Anatomical Position and Planes

Anatomical Position

Information

When anatomists or health professionals identify the location of a structure in the human body, they do so in reference to a body in anatomical position. That is, they figure out the location based on the assumption that the body is starting out in anatomical position.

Anatomical position for a human is when the human stands up, faces forward, has arms extended, and has palms facing out.

Drawing of a man and woman, both facing forward, with their palms facing out.

Figure 1-1. These two people are both in anatomical position.

When referencing a structure that is on one side of the body or the other, we use the terms “anatomical right” and “anatomical left.” Anatomical right means that the structure is on the side that a person in anatomical position would consider their right-hand side (not necessarily on the right of the viewer) and anatomical left means that the structure is the side that a person in anatomical position would consider their left-hand side (which likewise is not necessarily the left side of the viewer.)

 

Anatomical planes

Information

To view the interior of a body, we expose the organs and structures that are visible when that body is cut open along one of four commonly used sectional planes. These planes are the different directions a body is cut to reveal different views of its internal structures.

  • Frontal plane—A vertical cut that separates the front from the back of the specimen. Also known as a coronal plane.
  • Transverse plane—A horizontal cut that separates the top from the bottom of the specimen. Also known as a cross-sectional plane.
  • Midsagittal plane—A vertical cut down the exact center line of the specimen that separates the left half from the right half.
  • Parasagittal plane—A vertical cut that is off-center that separates the left of the specimen from the right in unequal portions. It does not matter whether it is the left side or the right side that is larger, as long as they are not equal.
Computer generated image of a person's head, showing the transverse cut as a sheet of paper going from the nose out the back of the head, the frontal (coronal) plane as a paper slicing from the tip of the skill down towards the center of the neck and between the ears, the midsagittal plane as a slice from the tip of the head through the neck but cutting along the nose line, and a parasagittal plane as a similar slice (from the tip of the head down to the neck, but through the eye and cheek)

Figure 1-2. The different sectional planes used to expose internal structures.

 

Lab 1 Exercises 1.1

You will be provided with a banana and a plastic knife.

  1. Using a sharpie, draw on your banana a face and simple body: 2 eyes, a nose, mouth, 2 ears, 2 arms, 2 legs.
  2. Using a scalpel carefully cut along the transverse plane about halfway down your banana person.
  3. Look at the banana organs exposed by the transverse cut and imagine what you would see if the banana were a human.
  4. Using the bottom half the body you just cut, use the scalpel to cut along the frontal plane.
  5. Look at the banana organs exposed by the frontal cut and imagine what you would see if the banana were human.
  6. The class will divided into two groups. Using the top half of the banana body created by the transverse cut, one group will use the scalpel to carefully cut along the midsagittal plane; the other group will use the scalpel to carefully cut along a parasagittal plane.
  7. Look at the banana organs exposed by the mid- or parasagittal cut and imagine what you would see if the banana were human.
Banana with marker sketches of where it will be cut along various lines.

Figure 1-3. A banana person prior to being cut along transverse, frontal, and midsagittal or parasagittal planes.