What are dermatomes. How do they relate to spinal nerves. Which health conditions can affect dermatomes. How do doctors use dermatome knowledge for diagnosis.

The Fundamentals of Dermatomes: Skin’s Neural Map

Dermatomes are specific areas of skin that receive sensory information from a single spinal nerve. This intricate system covers the entire body, from the scalp to the toes, creating a neural map that helps the brain interpret touch, pain, and temperature sensations. There are 30 pairs of dermatomes corresponding to 31 pairs of spinal nerves, with the C1 spinal nerve being the sole exception without a dermatome.

The spinal nerves exit the spine in pairs and are classified into five groups based on their point of exit:

• Cervical nerves (C1-C8): Exit from the neck region
• Thoracic nerves (T1-T12): Exit from the torso region
• Lumbar nerves (L1-L5): Exit from the lower back region
• Sacral nerves (S1-S5): Exit from the base of the spine
• Coccygeal nerves: Exit from the tailbone (coccyx)

Each dermatome shares the label of its corresponding spinal nerve, creating a systematic approach to understanding the body’s sensory organization.

Dermatome Distribution: A Detailed Look at Skin-Nerve Connections

Understanding the distribution of dermatomes throughout the body is crucial for medical professionals in diagnosing and treating various conditions. Here’s a comprehensive breakdown of dermatome locations:

Cervical Dermatomes (C2-C8)

• C2: Base of the skull, behind the ear
• C3: Back of the head and upper neck
• C4: Lower neck and upper shoulders
• C5: Upper shoulders and collarbones
• C6: Upper forearms, thumbs, and index fingers
• C7: Upper back, backs of the arms, and middle fingers
• C8: Upper back, inner arms, ring and pinky fingers

Thoracic Dermatomes (T1-T12)

• T1: Upper chest, back, and upper forearm
• T2-T4: Upper chest and back
• T5-T7: Mid-chest and back
• T8-T9: Upper abdomen and mid-back
• T10: Midline of the abdomen and mid-back
• T11-T12: Lower abdomen and mid-back

Lumbar Dermatomes (L1-L5)

• L1: Groin, upper hips, and lower back
• L2: Lower back, hips, and tops of inner thighs
• L3: Lower back, inner thighs, and inner legs just below the knees
• L4: Backs of knees, inner sections of lower legs, and heels
• L5: Tops of feet and fronts of lower legs

Sacral Dermatomes (S1-S5)

• S1: Lower back, buttocks, backs of legs, and outer toes
• S2: Buttocks, genitals, backs of legs, and heels
• S3: Buttocks and genitals
• S4-S5: Buttocks

Coccygeal Dermatome

The coccygeal dermatome is located on the buttocks, specifically in the area directly surrounding the tailbone or coccyx.

Clinical Significance: How Dermatomes Aid in Diagnosis

Dermatomes play a crucial role in medical diagnosis and treatment. When symptoms occur within a specific dermatome, it often indicates damage or disruption to the corresponding nerve. This localization of symptoms helps healthcare providers pinpoint the affected nerve and diagnose underlying conditions more accurately.

For instance, if a patient experiences pain, numbness, or tingling in the area corresponding to the L4 dermatome (backs of knees, inner lower legs, and heels), a doctor might suspect an issue with the L4 spinal nerve. This information guides further diagnostic tests and treatment plans.

Health Conditions Affecting Dermatomes: From Shingles to Nerve Compression

Several health conditions can impact spinal nerves and their corresponding dermatomes. Understanding these conditions is essential for both patients and healthcare providers. Let’s explore some of the most common issues:

Shingles (Herpes Zoster)

Shingles is a viral infection caused by the reactivation of the varicella-zoster virus, which also causes chickenpox. In adults, shingles typically manifests as a rash along one of the thoracic dermatomes on the trunk. The condition often begins with pain, itching, or tingling in the affected area before the rash appears.

