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I read the wikipedia entry and I am sort of confused.

In dog, the nose is toward the front. That's anterior. So I conclude that human nose is anterior.

In dog, the head is on the back. So that's dorsal. So I concluded that humans' top head is dorsal.

Yet that's not how things seem to work on anatomy.

We call humans' top head anterior. We also call human nose direction as ventral.

How could that be?

The whole system of anterior, dorsal, ventral, posterior is there so we can see humans like we see dogs (at least anatomically).

Yet it changes again.

So which one is right?

Let me put it this way

Dog's chin is ventral from the eye In humans, is humans' chin ventral from the eye too? or posterior?

What about the nose? Dog's nose is it's anterior most organ.

In humans, is the nose anterior too?

I mean, if we're going to have different terms for humans and dogs, might as well use words like up, down, front, back right?

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It's simple - anterior = ventral and posterior = dorsal for humans. –  biogirl Nov 22 '13 at 16:29
    
I thought anterior posterior axis are always perpendicular to ventral dorsal axis on any area of interests? –  Jim Thio Nov 22 '13 at 23:48
    
These terms are determined for "horizontal" animals. –  biogirl Nov 23 '13 at 9:34
    
In other word, for humans the nose is anterior? That means the chin is dorsal then. We just need to put humans into horizontal position? –  Jim Thio Nov 24 '13 at 11:40
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1 Answer

Humans are are upright in their anatomical position - fig. 1 - from which all directions and terminology stems.

Anatomical Position Figure 1: Anatomical Position

Because of this, anterior is normally the same direction as ventral and posterior normally the same as dorsal - fig. 2.

Normal anterior/ventral and posterior/dorsal

Figure 2: Normal directions in humans

Cranial anatomy is a special case, however, as the entire axis of the body bends round during embryonic development as seen in fig. 3.

Bending of the developmental axis

Figure 3: Bending of the developmental axis

This leads to the cranium being a little odd, where dorsal is equivalent to superior and ventral to anterior in this area of the body only

Resultant differences in brain directions Figure 4: Resultant difference in neuroanatomy conventions

However, for convenience, anterior and posterior retain their original directions even in this area. Therefore you could eliminate a large amount of your difficulties by just using these terms instead for most of the body.


To answer your specific questions:

So I conclude that human nose is anterior

Yes

So I concluded that humans' top head is dorsal. Yet ...We call humans' top head anterior

The top of the head is technically dorsal, however in practice would never really be referred to as such, instead being superior.

In humans, is humans' chin ventral from the eye too? or posterior?

The human chin is both inferior to the eye (looking straight at the face in the coronal plane) and anterior to the eye (but only marginally). It's more obvious if we look at the tip of the nose instead, which again is both inferior and anterior to the eye.

In humans, is the nose anterior too?

Yes, the nose is anterior.

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Is the nose ventral? So top of head is not anterior. –  Jim Thio Nov 24 '13 at 14:14
    
So that means dogs will be different than humans then? –  Jim Thio Nov 24 '13 at 14:22
    
No, the top of the head is superior not anterior and yes, in most animals other than humans the directions will be different as the majority don't walk upright so dorsal wont be the same as posterior and ventral wont be in the same direction as anterior. –  Rory M Nov 24 '13 at 18:01
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