Dermatomes Chart Shingles

Dermatomes Chart ShinglesThe term “dermatome” is a mix of two Ancient Greek words; “derma” implying “skin”, and “tome”, suggesting “cutting” or “thin sector”. It is an area of skin which is innervated by the posterior (dorsal) root of a single spine nerve. As posterior roots are arranged in sections, dermatomes are also. This is why the term “dermatome” describes the segmental innervation of the skin.

Dermatomes Chart Shingles

Dermatomes Definition Chart And Diagram – Dermatomes Definition Chart And Diagram

Surrounding dermatomes often, if not constantly overlap to some degree with each other, as the sensory peripheral branches representing one posterior root usually surpass the limit of their dermatome. As such, the thin lines seen in the dermatome maps are more of a medical guide than a real border. Dermatomes Chart Shingles

This suggests that if a single spinal nerve is impacted, there is most likely still some degree of innervation to that sector of skin coming from above and listed below. For a dermatome to be entirely numb, normally 2 or 3 surrounding posterior roots need to be affected. In addition, it’s important to note that dermatomes are subject to a large degree of interindividual variation. A graphical representation of all the dermatomes on a body surface chart is described as a dermatome map. Dermatomes Chart Shingles

Dermatome maps

Dermatome maps portray the sensory distribution of each dermatome throughout the body. Clinicians can examine cutaneous feeling with a dermatome map as a way to localize lesions within central nervous tissue, injury to particular back nerves, and to figure out the extent of the injury. Several dermatome maps have been established over the years but are typically contrasting.

The most typically utilized dermatome maps in significant textbooks are the Keegan and Garrett map (1948) which leans towards a developmental analysis of this concept, and the Foerster map (1933) which correlates better with medical practice. This post will examine the dermatomes utilizing both maps, identifying and comparing the major differences between them.

Why Are Dermatomes Important?

To understand dermatomes, it is important to understand the anatomy of the spine. The spine is divided into 31 sectors, each with a pair (right and left) of anterior and posterior nerve roots. The types of nerves in the posterior and anterior roots are different.

Anterior nerve roots are accountable for motor signals to the body, and posterior nerve roots get sensory signals like pain or other sensory symptoms. The posterior and anterior nerve roots integrate on each side to form the spinal nerves as they exit the vertebral canal (the bones of the spinal column, or foundation).