What’s a dermatome?
If a patient comes in to my clinic experiencing a rash in a line across his ribcage, or tingling across his buttock and down the side of the shin, I immediately want to treat his spine. Why? Because of something called dermatomes.
In order to understand dermatomes, we need to understand a little about the anatomy of the spine. The bones of the spine – vertebrae – are stacked on top of one another around the spinal cord. In between each of these vertebrae, a spinal nerve exists the spinal cord, like branches on a tree. Each of these spinal nerves carries sensory, motor, and autonomic information between the spinal cord and the body. Part of each spinal nerve is the dorsal root – this part of the nerve is in charge of sensory information – ie, what we perceive and feel. At the end of the dorsal root is something called the dorsal root ganglion, which contain the cell bodies of nerve cells (neurons) that carry sensory signals from designated parts of the body to the central nervous system.
A dermatome, therefore, is an area of skin that is primarily related to a single spinal nerve. The sensory neurons in a particular dermatome arise from the spinal nerve ganglion at a particular level of the spine.
A common presentation that I see in clinic is shingles along a particular dermatome (frequently across the ribcage). This is because the shingles virus actually lies dormant in one of those dorsal root ganglions, so when it is activated it shows symptoms – pain and the rash – along the dermatome. Another example of dermatome involvement is nerve-type-pain, numbness, tingling, muscle twitching, or changes to skin tone or quality along a dermatome pathway.
Why is this important, from an acupuncture perspective? Because when symptoms follow a particular dermatome, it points to possible nerve root involvement. This means that we can try to activate the dermatome as a whole by stimulating acupuncture points along the spine. These points are called Huatojiaji points.
The Huatuojiaji Points are very common acupuncture points used to treat musculoskeletal or nerve pain in the body. They are not located on an acupuncture meridian, so are referred to as "extra points". There are 34 Huatuojiaji points, which are located on either side of the spine just to the side of the space between the bony spinous process of each vertebrae.
The huatuojiaji points are used to stimulate the function of the spinal nerve that exits the spine at that level and thereby activate an entire dermatome. For example, the middle toe is related to the nerve that exits the spine at lumbar vertebrae 5. Therefore, we can needle the huatuojiaji points level with L5 in order to treat pain, numbness, or tingling in the middle toe. A larger number of Huatuojiaji points can be used together to treat more complex neurological or neuromuscular disorders. Also, because of the significance of so many of the points on the spine, the "huato" points can be used to create balance between multiple organ systems. Most commonly, we stimulate the
Huato points with needles and sometimes electro-acupuncture. We can also stimulate them with cupping and acupressure.
Note that we are NOT needling into any nerves – just as with other acupuncture points, these points energetically help the body to rebalance itself in a particular way. Likewise, from an acupuncture perspective, we can use huatojiaji points to treat symptoms along a dermatome pathway that may not specifically be related to nerve root dysfunction from a biomedical sense. The modern use of these points are a unique integration of a Traditional Chinese Medicine view and a Western biomedical view of the human body.