Medical The preganglionic fibers which supply the thoracic viscera

[Asmaa Mohammad]

Hello,

In my textbook, I read that the preganglionic fibers which supply the thoracic viscera originate in the lateral horn of the upper 4 thoracic segments.

I read too that the the preganglionic fibers which supply the head and neck originate in the lateral horn of the first and second thoracic segments.

What I don't understand is how would the preganglionic fibers of the first and second thoracic segments (i.e. T1 and T2) supply both the region of the thoracic and the region of head & neck?

 

[BillTre]

Hi Asmaa,

Your question seems not too clear to me:
Your book says:
T4 --> thoacic viscera
and
T1/2 --> head and neck
It doesn't say T1/2 does both (from your description).

Although I am not an expert on the autonomic nervous system, there seems to be an obvious explanation (if in fact T1/2 go to more than one of these anatomical regions).

There will be many neurons projecting out to the autonomic ganglia. The different neurons could be projecting their axons to different places.
The autonomic ganglia are in a connected chain adjacent to the spinal cord.
Axons going out from the spinal cord to the sympathetic ganglia can turn and go anterior to other more anterior ganglia that in turn innervate the head and neck.
The neurons from T1/2 could do this, or some of the neurons at these levels could do it while other neurons in T1/2 could just go straight out (go neither anterior nor posterior).
Neurons do this kind of thing frequently.

 

[Asmaa Mohammad]

T4 --> thoacic viscera

The book said that the upper 4 segments supply the thoracic viscera, i.e. T1, T2, T3 and T4 (that's how I interpreted it).

There will be many neurons projecting out to the autonomic ganglia. The different neurons could be projecting their axons to different places.

Neurons do this kind of thing frequently.

I think I got it. Nice explanation!

But let's wait until one expert in ANS will tell us more information.