Guided Tour of the Visible Human: Planes of Section
Relative to a 3D coordinate system, the body may be sectioned in one of three planes.
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| Transverse (X-Y) | Coronal (X-Z) | Sagittal (Y-Z) |
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Transverse (or axial) sections form a series of circumferential
slices - rather like slicing the body into a series of
pancakces and stacking them atop one another. Transverse sections run
top to bottom (superior to inferior).
Your chin is inferior to your forehead but superior
to your knees. The terms cranial (as in the cranium of your head)
and caudal (latin for 'tail') may be used interchangeably with
superior and inferior.
You can go through the entire body in this animation of
transverse sections (1.63MB GIF).
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Coronal sections follow front to back, as though cutting through
a corona, or halo, around the head. In medical terms anterior
means front, and posterior means back. A similar group of terms
includes ventral (front), and dorsal (back).
The following animation runs anteriorly from the nose to the posterior
of the head. (137K GIF or
300K Quicktime movie).
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Sagittal sections follow from one side of the body to
the other - left to right, or right to left. In medical terms
lateral means 'outside', and medial 'inside' in the sense of
lying in the middle. Your nose is medial (and inferior!)
to your eyes, while your ears lie lateral to both your eyes
and nose. The following animation traverses through the body from
the right shoulder to the left, and back again.
(600K GIF or 300K
Quicktime Movie).
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To simplify the visualization of 3D structures from 2D images, try this short animation of the sagittal sections. Specific organs have been marked in the images. Focus on a single organ, and follow how it appears in different sections. If you assume images are 2-3 centimeters apart, would you be able to create an approximate 3D shape of the organ using the information from the 2D images?
How the sections were made..
The original setions were cut in the transverse plane. The body was frozen in a special material to preserve the tissues and organs. Sections were literally 'shaved' off the frozen block in micro-thin layers to expose underlying tissues. A picture would be taken and another thin layer removed to expose more of the body. The process of cutting through one plane obviously ruins the possibility of obtaining sections in the other two planes (coronal and sagittal in this case). The digital information from the transverse images was thus placed in a computer to create a three dimensional matrix of the body from which coronal and sagittal sections could be generated.Many computer animations have been created using the data from the Visible Human Project. A few of the more interesting adventures include a short trip through the colon, and some java applets for viewing the Visible Woman.