Diaphragm explanation/Phrenic nerves

[Guest guest]

I didn't copy all of this article as it is from an article about T.B. but had

the best explanation of the diaphragm I've heard as yet. And this explains my

upper arm and shoulder atrophy its phrenic nerve related! ~>Becky M.

http://www.lung.ca/tbhistory/treatment/nervecrush.html

Situated at the bottom of the chest and separating the chest from the abdomen

are two muscles, one on each side and together known as the diaphragm. The

muscle on the right side receives its nerve supply from the right phrenic nerve

and that on the left, naturally, from the left phrenic nerve.

As you breath in, both muscles contact and are pulled downward thus increasing

the volume of the chest and drawing air into the lungs. At the end of a deep

breath the muscles relax and rise pushing the air out of the lung. In other

words breathing in is an active or contracting phase of the diaphragm and

breathing out is a passive or relaxing phase of the diaphragm.

Both phrenic nerves, that is, right and left, rise from a group of nerves in the

neck, some of which go on to supply the shoulder muscles and arm muscles and the

phrenic nerve enters the chest behind the collar bone. However, between the

place where it originates and where it disappears into the chest it is readily

accessible through a small incision made in the skin just above the collarbone.

You can compare the crushing of this nerve to the cutting of a wire carrying

electrical current to a lamp. By cutting the wire the light is extinguished and

similarly by crushing the phrenic nerve the current which causes the contraction

of the diaphragm is temporarily cut off.