Cutaneous innervation refers to the area of the skin which is supplied by a specific cutaneous nerve.
Dermatomes are similar; however, a dermatome only specifies the area served by a spinal nerve. In some cases, the dermatome is less specific (when a spinal nerve is the source for more than one cutaneous nerve), and in other cases it is more specific (when a cutaneous nerve is derived from multiple spinal nerves.)
Modern texts are in agreement about which areas of the skin are served by which nerves, but there are minor variations in some of the details. The borders designated by the diagrams in the 1918 edition of Gray's Anatomy, provided below, are similar but not identical to those generally accepted today. The concept of autonomous territory and the concept of maximal territory of cutaneous distribution for every cutaneous branch are immensely useful to clinicians assessing patients with neurological disorders.
Read more about Cutaneous Innervation: Importance of The Peripheral Nervous System, Importance of The Central Nervous System, The Role of Nerve Endings On The Surface of The Skin, Distribution of Sensory Neurons, Types of Sensory Neurons, Pathways To The CNS