Myotomes, Dermatomes & Acupuncture Channels
- Ben Elliot
- Nov 24
- 12 min read
The Bio-Medical terms myotomes and dermatomes provide links, though not always direct parallels, to the Traditional Chinese Medicine (TCM) channel system. In this post, I will investigate these links and explore where they are most usefully used in acupuncture practice.
So what are myotomes, dermatomes and acupuncture channels?
Dermatomes & Myotomes
Dermatomes are a map of the areas of the skin supplied by sensory nerve fibers from each spinal nerve root. They visualise a pathway of the nerve from the point it exits the spine to the areas of the body the nerve supplies. Dermatomes are related to our senses of touch, pain, temperature etc.
Myotomes describe a group of muscles that are all supplied by the same nerve root, ei the nerve may split and branch off at certain points, but all of those branches track back to the same point the original nerve exits from the spinal cord.
When a nerve, or the area of the spinal cord that supplies the nerve gets damaged, we get symptoms along this pathway, not necessarily at the point of the damage. Knowing these pathways helps practitioners target their treatment to the relevant area on or adjacent to the spine.
Causes - Damage to the nerves can occur for a variety of reasons:
Impact injury from a fall, or sudden impact from anything sharp, blunt, or anything in between, can damage the nerve or spine.
Radiculopathy - Compression of the nerve at the root: This can occur for several reasons, bulging discs, tumors or cysts that can develop near or around the nerve and press on it, impairing its function. Infections can create inflammation and swelling, which can compress the nerve. Additionally, spinal stenosis, which is the narrowing of the space where the spinal cord sits, and the exit points of the nerve from the spine, can create pressure and compression on the nerves.
Lack of blood flow: The spinal cord needs a good blood supply to operate. The blood supply can be interrupted by trauma or a blockage of a blood vessel.
Many other conditions can damage the spinal nerves for a variety of reasons, such as diabetes, autoimmune disease, shingles and some congenital conditions.
Symptoms can vary massively as the nerves carry signals for a multitude of purposes. Nerves carry signals in both directions, so if the signal from the mapped area to the brain is interrupted, we would expect to lack sensory information, whereas if the signal from the brain to the area is interrupted, we would expect to see issues with movement and muscle use.
Sensory symptoms - Dermatomes
Pain
Tingling
Numbness
Pins & Needles
Burning Sensation
Motor Symptoms - Myotomes
Muscle weakness or wasting
Difficulty in controlling movements
Our nerves also contain nerve fibres that control our autonomic nervous system, ei. the functions of our body we subconsciously control. We commonly think of these things as heart rate, breathing rate and digestion; however, damage to a nerve can cause a wide range of symptoms such as sweating too little or too much, sexual dysfunction and difficulty going to the loo, depending on which nerve has been damaged.
Dermatome/Myotome Summary
Dermatome map - a map of skin areas.
Myotome map - a map of muscle groups.
Skin and muscle are distributed differently across the body so the maps do not match exactly.
Dermatomes typically form bands or strips, especially on the limbs.
Myotomes don’t form strips. Instead, each spinal root innervates multiple muscles, often scattered around a region. For example:
The L5 dermatome runs down the lateral leg to the dorsum of the foot.
The L5 myotome includes big toe extensors, gluteus medius, tibialis posterior, hamstrings These muscles are not all in a neat strip.
How to use Myotome/Dermatome Maps
Dermatomes are easily mapped onto the body as they relate to sensations we feel on the skin. If you have a sensory symptom in one of the 'segments' pictured in the image below, then you can identify the nerve exit point of the spine as the probable area of damage or impairment. This image from Geeky Medics shows clearly the myotome divisions - each one is labelled with the corresponding nerve exit location.
V1-3 relates to the trigeminal nerve in the head.
C1-7 relates to the nerves that exit above each of the 7 cervical vertebrae
C8 relates to the nerve that exits below the 7th cervical vertebrae. It is is often a point of confusion as we do not have an 8th cervical vertebrae
T1-L5 relate to the nerve roots that exit below the 12 thoracic, and 5 lumbar vertebrae
S1-4 relate to the nerves that exit via the sacral foremen - 4 little holes on either side of our sacrum
S5 relates to the nerve that exits via the sacral hiatus - a small hole at the centre of the sacrum
Myotomes are more difficult to visually map as each nerve that exits the spine will branch off to serve a range of different muscles in different locations. The table below outlines the movements and muscles related to each nerve. If you have movement issues or muscle weakness when performing a movement in column two, it could mean you have damage or impingement to the corresponding nerve to the spinal level in column 1. The precise exit location from the spine are the same as noted in the myotome maps.