Symptoms of shingles may include:

• A painful, blistering rash confined to a specific dermatome
• Headache
• Sensitivity to bright light
• General malaise

In individuals with weakened immune systems, shingles can spread across multiple dermatomes, a condition known as disseminated zoster.

Pinched Nerves

A pinched nerve occurs when a nerve root is compressed by surrounding structures such as bones, discs, tendons, or ligaments. While this compression can happen anywhere along the spine, it’s most common in the lumbar (lower back) region.

Symptoms of a pinched nerve may include:

• Pain radiating along the affected dermatome
• Tingling or numbness in the corresponding skin area
• Muscle weakness in severe cases

The location of these symptoms helps doctors identify the affected nerve, guiding diagnosis and treatment of the underlying cause.

Traumatic Injuries

Traumatic injuries to nerves can result from accidents or surgical procedures. The severity of symptoms can vary widely, depending on the extent of nerve damage. Symptoms may include:

• Loss of sensation in the affected dermatome
• Weakness or paralysis of muscles innervated by the damaged nerve
• Chronic pain or altered sensations in the affected area

Diagnostic Techniques: Leveraging Dermatome Knowledge in Clinical Practice

Healthcare providers use their understanding of dermatomes in various diagnostic techniques to assess nerve function and identify potential issues. Some common methods include:

Sensory Examination

Doctors may test a patient’s ability to feel light touch, pinprick, temperature, and vibration across different dermatomes. Abnormalities in sensation within a specific dermatome can indicate a problem with the corresponding spinal nerve.

Reflex Testing

Certain reflexes are associated with specific spinal levels. For example, the knee-jerk reflex is primarily mediated by the L4 nerve root. Abnormal reflexes can provide clues about nerve root dysfunction.

Electromyography (EMG) and Nerve Conduction Studies

These tests measure electrical activity in muscles and nerves. When correlated with dermatome maps, they can help pinpoint the location and extent of nerve damage.

Treatment Approaches: Addressing Dermatome-Related Conditions

Treatment for conditions affecting dermatomes varies depending on the underlying cause. Here are some general approaches:

Shingles Treatment

• Antiviral medications to reduce the severity and duration of the outbreak
• Pain management techniques, including over-the-counter pain relievers or prescription medications
• Topical treatments to soothe the rash and prevent secondary infections

Pinched Nerve Management

• Conservative treatments such as rest, physical therapy, and anti-inflammatory medications
• Corticosteroid injections to reduce inflammation around the affected nerve
• Surgery in severe cases or when conservative treatments fail

Traumatic Injury Care

• Immediate medical attention to assess the extent of nerve damage
• Surgical intervention if necessary to repair damaged nerves
• Rehabilitation and physical therapy to restore function and manage symptoms

Prevention and Self-Care: Maintaining Dermatome Health

While not all dermatome-related conditions are preventable, there are steps individuals can take to promote overall nerve health and reduce the risk of certain issues:

Shingles Prevention

• Vaccination: The shingles vaccine is recommended for adults over 50 to reduce the risk of developing the condition
• Stress management: Chronic stress can weaken the immune system, potentially increasing the risk of shingles outbreaks
• Maintaining a healthy lifestyle: A balanced diet, regular exercise, and adequate sleep can support overall immune function

Pinched Nerve Prevention

• Practicing good posture to reduce stress on the spine
• Using proper lifting techniques to avoid back injuries
• Maintaining a healthy weight to reduce pressure on spinal nerves
• Regular exercise to strengthen core and back muscles

General Nerve Health

• Staying hydrated to support overall nerve function
• Avoiding smoking and excessive alcohol consumption, which can damage nerves over time
• Managing chronic conditions like diabetes that can affect nerve health
• Wearing protective gear during high-risk activities to prevent traumatic injuries

Future Perspectives: Advancements in Dermatome Research and Applications

As our understanding of dermatomes and neural pathways continues to evolve, new avenues for research and clinical applications are emerging. Some areas of ongoing investigation include:

Precision Medicine in Pain Management

Researchers are exploring how individual variations in dermatome patterns could inform more personalized approaches to pain management and treatment. This could lead to more targeted interventions for conditions like chronic pain syndromes and neuropathies.

