This MedLibrary.org supplementary page on Dermatomes is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:
Related Sponsors
A Dermatome is an area of skin associated with a pair of dorsal roots from the spine. The significance of dermatomic regions is important as pain in a dermatomic area may indicate spinal damage or neurological stenosis. A compressed spinal nerve may show as pain elsewhere on the body, according to the dermatomic area covered by the compressed nerve. A similar area innervated by peripheral nerves is called a peripheral nerve field.
The body can be divided into regions that are mainly supplied by a single spinal nerves. There are eight cervical (one for the head, and one for each cervical vertebra), twelve thoracic, five lumbar and five sacral spinal nerves.
This innervates the body in a patterned form. Along the thorax and abdomen it is simply 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.
Contents |
Clinical significance
Dermatomes are useful in neurology for finding the site of damage to the spine. Viruses that infect spinal nerves such as Herpes zoster infections (shingles), can reveal their origin by showing up as a painful dermatomic area. Herpes zoster, a virus that is dormant in the dorsal root ganglion, migrates along the spinal nerve to affect only the area of skin served by that nerve. Symptoms are usually unilateral but in the immune suppressed, they are more likely to become bilateral and symmetrical, meaning that the virus is present in both ganglia of a dorsal root ganglion pair.
Important dermatomes and anatomical landmarks
- C2 - posterior half of the skull cap
- C3 - area correlating to a high turtle neck shirt
- C4 - area correlating to a low-collar shirt
- C6 - (median nerve) 1st digit (thumb)
- C7 - (radial nerve) 2nd and 3rd digit
- C8 - (ulnar nerve) 4th and 5th digit, also the funny bone
- T4 - nipples.
- T5 - Inframammary fold.
- T6/T7 - xiphoid process.
- T10 - umbilicus (important for early appendicitis pain)
- T12 - pubic bone area.
- L1 - inguinal ligament
- L4 - includes the knee caps
Additional images
 Distribution of cutaneous nerves. Ventral aspect. |
 Distribution of cutaneous nerves. Dorsal aspect. |
 Cutaneous nerves of right upper extremity. |
 Diagram of segmental distribution of the cutaneous nerves of the right upper extremity. |
See also
External links
 |
This neuroscience article is a stub. You can help Wikipedia by expanding it. |
Wikipedia content modification information:
- This page was last modified on 22 August 2008, at 23:43.
Wikipedia Authorship and Review
Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.
Wikipedia Usage Guidelines
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Dermatomes".
The URL for this specific entry is:
All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.