ANATOMY OF THE SPINE/DERMATOMES
The spine is a magnificent construction. It is the central structure of the torso and as such plays a pivotal role in everything we do. The spine is also fragile and vulnerable to misuse. Proper spine care goes a long way to making our older years wonderful just as spinal injury can make us miserable. In this situation, the more we understand the details the better position we are in to help ourselves.
The spine is composed of 2 systems. The spinal cord is part of the central nervous system. It connects the brain to the peripheral nervous system, the network of nerves that travel throughout the entire body. The spinal column is part of the skeletal system and is a set of vertebrae and disks which protect the spinal cord which in essence runs down the center of the column. The spinal column consists of 24 vertebrae + the sacrum (5 fused vertebrae) + the coccyx (4 fused vertebrae). Disks are present between every 2 vertebrae to buffer the effects of movement.
As the spinal cord descends, pairs of root nerves break off between each 2 vertebrae one for the right side of the body and one for the left. These root nerves travel to specific parts of the body. When the root nerves encounter problems, we often experience pain. We may feel it locally or in a more distant location, known as referred pain. Sciatica is a case in point where inflammation of the sciatic nerve near the spine causes remote pain in the leg.
One of the reasons we have so much trouble with our spine is that all our lives we use our spine when we should be using our legs. The hip joints and legs are designed for heavy work. The spine is not. Yet we use our spine to do routine tasks like picking something up off the floor. This causes undue stress on the spinal joints. These joints are tender and need to be protected. The long term solution to resolving spine pain is to train yourself to use your legs instead of your back whenever possible. Add to that an increase in core strength to protect the spine and you have a recipe for spine health.
The spine is composed of 2 systems. The spinal cord is part of the central nervous system. It connects the brain to the peripheral nervous system, the network of nerves that travel throughout the entire body. The spinal column is part of the skeletal system and is a set of vertebrae and disks which protect the spinal cord which in essence runs down the center of the column. The spinal column consists of 24 vertebrae + the sacrum (5 fused vertebrae) + the coccyx (4 fused vertebrae). Disks are present between every 2 vertebrae to buffer the effects of movement.
As the spinal cord descends, pairs of root nerves break off between each 2 vertebrae one for the right side of the body and one for the left. These root nerves travel to specific parts of the body. When the root nerves encounter problems, we often experience pain. We may feel it locally or in a more distant location, known as referred pain. Sciatica is a case in point where inflammation of the sciatic nerve near the spine causes remote pain in the leg.
One of the reasons we have so much trouble with our spine is that all our lives we use our spine when we should be using our legs. The hip joints and legs are designed for heavy work. The spine is not. Yet we use our spine to do routine tasks like picking something up off the floor. This causes undue stress on the spinal joints. These joints are tender and need to be protected. The long term solution to resolving spine pain is to train yourself to use your legs instead of your back whenever possible. Add to that an increase in core strength to protect the spine and you have a recipe for spine health.
The spine is divided into 5 sections:
|
Spine Section
Cervical (neck) Thorasic (rib cage) Lumbar (mid back) Sacrum (lower back) Coccyx (tailbone) |
# of Vertebrae
7 12 5 5 fused 4 fused |
# of Root Nerves
8 (C) 12 (Th) 5 (L) 5 (S) |
What is a dermatome?
A dermatome is a root nerve map. The root nerves are numbered along with the letter noted above in parentheses. Each root nerve travels from the spine through the peripheral nervous system to a specific site. For example, the 6th cervical nerve pair C6 controls the motion of the thumbs. C8 controls the little finger. The sacral nerves run down the back of the legs. The lumbar nerves run down the front of the legs.
The right side of this diagram shows the back of the body and the left shows the front.
The right side of this diagram shows the back of the body and the left shows the front.
The illustration to the left is a foot dermatome. Lumbar nerves 4 & 5 and sacral nerve 1 all target the feet. As shown on this diagram, if your left little toe bothers you, it may relate to the first sacral root nerve. In other words, foot problems may be caused by pinching happening in the nerves of the lower back instead something wrong with your foot.
These illustrations are awfully small. If you go to the Internet and do a search on "dermatome images" you will find many others which may be easier for you to use.
These illustrations are awfully small. If you go to the Internet and do a search on "dermatome images" you will find many others which may be easier for you to use.
One fabulous way to use a dermatome is to print it out and take it with you when you see your doctor. You can point to any place on the diagram that bothers you and ask your doctor if spinal inflammation could be involved. A picture in this case is really worth a thousand words.
Using dermatomes.
Here is an example of dermatome use: For several years I had problems with my right foot. I thought I had plantar fasciitis, a painful strain of the heel fascia. Doctors did not help. Nor did daily walks on the beach where wet sand normally has a healing effect on the soles of the feet. Using a dermatome I identified where in my foot I felt the inflammation. Using ice I tested pain response in 3 places on the path of the nerve controlling the injury site. Ice on the foot stopped the pain for 2 minutes. Ice on the inner thigh, 20 minutes. Ice on the lower back, 6 hours! In essence, I felt the pain in a different location from where the inflammation was.
Sciatica in particular can be easily mistreated as we seek pain relief in the wrong location. Instead of the leg, the problem is in the lower back. Not all pain reflects spine inflammation but misdiagnosis is quite possible. Using dermatomes can help you understand the source of your problems and at the least be more aware of the potential conditions.
Sciatica in particular can be easily mistreated as we seek pain relief in the wrong location. Instead of the leg, the problem is in the lower back. Not all pain reflects spine inflammation but misdiagnosis is quite possible. Using dermatomes can help you understand the source of your problems and at the least be more aware of the potential conditions.