Neuromodulation Techniques

Advances in neuromodulation, such as spinal cord stimulation, are being developed with a deeper understanding of dermatome organization. These techniques aim to provide more effective pain relief for patients with chronic nerve-related pain.

Regenerative Medicine

Ongoing research in nerve regeneration and repair could lead to new treatments for traumatic nerve injuries and degenerative conditions affecting dermatomes. Stem cell therapies and bioengineered nerve grafts are among the promising areas of study.

Enhanced Diagnostic Tools

The development of more sophisticated imaging techniques and diagnostic tools may allow for earlier and more accurate detection of nerve-related issues. This could potentially improve outcomes for patients with dermatome-associated conditions.

Understanding dermatomes is crucial for both medical professionals and patients. This knowledge aids in accurate diagnosis, effective treatment, and improved patient care across a wide range of neurological and dermatological conditions. As research continues to advance, our comprehension of these intricate skin-nerve connections will undoubtedly lead to further improvements in medical practice and patient outcomes.

Dermatomes: Definition, chart, and diagram

Dermatomes are areas of skin that send signals to the brain through the spinal nerves. The dermatome system covers the entire body from the hands and fingers to the feet and toes.

The part of a nerve that exits the spinal cord is called the nerve root. Damage to a nerve root can trigger symptoms in the nerve’s corresponding dermatome.

Below, we show the locations of the dermatomes throughout the body. We also describe health conditions that can damage the spinal nerves and affect their dermatomes.

Share on PinterestVarious health problems damage the spinal nerves and affect the surrounding skin.

A dermatome is an area of skin that sends information to the brain via a single spinal nerve.

Spinal nerves exit the spine in pairs. There are 31 pairs in total, and 30 of these have corresponding dermatomes.

The exception is the C1 spinal nerve, which does not have a corresponding dermatome.

The spinal nerves are classified into five groups, according to the region of the spine from which they exit.

The five groups and their points of exit from the spine are:

1. Cervical nerves: These exit the neck region and are labeled C1–C8.
2. Thoracic nerves: These exit the torso region and are labeled T1–T12.
3. Lumbar nerves: These exit the lower back region and are labeled L1–L5.
4. Sacral nerves: These exit the base of the spine and are labeled S1–S5.
5. A coccygeal nerve pair: These exit the tailbone, or coccyx.

Each dermatome shares the label of its corresponding spinal nerve.

Some dermatomes overlap to a certain extent, and the precise layout of the dermatomes can vary slightly from one person to the next.

Below, we list the locations of the dermatomes that correspond to the spinal nerves in each group.

Cervical nerves and their dermatomes

• C2: the base of the skull, behind the ear
• C3: the back of the head and the upper neck
• C4: the lower neck and upper shoulders
• C5: the upper shoulders and the two collarbones
• C6: the upper forearms and the thumbs and index fingers
• C7: the upper back, backs of the arms, and middle fingers
• C8: the upper back, inner arms, and ring and pinky fingers

Thoracic nerves and their dermatomes

• T1: the upper chest and back and upper forearm
• T2, T3, and T4: the upper chest and back
• T5, T6, and T7: the mid-chest and back
• T8 and T9: the upper abdomen and mid-back
• T10: the midline of the abdomen and the mid-back
• T11 and T12: the lower abdomen and mid-back

Lumbar nerves and their dermatomes

• L1: the groin, upper hips, and lower back
• L2: the lower back, hips, and tops of the inner thighs
• L3: the lower back, inner thighs, and inner legs just below the knees
• L4: the backs of the knees, inner sections of the lower legs, and the heels
• L5: the tops of the feet and the fronts of the lower legs

Sacral nerves and their dermatomes

• S1: the lower back, buttocks, backs of the legs, and outer toes
• S2: the buttocks, genitals, backs of the legs, and heels
• S3: the buttocks and genitals
• S4 and S5: the buttocks

The coccygeal nerves and their dermatome

The dermatome corresponding with the coccygeal nerves is located on the buttocks, in the area directly around the tailbone, or coccyx.

