Directions and Planes of Section in Neuroanatomy

Last updated on Wednesday, September 4 2013 by jdmiles

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An orientation to the nervous system, introducing common terms used to describe directions and orientation, specifically as it pertains to neuroanatomy.

When we are discussing directions in anatomy, definitions are based on a person being in the anatomical position, which looks like this:

Planes of Section

Like any three-dimensional object, the human body can be looked at in terms of 3 separate planes. Unlike other three-dimensional objects, anatomists have special names for these planes when dealing with the human body. We call these "planes of section."

The three planes are:

1) the horizontal or transverse plane, which is parallel to the floor when a person is in the anatomical position:

2) the coronal or frontal plane:

3) the sagittal plane:

Bear in mind that "sagittal plane" does not necessarily refer to a cut through the midline of the body. We refer to the most medial or midline sagittal plane as the "midline sagittal plane" or medial sagittal plane:

But any plane parallel to this is also sagittal. For example, in the image below, the blue plane shown is also a sagittal plane:

Directions:

When looking at the brain, as in looking at any other part of the body, anatomical directions are very helpful, particularly in the gross anatomy lab. Phrases like "structure x is below structure y" or "this is above that" can be ambiguous, and depend on how one is holding or viewing the brain. On the other hand, terms like "superior" and "medial" are always made in reference to the anatomical position and the surrounding anatomy, and do not change. The thumbnails below refer to different axes and directions.

Proximal - Distal axis.

Distal:

Distal means away from the main structure. For example, the foot is distal to the knee.

Proximal:

Proximal means closer to the main strucutre. For example, the shoulder is proximal to the hand.

Medial - Lateral Axis:

Medial

Lateral

Anterior - Posterior Axis

Posterior

Superior - Inferior axis

Rostral - Caudal axis

By the end of this section, make certain that you understand what each of these terms mean, and can apply them appropriately. If applicable, make sure you can find each item on a whole brain, brain section, or image of a brain.

horizontal plane

horizontal plane
coronal plane
transverse plane
sagittal plane
parasagittal sections
rostral
caudal
anterior
ventral
posterior
dorsal
superior
inferior
roximal
distal
afferent
efferent

Related images:

Horizontal Plane
An image illustrating a horizontal plane in relation to the human body in anatomical position.

Coronal Plane
An image illustrating a coronal or frontal plane in relation to the human body in anatomical position.

Sagittal Plane
An image illustrating a sagittal plane in relation to the human body in anatomical position.

Planes of Section Fish
An illustration of the planes of section (sagittal, transverse or horizontal, and frontal or coronal), as they apply to a fish.

Planes of Section
An illustration of the planes of section. The illustration shows the sagittal plane, the frontal or coronal plane, and the horizontal or transverse plane.

Anatomical Position
An illustration of the anatomical position.

Proximal
Proximal means towards the midline of the body or towards an origin or point of attachment. Compare to distal.

Distal
Distal means away from the midline of the body or away from an origin or point of attachment. Compare to proximal.

Dorsal
The dorsal or posterior aspect of a person is that part that is towards the surface of the back. Compare to ventral.

Ventral
The ventral or anterior aspect of a person is that part that is towards the surface of the belly. Compare to dorsal.

Rostral-Caudal
Rostral means towards the nose, and Caudal means towards the tail. In humans, this axis takes a sharp turn when it reaches the brain. This makes the rostral-caudal axis different from the anterior-posterior axis and from the inferior-superior axis.

Parasagittal Plane
If a sagittal plane is made through the midline of the body, so that the portions of the body on either side are equal in size, then that is called the midsagittal plane. Any other sagittal section (parallel to but not the same as the midsagittal section) can also be called a parasagittal section.

Rostral Caudal whole body
The red bar indicates the direction of the rostral-caudal axis. In the trunk, caudal and inferior are synonymous, and rostral and superior mean the same thing. Thus the sacrum is caudal to the lumbar vetebrae. In the head however, the axis turns sharply, and caudal is no longer the same as inferior...

Medial
Medial means towards the midline of the body. Your nose is medial to your ears.

Lateral
Lateral means away from the body's midline. If you are like most people, your eyes are lateral to your nose.

Superior
The unnecessarily large green arrow in this image points in the superior direction. Compare this to the rostral-caudal axis.

Inferior
The unnecessarily large red arrow in this image points in the inferior direction. Contrast this to the rostral-caudal axis.

Superior-Inferior whole body
The red bar indicates the direction of the superior-inferior axis. Note that, unlike the rostral-caudal axis, the direction of the superior-inferior axis does not turn in the brain. The arrow points in the superior direction.