity. The thoracic cavity and abdominopelvic cavity are separated from each other by a broad, thin sheet of muscle known as the diaphragm, which is important in breathing.


The thoracic cavity contains the heart, lungs, esophagus, trachea, and thymus gland. It is divided into right and left halves by a band of fat and other connective tissues called the mediastinum. Embedded in the mediastinum is the pericardial cavity, containing the heart. The thymus gland, esophagus, and trachea are also embedded in the mediastinum. Each lung is embedded in a pleural cavity, on either side of the mediastinum.



The abdominopelvic cavity is subdivided into the abdominal cavity and the pelvic cavity. The viscera found within the abdominal cavity include the stomach, liver, spleen, gallbladder, and kidneys. The pelvic cavity is that portion of the abdominopelvic cavity enclosed by the hip bones, and it contains portions of the large and small intestines, the urinary bladder, and the internal reproductive organs.

The main body cavities. (Anterior view)