Spinal Level | Primary Movement Tested | Key Muscles | Clinical Notes |
C1–C2 | Neck flexion / extension | Longus capitis, rectus capitis | Rarely isolated in exams; tested together. |
C3 | Neck lateral flexion | Scalenes | Often grouped with C4. |
C4 | Shoulder elevation | Upper trapezius, levator scapulae | Shoulder shrug strength. |
C5 | Shoulder abduction | Deltoid, supraspinatus | Classic test for C5 radiculopathy. |
C6 | Elbow flexion & wrist extension | Biceps, brachioradialis, wrist extensors | “Pick up a cup” movement. |
C7 | Elbow extension & wrist flexion | Triceps, wrist flexors | Weak triceps = hallmark of C7 root issues. |
C8 | Finger flexion | Flexor digitorum profundus, lumbricals | Grip strength; finger flexor weakness common in C8 radiculopathy. |
T1 | Finger abduction/adduction | Interossei | Test with finger-squeeze or spreading resistance. |
L1–L2 | Hip flexion | Iliopsoas | Difficulty lifting leg = L2 involvement. |
L3 | Knee extension | Quadriceps | Test with resisted knee extension. |
L4 | Ankle dorsiflexion | Tibialis anterior | “Heel walk” often used; foot drop possible. |
L5 | Big toe extension | Extensor hallucis longus | Best single test for L5 radiculopathy. |
L5 (secondary) | Hip abduction | Gluteus medius/minimus | Pelvic drop on single-leg stance (+ Trendelenburg). |
S1 | Ankle plantarflexion | Gastrocnemius, soleus | “Toe walk”; reduced Achilles reflex. |
S2 | Knee flexion | Hamstrings | Often grouped with S1. |
Acupuncture Channels
The acupuncture channels, or meridians, are used in Traditional Chinese Medicine (TCM) and also map areas of the body. Named 'jing luo' in Chinese, they divide the body into 12 distinct pathways that relate to patterns of disease within the body. There is much discussion on how these pathways were developed in ancient China, culminating in two main theories.
The first is that acupuncture points were discovered over time, based on areas of the body that relieve specific symptoms when stimulated. Points with similar uses were grouped, and the pathways between the points in each group became the channels.
The second theory reverses the order of events and uses the discovery of the Mawangdui text as evidence that the channel pathways were established before any acupuncture points were determined.
Exactly how and why the channels were developed remains a unclear. Either way, neither of these explanations use, or would have been able to use modern Western anatomy in generating this pathway framework, yet there are some parallels.
There are 12 main acupuncture channels, each named after an 'organ' and relating individual functions of the body. Each of the channels either starts or ends on a finger or toe, and from there, they map an area of the leg or arm, and an area of the torso, neck and/or head.
The acupuncture points on a channel can be used to treat issues with its corresponding organ or function, or used to treat the local area or its pathway. When treating a function of the body, ei, circulation, immunity etc, we consider this to be internal pathology. When using an acupuncture point to directly affect the channel pathway, we consider this to be external pathology, such as muscular pain, skin conditions etc.
According to TCM theory, the channels are what contain Qi (more info on what that is or may be - here). The Qi in the channels creates a network of energetics that penetrates all internal and external aspects of the body. When the Qi is disrupted, impaired or blocked, it leads to illness and pain.
The channel system is not limited to the twelve primary channels, as many branches and derivatives exist within the network, and are used in different systems and under different circumstances. For the purposes of comparisons between the acupuncture channels, dermatomes and myotomes, we will stick to the twelve primary channels and the sinew channels. The sinew channels relate more to bones, muscles, tendons, ligaments and joints, but follow the same pathway as the primary and are more superficial and broader.
Links Between Myotomes, Dermatomes & The Acupuncture channels
In a broader sense, the sensory and movement functions related to Myotomes and Dermatomes, are shared with the overall functionality and purpose of Qi. Though, as 'Qi is everything' is a core TCM philosophy, this argument could be viewed as a little tenuous. That said, if you have a read of the previous post What is Qi? - Unravelling The Mystery, it should shed some light on how these similarities have been drawn.
