5th Oct

2016

Nerve Roots I HOW THE SKIN IS AFFECTED (DERMATOMES)

Nerves are a little complicated. When an embryo develops the brain and spinal cord are layers of cells separate from layers that become skin, organs, bones and muscles. As the arms and legs grow off the body of the embryo they drag the nerves (and other stuff e.g. blood vessels) out with them. Some of these nerves will conduct impulses from the brain to the limbs (movement) and others will conduct from the limbs to the brain (sensation). Along the way skin tissue with a common origin will have the same nerve supply (e.g. your thumb starts to grow off the point of your shoulder – see picture). Skin supply is a very predictable pattern (dermatomes – see same picture). When a sensory nerve near the spine is irritated (e.g. inflammation, disc herniation or other) that nerves’ area of skin supplied will be the area where tingling,numbness or pain will be felt.
to be continued…..Nerve Roots II HOW THE BONES ARE AFFECTED (SCLEROTOMES)

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