Dermatome skin sensory areas, illustration. The skin on the human body is divided into sensory areas called dermatomes, with each dermatome supplied by a single spinal nerve. These are divided into spinal regions: cervical (C), thoracic (T), lumbar (L), sacral (S) and the trigeminal (V). There are 8 cervical nerves, 12 thoracic nerves, 5 lumbar nerves and 5 sacral nerves. The trigeminal nerve divides into three branches: ophthalmic (V1), maxillary (V2) and mandibular (V2). For a labelled version of this image, please see C056/1996.