Dermatomes & Myotomes

Dermatomes and myotomes are references to areas of the body that are innervated by spinal nerve segments. Dermatomes will reference the dorsal root, while myotomes is in reference to the ventral root. The dorsal root and the ventral root form a mixed spinal nerve, for example, L5 nerve root.

 

 

 

Dermatome

A dermatome is defined as the spinal segment that provides sensation to the skin in reference to a specific nerve root. The term "derma-" means 'skin' and the term "-tome" means 'to cut'. The spinal nerves cut the skin into different segments into different areas of sensation based upon the respective nerve root.

 

Dermatomes were orginaily identified by a German neurologist in the 1930s by the name of Ofrid Foerster. In 1948, Keegan and Garrett stated "The segmental distribution of the cutaneous nerves in the limbs of man" as they searched for a more definitive mapping of dermatomes compared to Foerster. 

 

 

Myotome

A myotome 

 

 

is defined as the spinal segment that provides sensation to the skin in reference to a specific nerve root. The term "derma-" means 'skin' and the term "-tome" means 'to cut'. The spinal nerves cut the skin into different segments into different areas of sensation based upon the respective nerve root.