Dermatome (anatomy)

A Dermatome is an area of skin that is mainly supplied by a single spinal nerve. 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.

Overview

A dermatome is an area of skin that is mainly supplied by a single spinal nerve. 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.

Function

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.

Clinical significance

In clinical practice, dermatomes are useful to help localize a pathology to a specific spinal nerve. For example, pain or other sensory symptoms may appear within a dermatome when there is a problem with the corresponding spinal nerve or its roots. This can help in the diagnosis of conditions like shingles or herniated discs.

See also

• Cutaneous innervation
• Hilton's law
• Nerve block
• Peripheral nerve

External links

• Dermatome distribution
• Dermatome (neuroanatomy)

• 
  Referred Pain Chart
• Dermatome Map from Grant's Atlas
  Dermatome Map from Grant's Atlas
• 
  Dermatomes of the Upper Limb
• 
  Dermatomes of the Lower Limb
• 
  Dermatomes of the Trunk
• Dermatomes and Cutaneous Nerves - Anterior View
  Dermatomes and Cutaneous Nerves - Anterior View
• Dermatomes and Cutaneous Nerves - Posterior View
  Dermatomes and Cutaneous Nerves - Posterior View