Dermatome (anatomy)

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Dermatome
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Dermatomes of the Upper and Lower Limbs (Modified, after Keegan, J. J., and Garrett, F. D.)
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Dermatomes of the Upper Parts of the Body, displaying significant overlapping (Modified, from Fender, after Foerster)

A dermatome is an area of skin that is mainly supplied by a single spinal nerve.[1] There are 8 cervical nerves (C1 being an exception with no dermatome), 12 thoracic nerves, 5 lumbar nerves and 5 sacral nerves. Each of these nerves relays sensation (including pain) from a particular region of skin to the brain.

Along the thorax and abdomen the dermatomes are like a stack of discs forming a human, each supplied by a different spinal nerve. Along the arms and the legs, the pattern is different: the dermatomes run longitudinally along the limbs. Although the general pattern is similar in all people, the precise areas of innervation are as unique to an individual as fingerprints.

A similar area innervated by peripheral nerves is called a peripheral nerve field.

Clinical significance[edit]

Referred pain: Conscious perception of visceral sensations map to specific regions of the body, as shown in this chart. Some sensations are felt locally, whereas others are perceived as affecting areas that are quite distant from the involved organ.

A dermatome is an area of skin supplied by sensory neurons that arise from a spinal nerve ganglion. Symptoms that follow a dermatome (e.g. like pain or a rash) may indicate a pathology that involves the related nerve root. Examples include somatic dysfunction of the spine or viral infection. Referred pain usually involves a specific, "referred" location so is not associated with a dermatome.

Viruses that lie dormant in nerve ganglia (e.g. Varicella zoster virus, which causes both chickenpox and herpes zoster) often cause either pain, rash or both in a pattern defined by a dermatome. However, the symptoms may not appear across the entire dermatome.

Important dermatomes and anatomical landmarks[edit]

Following is a list of spinal nerves and points that are characteristically belonging to the dermatome of each nerve:[2]

Dermatomes of the Lower Limb (Modified, from Fender, after Foerster)

Additional images[edit]

See also[edit]

References[edit]

  1. ^ "Dermatomes Anatomy". eMedicine. Retrieved 10/9/2013. 
  2. ^ Key Sensory Points from International Standards for the Classification of Spinal Cord Injury. June 200

External links[edit]