Symptoms that occur within a dermatome sometimes indicate damage or disruption to the dermatome’s corresponding nerve. The location of these symptoms can, therefore, help doctors diagnose certain underlying medical conditions.

Some conditions that can affect the nerves and their corresponding dermatomes are:

Shingles

Shingles, or herpes zoster, is a viral infection caused by the reactivation of the varicella-zoster virus. This is the same virus that causes chickenpox.

After the body recovers from chickenpox, the virus can lie dormant and eventually reactivate as shingles.

In adults, shingles typically causes a rash to form on the trunk, along one of the thoracic dermatomes. The rash may be preceded by pain, itching, or tingling in the area.

Some other symptoms of shingles can include:

• a headache
• sensitivity to bright light
• a general feeling of being unwell

A person with a weakened immune system may develop a more widespread shingles rash that covers three or more dermatomes. Doctors refer to this as disseminated zoster.

Pinched nerves

A pinched nerve occurs when a nerve root has become compressed by a bone, disc, tendon, or ligament. This compression can occur anywhere along the spine, but it usually occurs in the lower, or lumbar, region.

A pinched nerve can cause pain, tingling, or numbness in its corresponding dermatome. As such, the location of the symptoms can help a doctor identify the affected nerve.

The doctor then diagnoses and treats the underlying cause of the pinched nerve and recommends ways to relieve the symptoms.

Traumatic injury

A traumatic injury to the nerves may result from an accident or surgery.

The severity of symptoms can help doctors determine the extent of the nerve injury.

Dermatomes are areas of skin, each of which is connected to a single spinal nerve. Together, these areas create a surface map of the body.

Dysfunction or damage to a spinal nerve can trigger symptoms in the corresponding dermatome. Nerves damage or dysfunction may result from infection, compression, or traumatic injury.

Doctors can sometimes use the severity of symptoms in a dermatome to determine the extent and location of nerve damage. They then work to diagnose and treat the underlying cause of the damage.

Dermatomes | HiTech Therapy Online

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High-quality Anatomical Charts that deliver a clear, accurate view of the human body and all its systems. Dynamic full-colour artwork illustrates the cutaneous areas of peripheral nerve innervation and the development of dermatomes.

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Manufacturer: Synergy

SKU: 9936

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This dermatomes poster defines the human dermatomes in beautiful colour illustrations. Dermatomes provide a way to map the approximate areas of skin on the body that is supplied by nerves from a single spinal root. 

Features:

• cutaneous areas of peripheral nerve innervation and corresponding dermatome (main image)
• definition of a dermatome
• the spinal cord with dorsal root ganglion
• the development of dermatomes
• dermatomes in extremities.

All important structures are numbered and/or labelled, making this detailed dermatomes chart is ideal for physiotherapy or other health students learning anatomy. The chart may also be useful for explaining the concept of dermatomes to patients.

This dermatomes poster has been laminated to ensure that it will be long-lasting, and the poster can be written on and wiped off with non-permanent markers.

Size: 51cm (W) x 66cm (L)

Nappi Code: None

This dermatomes poster defines the human dermatomes in beautiful colour illustrations. Dermatomes provide a way to map the approximate areas of skin on the body that is supplied by nerves from a single spinal root. 

Features:

• cutaneous areas of peripheral nerve innervation and corresponding dermatome (main image)
• definition of a dermatome
• the spinal cord with dorsal root ganglion
• the development of dermatomes
• dermatomes in extremities.

All important structures are numbered and/or labelled, making this detailed dermatomes chart is ideal for physiotherapy or other health students learning anatomy. The chart may also be useful for explaining the concept of dermatomes to patients.

This dermatomes poster has been laminated to ensure that it will be long-lasting, and the poster can be written on and wiped off with non-permanent markers.

