Body Cavities


 The thing about a cavity search is this: it has nothing to do with the dentist. Anon.


Body cavities are spaces in our bodies that contain organs.  Organs are inside these cavities for protection, and the cavity allows the organs to change shape (our lungs, stomachs and bladders all need to expand and contract).  The video illustrates the major cavities, and it is followed by a listing of all of the cavities we'll be talking about  in our class. 

  • Cranial cavity: Contains the brain.

  • Spinal cavity: Contains the spinal cord, which is an extension of the brain.

List identifing cavities and subcavities of the human body:


  • Dorsal cavity: Bones of the cranial portion of the skull and vertebral column, toward the dorsal (posterior) side of the body.

  • Ventral cavity: Anterior surface of torso; divided by diaphragm muscle into upper thoracic cavity and abdominopelvic cavity.

The Dorsal Cavity is divided into two subsections.

The Cranial Cavity contains the brain.

The Spinal Cavity contains the Spinal Chord.






The Thorasic Cavity (The chest) contains the trachea, bronchi, lungs, esophagus, heart and great blood vessels, thymus gland, lymph nodes, and nerves. It is divided into smaller cavities, too:


The Diaphragm is a muscle that divides the Dorsal Cavity.



The Abdominal Cavity Contains the stomach, liver, spleen, gallbladder, pancreas, , kidneys, and intestines (small and large), and ovaries (in female)

The Pelvic Cavity Contains the colon, rectum, urinary bladder, uterus (in females)

The Ventral Cavity is divided into subsections.

Thorasic Cavities

  • The Thoracic Cavity is subdivided into Pleural (Pleural = Lungs) cavities, the mediastinum, and the pericardial (Cardiac = Heart) cavity


  • There are two Pleural Cavities, each houses a lung


  • The Mediastinum contains the pericardial cavity, and surrounds the remaining thoracic organs


  • The Pericardial Cavity encloses the heart

Ventral body Cavities are lined with Membranes.

  • Parietal serosa lines internal body walls


  • Visceral serosa covers the internal organs


  • Serous fluid separates the serosae

Let's imagine what this looks like.  We can use a water balloon to make a model of this (to help us understand and visualize the concepts here).

Water - analogous to the Serous Fluid.

Inner Balloon Wall - analogous to the Visceral Serosa.

Outer Balloon Wall - analogous to the Parietal Serosa.

We can compare the model at the right with the real life illustration to the left to better grasp the serosa and its structure.

Other Cavities

  • Oral – mouth

  • Digestive –cavities of the digestive organs

  • Nasal –located within and posterior to the nose

  • Orbital – house the eyes

  • Middle ear – contain bones (ossicles) that transmit sound vibrations

  • Synovial – joint cavities

Abdominopelvic Regions

Take careful note of the location of each of these regions, along with their names.  There is a logic used here - see if you can figure it out.

  • Umbilical

  • Epigastric

  • Hypogastric

  • Right and left iliac or inguinal

  • Right and left lumbar

  • Right and left hypochondriac

Organs of the Abdominopelvic Regions.

Abdominopelvic Quadrants

This is material you need to know - there is no use in complaining about it. 

Memorize this material and be done.