The 30 Dermatomes Explained and Located

The 30 Dermatomes Explained and Located

Dermatomes are the body’s defense mechanisms against external threats such as insects, rodents, snakes, etc. They consist of various types of skin cells called melanocytes which produce melanin (the pigment responsible for coloring our skin).

Melanin protects us from harmful ultraviolet rays. There are many different kinds of melanocytes:

Melanoblasts produce the pigment melanin. Melanocytes are found in the epidermis, dermis and basal layer of the skin.

These cells make up a large part of the total number of melanocytes in our bodies.

Molecules produced by other types of cells within our bodies (e.g., keratinocytes) also contribute to coloration and pigmentation.

For example, certain proteins produced by keratinocytes give hair its color.

In addition to melanocytes, there are several other types of immune cells called T lymphocytes that participate in the production of antibodies. Antibodies recognize foreign substances or invaders in our bodies and attack them.

When exposed to sunlight, some melanocyte cells become damaged due to exposure to UV radiation. This causes a loss of pigment and, in some cases, the appearance of noticeable sun spots.

Immune cells also produce other types of antibodies that target specific substances or antigens (foreign materials that trigger an immune response). For example, if you’re allergic to cats, your body produces cytotoxic T cells that attack feline allergens.

In addition to protecting us from invaders and allergens, our immune system also coordinates our body’s healing process. For example, chemical messengers (cytokines) sent out by damaged cells attract immune system cells to the affected area.

In this way, our bodies can repair damaged or injured skin.

The immune system contains several types of white blood cells called natural killer cells. Unlike other types of lymphocytes, natural killer cells do not require an antigen to recognize and destroy infected or malignant cells.

We also have receptors in our bodies that can identify non-self substances, such as viruses or bacteria that have managed to enter our bodies. For example, when viruses enter through our epithelial cells, our immune cells can sense this and sound an alarm.

In response, the immune system can produce antibodies to fight the disease.

Upbringing and immunization also affect the strength of our immune response. When we’re children, we receive immunizations against diseases.

This strengthens our immune system so it can fight these diseases.

Some of us have allergies that cause our immune systems to overreact (e.g., hay fever).

In these cases, our body’s defense mechanisms can attack normal substances such as pollen or pet dander. This causes the symptoms of an allergic reaction. In other words, your immune system shouldn’t attack these substances, but it does.

Toll-like receptors play a role in the immune response. These receptors are capable of identifying disease-causing microbes.

In response, they can activate the appropriate immune cells and proteins to destroy the infectious agent.

The skin also contains several types of immune cells such as macrophages and dendritic cells (DCs). Dendritic cells (DCs) are responsible for raising the alarm (i.e.

activating the immune system) when they encounter dangerous pathogens.

T-cells also play a role in the immune response. These cells can identify diseased or malignant cells in our bodies and attack them (a process called apoptosis).

This is how cancerous cells are destroyed.

The goal of vaccines is to prevent infectious diseases from harming us. Small amounts of dead or weakened pathogens are injected into our bodies so that our immune systems can learn to recognize them.

If we are ever exposed to these pathogens again, our immune systems will be ready to attack.

For example, vaccines can be used to prevent certain strains of the flu. The influenza vaccine is injected into our bodies to teach our immune systems how to react to these viruses.

Immunity can be defined as a condition that protects us from diseases. In other words, if our immune systems are functioning normally, we are unlikely to become ill.

Types of immunity

There are two types of immunity: innate (natural) and acquired (adaptive).

Our innate (natural) immunity is inherited from our parents. This type of immunity develops soon after we are born.

For example, the uterus and breastfeeding can protect a baby from certain diseases.

Acquired (adaptive) immunity is also known as adaptive immunity because it “adapts” to new pathogens that it encounters. This type of immunity develops gradually throughout our lives, as our bodies “learn” to fight specific diseases.

For example, a vaccine can be used to introduce a disease into our bodies. This is known as active immunization.

The vaccine teaches our immune systems how to react when we are later infected with the actual disease.

Inactive immunization, also known as passive immunization, uses antibodies extracted from another person or animal. For example, we can receive an injection of anti-venom serum if we are bitten by a snake.

Sources & references used in this article:

Symptom provocation of fluoroscopically guided cervical nerve root stimulation: are dynatomal maps identical to dermatomal maps? by CW Slipman, CT Plastaras, RA Palmitier, CW Huston… – Spine, 1998 – journals.lww.com

Lumbar plexus posterior approach: a catheter placement description using electrical nerve stimulation by PC Pandin, A Vandesteene… – Anesthesia & …, 2002 – journals.lww.com

Diagnostic lumbosacral segmental nerve blocks with local anesthetics: a prospective double-blind study on the variability and interpretation of segmental effects by AP Wolff, GJ Groen, BJP Crul – Regional Anesthesia & Pain …, 2001 – rapm.bmj.com

Pressure pain sensitivity topographical maps reveal bilateral hyperalgesia of the hands in patients with unilateral carpal tunnel syndrome by C Fernández‐de‐las‐Peñas, P Madeleine… – Arthritis care & …, 2010 – Wiley Online Library

A novel experimental procedure based on pure shear testing of dermatome-cut samples applied to porcine skin by M Hollenstein, AE Ehret, M Itskov, E Mazza – Biomechanics and modeling …, 2011 – Springer

An evidence‐based approach to human dermatomes by MWL Lee, RW McPhee… – Clinical Anatomy: The …, 2008 – Wiley Online Library

Dermatomal somatosensory evoked potentials in the diagnosis of lumbosacral spinal stenosis: comparison with imaging studies by ML Snowden, JK Haselkorn, GH Kraft… – Muscle & Nerve …, 1992 – Wiley Online Library

Role of dermatomes in the determination of therapeutic characteristics of channel acupoints: a similarity-based analysis of data compiled from literature by AS Ferreira, AB Luiz – Chinese medicine, 2013 – Springer