Size: 51cm (W) x 66cm (L)

Nappi Code: None

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What are dermatomes and where are they

Dermatomes are specific areas of the body innervated by a nerve exiting the spine. The spine is made up of 33 vertebrae and 31 pairs of nerves that are organized throughout the body.

Each nerve that exits the spine is responsible for imparting sensation and strength to a particular area of ​​the body, so whenever a nerve is compressed or cut, that particular area of ​​the body is endangered. In this way, it is possible to determine which part of the spinal cord has been affected by compression, trauma, or a herniated disc, such as when a person says they feel tingling, weakness, or an inability to move their arm or side of the foot.

There are 31 dermatomes in total, which are sort of divided into “slices”, as shown in the following image:

Map of body dermatomes and myotomes

Map of body dermatomes

The best way to identify all dermatomes in the body is to observe a person standing on four supports, because it is easier to perceive “cuts” this way. The following are the main dermatomes of the body:

• Cervical dermatomes – face and neck : they are specially innervated by a nerve emerging from C1 and C2 vertebrae;
• Thoracic dermatomes – Chest : these are areas weakened by nerves that arise from the vertebrae T2 to T12;
• Dermatomes of the upper limbs – Arms and hands : innervated by nerves from the vertebrae C5 to T2;
• Dermatomes of the lumbar and lower extremities – Legs and feet : contain areas innervated by nerves that emerge from the vertebrae L1 to S1;
• Buttocks: is the area innervated by the nerves in the sacrum, from S2 to S5.

The dermatome map is commonly used by physicians and physiotherapists to detect changes or pressures in the spinal cord, because if there is a change in sensation in a certain area of ​​the body, it is easier to determine where the spine is at risk, for example, an injury or a herniated disc.

But in addition, dermatomes can also be used in alternative therapies, such as acupuncture or reflexology, to directly stimulate certain areas of the spinal cord or other organs innervated by the corresponding pair of nerves. Thus, an acupuncturist can insert a needle into the spine to relieve pain and discomfort in other parts of the body.

Map of dermatomes at 4 supports

Difference between dermatome and myotome

Dermatomes refer to sensory changes in the skin and myotomes are responsible for muscle movement in the same area. The table below shows some examples:

900 49 L2

9 0049 Flex forearm and extend wrist

Thus When a person has a sensation of numbness on the side of the foot, it is most likely that a change will occur in the spine, and more specifically between the L5 and S1 vertebrae, because this is their dermatome. But when he has weakness and difficulty in bending his arm, the affected area is the cervical region, specifically C6 and C7, because that area is his myotome.

Split Skin Flap Transplantation – Innovative Vascular Center

Skin grafting using a split skin flap is the easiest way to heal large wound surfaces. To close wounds on the leg, a split skin flap is taken mainly from the surface of the thigh or buttocks.

The meaning of this free skin grafting is to use a thin 0.1-0.8 mm surface layer of the skin, which is taken with a special instrument by a dermatome. This skin flap is perforated, which makes it possible to increase its area by several times and close even large skin defects.

After that, it is placed on the previously prepared perceiving wound and fixed with separate sutures. As a result of the operation, the transplanted skin grows into the wound and closes it. The area where the skin was taken from heals on its own, as the growth part of the skin remains in place.

Benefits of treatment at the Innovative Vascular Center

Compared to other clinics in our country, the Innovative Vascular Center has undeniable advantages in the use of plastic surgery methods for the treatment of vascular patients. In our clinic, the closure of skin wounds and trophic ulcers is performed in a specialized department for the treatment of critical ischemia. Wounds are treated by surgeons who ensure the restoration of blood circulation before plastic surgery, which is necessary for successful wound healing.

We are well aware of the course of wound processes in patients, and we choose the necessary time and method for closing a trophic ulcer or wound for each case. To prepare wounds for skin grafting, we use methods of active preparation of the wound surface. Dressings and antibacterial drugs are prescribed taking into account the sensitivity of the wound microflora.

Thanks to innovative technologies, we manage to heal such wounds that no other clinic in our country takes on!

