Curious about anatomy?? How much human variation is on the inside of the body. Does it compare to the outside?

Question

Is there as much human variation internally as there is externally? I'm in anatomy class and I'm studying cadavers and my TA will say "This is kind of strange..etc. he/she has an extra vein, or is lacking a bone, or a ligament." How common is this and to what extent to we vary on the inside. I just thought of this because we are all clearly extremely different on the outside..does that carry over into the inners? Does anyone know of an interesting article about human variation that goes into this?

Answer 1

There are significant internal differences from person. There are even differences between the left and right sides of the same person. In my anatomy lab every body was slightly different in almost every aspect. Nerves, arteries and veins all vary in their course. There is however a general scheme just as on our external surfaces but within this scheme there are variations. I would say there is even more variation inside our bodies than there is outside.

Answer 2

Nervers usually follow the course described in the anatomy text. Arteries occasionally vary, and common variations are noted and well known by anatomists and surgeons. For example, there are variations in the origin and distribution of the coronary arteries of the heart. The larger veins are usually as described, but the smaller tributaries vary all over the place.

There are common variations in how the bile duct is formed. A few people are missing a pectoralis major muscle on one side. The list goes on. These are normal variations. There there is a long list of anomalies, less common, sometimes life altering, but usually well described. An example would be the many different presentations of a child with a cleft lip and/or palate.

Answer 3

There are many of variations of internal anatomy. Not as many as external characteristics but still many.

Accessory structures, duplicate structures, structures with different origins or insertions, etc.

This is the reason why I believe that medical students cannot get by studying computer simulations or artificial lab cadavers, and should study all of the 25 or so specimens in the lab. It takes looking for an obturator artery and finding it does not pass through the foramen but instead runs along the femoral vessels to realize you should be careful when you go to tie off an unusual vessel during a hernia operation.

Here is a site with more anatomical variations than anybody would ever want to know about....

http://www.anatomyatlases.org/AnatomicVariants/AnatomyHP.shtml#TOC