Comparing the pathways of the myotomes and dermatomes to the pathways acupuncture channels provides more tangible parallels, though not in every case. Where some pathways seamlessly crossover between eastern and western ideology, there are as many examples where the different maps simply do not correspond. Here are some of the best examples of then the two worlds do work hand-in-hand.
The Large Intestine channel runs along the C5–C7 dermatome pathway of the arm.
The ulnar nerve, which relates to the C8 dermatome, follows the pathways of the Small Intestine and Heart channels.
GB34 acupuncture point lies in the peroneal nerve territory (L5–S1 myotomes) and is used for weakness and lower limb motor control.
ST36 Acupuncture point corresponds to the L4–L5 myotomes, which provide nerve supply to the muscles we use for knee extension and ankle dorsiflexion.
The Bladder channel runs parallel to the nerve exit points of the spine. Back Shu points, along with Huato Jiaji points are perfect for stimulating both myotomes and dermatomes.
Some actions of the Back Shu points of the Bladder channel relate to the function of the nerve - for example, BL23 - Back Shu for the Kidneys - is positioned below L2, the innervation point that nerve supplies the autonomic functions of the physical Kidneys.
The table below collates all the information that links myotomes, dermatomes and Acupuncture channels.
Dermatome / Myotome / Channel Correlation Chart
Upper Limb
Region | Dermatomes | Myotomes | Main Channels | Key Points & Notes |
Lateral shoulder | C4-C5 | Deltoid (C5) | LI, SI | LI15 sits in C5 dermatome - good for shoulder pain + motor activation. |
Lateral arm | C5-C6 | Biceps (C6) | LI, LU | LI channel tracks C6; LI11 often used for lateral elbow pain. |
Lateral forearm & thumb | C6 | Wrist extension (C6) | LI | LI4: C6-C7 overlaps with trigeminal-cervical nerves for face pain/headache. |
Middle finger | C7 | Triceps (C7) | PC, SJ | SJ channel matches C7; good for tennis elbow, radicular referral. |
Medial forearm | C8 | Finger flexors (C8) | HT, SI | HT/SI points align with C8 sensory distribution. |
Medial upper arm | T1 | Interossei (T1) | SJ | HT3 often used for medial elbow (T1) issues. |
Thorax / Upper Back
Region | Dermatomes | Myotomes | Channels | Notes |
Upper thorax | T1-T4 | Intercostals (T1-T7) | LU, SP, KID | LU channel overlaps T2-T4 - chest, respiratory use. |
Periscapular | C5-T5 | Rhomboids (C4-C5), Serratus Anterior(C5-C7) | SI, BL | SI/BL used heavily for scapular pain because of segment match. |
Abdomen
Region | Dermatomes | Myotomes | Channels | Key Points |
Epigastrium | T5-T7 | Rectus abdominis (T7-T12) | ST, KID | Ren 12 (T7-T9) corresponds to stomach sympathetic supply. |
Umbilical | T10 | Abdominal wall (T10) | ST, SP, Ren | ST25 at T10 - colonic reflex level. |
Lower abdomen | T11-L1 | Lower abdominals | Ren, SP | Ren 4/6 fall at L1 dermatome; relates to reproductive organs. |
Low Back / Pelvis
Region | Dermatomes | Myotomes | Channels | Notes |
Lower thoracolumbar | T12-L2 | Hip flexors (L1-L2) | GB, BL | Useful for psoas-related pain (L1). |
Sacral | L5-S2 | Glutes (L5-S2) | BL, GB | BL channel maps closely to dorsal rami. |
Pelvic floor | S2-S4 | Pelvic floor muscles (S2-S4) | Ren, KID | Explains use of Ren points for urogenital issues. |
Lower Limb
Region | Dermatomes | Myotomes | Channels | Key Points |
Anterior thigh | L2-L4 | Quadriceps (L3-L4) | ST, SP | ST31-34 correlate with femoral nerve distribution. |
Knee | L3 | Quadiceps (L3-L4) | ST | ST35–36 are segmentally aligned for knee pain & motor activation. |
Medial lower leg | L4 | Tibialis anterior (L4) | SP, KID | SP6 influences L4-L5 region via tibial nerve. |
Dorsum of foot | L5 | Toe extensors (L5) | ST, GB | GB41, ST42 align with L5 dermatome - used for sciatica radiating to dorsum. |
Lateral foot | S1 | Plantarflexors (S1) | BL, GB | BL60, 61 & 62 good for S1 radicular symptoms. |
Plantar foot | S2-S3 | Intrinsics (S2-3) | KID | KI1 sits squarely in S2-S3. |
An Integrated Approach in Treatment - Using Acupuncture Modalities
Treatment for myotome and dermatome related issues, on the surface, is quite simple. The location of either sensory or motor issues will guide us to the relevant myotome or dermatome and we can treat it accordingly.