Preparation for treatment

Before skin plastic surgery, a number of conditions must be met. The human body must be stabilized in terms of blood, protein synthesis. It is necessary to stop the infectious process. Conditions for skin grafting should be local:

• Good bleeding of the wound edges, active juicy granulations.

• The wound is in the granulation stage (without signs of active infection and purulent inflammation).

• The ulcer must be well supplied with blood (circulation must first be restored).

• The defect must be cleaned of dead tissue using physical and chemical methods.

General conditions for skin plastic surgery:

• The level of protein in the blood should be at least 60 g / liter.

• Hemoglobin level is at least 90 g/litre.

• Before transplantation, the patient must be stabilized in general condition.

Direct preparation for the operation involves shaving the site of skin flap sampling, catheterization of the bladder, and installation of an epidural catheter for anesthesia.

Pain relief

During operations on the extremities, epidural or spinal anesthesia is mainly used. Their advantage lies in the local effect on the body. Epidural anesthesia allows prolonged pain relief after surgery.

In order to control the functions of the cardiovascular system, a special monitor is connected to the patient to monitor systemic hemodynamics.

How skin plastic surgery is performed

First, markup and planning is carried out. To close the defect, the skin flap is taken slightly less than the area of ​​the ulcer, because perforations allow it to be stretched. The patient is placed on the operating table so that there is good access to the wound. After processing the surgical field and closing the operation area with sterile sheets, the trophic ulcer is treated surgically. During this treatment, all remaining necrotic tissue areas are removed and pinpoint bleeding from the granulations is provided.

After that, a split skin flap is taken with a dermatome. The technology is pretty simple. A saline solution is injected into the thickness of the skin, which lifts the skin itself and facilitates its separation. After creating such a “water cushion”, the flap is taken using a special tool – an electrodermotomy. This is a special disc knife, which is set to a certain thickness of the required flap for transplantation. After that, the razor of this dermatome removes the thinnest skin flap of the right size.

To increase the area of ​​the skin flap, it is passed through a special tool – a perforator. The perforator in a checkerboard pattern makes small cuts on the flap. Now the flap, when stretched, can cover an area several times larger than its original one.

After perforation, the flap is placed on the wound surface and modeled according to the shape of the defect. In order to fix it, it is mainly sutured with the thinnest sutures to the edges of the wound and pressed with a pressure bandage. Although you can simply place the flap along the contour of the defect and straighten it with tweezers without fixation. The donor site is treated with an antiseptic and closed with a contour bandage with iodopyrone.

Postoperative period

The first dressing after flap transplantation is preferably done 2-3 days after the operation. During this time, most of the flap adheres to the granulation tissue and does not come off when the dressing is changed. The dressing must be changed very carefully, removing it in layers with the help of a tool. Mesh materials (branolind, waxopran) are used to protect the flap from granulation.

During dressing, fixation of the transplanted flap to the granulations is noted, and non-adhering pieces of skin are removed. If there is a local infection, then you need to take a crop and use dressings with antiseptics.

After transplantation, the bandage at the donor site can not be opened if there are no signs of infection. It is enough to change the bandage on top. Over time, the skin epithelializes and the bandage will come off by itself. Usually 14 – 21 days after surgery.

Forecast

If the operation is performed according to indications, provided that the causes of necrosis and trophic ulcers are eliminated, then the results of skin plastic surgery are very good. Correctly performed operation ends with success in 95% of cases. In the postoperative period, the transplanted skin is gradually replaced by its own epidermis, which manifests itself in the appearance of small crusts, under which young skin is visible. The healed defect is treated with a nourishing vitamin cream until complete structural restoration.

Autodermoplasty may be the definitive method of wound closure if the ulcer is not located on the supporting surface or in the area of ​​a large joint. In such places, young skin can be damaged by stress with the formation of trophic ulcers. For supporting and bone surfaces, it is better to use full-layer skin grafting with flaps on a vascular pedicle.

Surveillance program

The operating surgeon must observe the patient until the complete epithelialization of the trophic ulcer on which the skin was transplanted.