Anatomy and Physiology: Anatomical Planes and Cavities

And here we are with part two of our rundown on the things you need to learn before you dive into the meaty stuff of A&P, specifically how to talk about the body. In our previous post, we discussed anatomical position and directional terms. In this post, we’re going to take a look at planes and cavities.


Planes: Because who said anatomy didn’t require an imagination?

No, not the kind that fly you over oceans and have helpful people in uniforms that ply you with bags of stale peanuts. The other kind! The art kind, or in more technical terms the area of a two-dimensional surface. When used in conjunction with anatomy, planes are used to divide the body and its parts, which allows you to describe the views from which you study the body. If you look at your A&P textbook, you’ll most likely notice that a good number of the pictures and diagrams make use of planes.

Here is a list of commonly used planes:

Frontal (Coronal) plane

Divides the body into anterior (front) and posterior (back) portions

Transverse plane

Divides the body into superior (upper) and inferior (lower) portions

Sagittal plane

Vertical plane that divides the body into right and left sides.

Midsagittal plane

Divides the body at midline into equal right and left sides.

Oblique plane

Divides the body at an angle.


Of course, in reality, the planes used are completely imaginary, but they are a helpful visual in terms of describing a view.

Want more information about anatomical planes? Check out our free Planes & Positions eBook! 

Frontal Plane Coronal Sagittal midline

Using a frontal plane to bisect the body lengthwise, we’re able to describe certain areas that would not be easily visible or accessible if we used another plane.

Transverse plane coronal frontal sagittal oblique

The transverse plane bisects the brain horizontally, allowing for a superior view.

 

Cavities: Because things need to be kept somewhere.

A concept easier to grasp than planes and directional is body cavities, as they are a physical thing. When you hear the word “cavity,” no doubt you think of the kind in your teeth that are caused by plaque. A cavity, in any capacity, is a hollow place. In your teeth, it’s a hollow bit in the hard body. In the body itself, it is a hollow place usually filled with organs, nerves, vessels, and muscles.

Here are the body’s cavities:

Cranial cavity

Formed by the cranial bones and holds the brain

Vertebral canal

Formed by the vertebrae and contains the spinal cord

Thoracic cavity

Formed by the thoracic cage, muscles of the chest, sternum, and the thoracic vertebrae; contains the pleural, pericardial, and mediastinum cavities

  • Pleural cavity

Fluid-filled spaces that surround both lungs

  • Pericardial cavity

Fluid-filled space that surrounds the heart; the serous membrane of the pericardial cavity is the pericardium

  • Mediastinum

Central portion of the thoracic cavity; contains the heart, thymus, trachea, several major blood vessels, and esophagus

Abdominal cavity

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

Pelvic cavity

Contains bladder, some of the large intestine, and reproductive organs (internal)

 cavities1The cranial cavity. Image from Human Anatomy Atlas.

cavities2The thoracic cavity. Image from Human Anatomy Atlas.

cavities3The abdominal cavity. Image from Human Anatomy Atlas.

cavities4The pelvic cavity. Image from Human Anatomy Atlas.


This post was originally published in 2013. It has since been updated with  new body cavity images from Human Anatomy Atlas 2019. 


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