It is the cause of the nerve damage/impingement that will determine exactly which locations and methods we choose to use. Some key considerations are outlined below:
If radiculopathy - compression at the nerve root - is the issue, then the likelihood is that we will want to treat that specific are - either with the Huato point or Bladder point that corresponds to the nerve exit level. However the cause of the compression will influence how we proceed with our treatment.
If the compression is caused by a disc bulge or muscular tension, then huato and bladder points will help to reduce the inflammation in the area, and reduce any tension or shortening of the soft tissues in the area.
While acupuncture can't regenerate a bulging or herniated disc, it can deal with the protective compensatory restriction and tension, and inflammation in the area, allowing a better environment for the disc to recover. This is also the case when conditions such as arthritis/spinal stenosis are the main contributing factor to the nerve compression.
Acupuncture improves blood flow in the area local to needling, simply by tricking the body into sending blood and other pro-healing cells to the site where the needle has penetrated the skin.
Palpating the channel or myo/dermatome pathway, we can also identify any other areas of tension that may be contributing to the nerve impairment at a different area of the body. A good example of this is where we treat the lumbar and sacral spine for sciatic nerve impingement (myotomes and dermatomes at L4, L5, S1, S2, and S3), yet is it common for a further impingement to occur from tension of the piriformis muscle in the buttocks. Channel/Derma/Myo pathway palpation could alert us to this, speeding up recovery.
If the radiculopathy arises from a tumour or cyst, then we would not want to needle them directly. Needling adjacent areas can help with restriction and compensatory effects, however the nature or the cyst or tumour can create additional considerations, so a good understanding or referral/conversation with their GP or consultant is advised.
Using points references in the 'key points' column of the above table give some extra options away from the spine to stimulate specific branches of the nerve. This can be helpful alongside a radiculopathy focus, or some other causes such as impact injuries, or where postural compensation is a factor.
The options discussed would use acupuncture needles in a more western or 'dry needling' approach, even when using TCM acupuncture points. You can read more about the similarities and differences of these approaches in this post. However, when the cause of the nerve issue is related autoimmune and other congenital conditions, a more traditional chinese medicine approach would likely be used. A full consultation would reveal an individualised treatment plan, which would likely include treatment using TCM internal pathology/diagnosis, and perhaps also treatment of the myotomes or dermatomes. The degree of focus on each aspect being determined by the patients individual set of symptoms and circumstance.
There are other methods within the TCM framework that could be used alongside acupuncture, such as cupping and massage. However acupuncture is particularly beneficial for nerve related conditions as the treatment is focussed around the bodies natural reaction to having needles inserted rather than any significant manipulation and movement of the soft tissue which could irritate the nerve further. That said, light stroke massage can be a good tool to sooth nerve irritate when administered along its pathway.
One additional modality that can contribute to quicker results is electro-acupuncture. I've outlined the process and basic theory behind its benefits in a previous post - and the most relevant passage from that post is....
So why is it helpful to run electricity through the body when treating pain? Well, there are a few different ideas about this, and research into the field has thrown up a number of different explanations for the benefits. Electrical impulses sent via nerves from our brains send messages to our muscles to ask them to move - Electro acupuncture can help interrupt or reset these messages, which changes the behaviour of the muscle. Our nerves also carry electrical messages back to our brain to tell it we should be experiencing pain in an area. Electro acupuncture can prevent the transmission of these messages and therefore reduce our experience of pain. There is also good evidence the electro-acupuncture can stimulate the release of feel-good and pain-relieving hormones and chemicals such as endorphins and serotonin.
In summary, the details of myotomes, dermatomes and acupuncture channels create an interesting map of our body and how it functions. Although the theories have been developed centuries apart, the parallels are striking in places. Being able to borrow aspects of one ideology from another means as acupuncturists, we can have the best of all worlds and an array of tools and models to use with our patients.
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