The skin has a profuse blood supply, which is important in temperature regulation. A subpapillary plexus in the dermis is derived from the subcutaneous arteries that form a network in the subcutaneous tissue. A subpapillary plexus of venules gives the skin its pink colour: the vessels become dilated when the skin is heated, and thereby make it look red. Most birthmarks consist of dilated capillaries (hemangioma).The skin has a rich sensory innervation. The cutaneous nerves pierce the fascia and branch in the subcutaneous tissue to form plexuses both there and in the dermis. The cutaneous nerves supply both the skin and the subcutaneous tissue. Nerves supplying the skin may form several different types of nerve endings, and these endings have been related in a general way to the basic types of sensations (pain, touch, temperature changes, and pressure, or deep touch).Hairy skin contains simple, free endings and plexuses around the hair follicles. Skin without hair, that of the palms presents the three types of sensory endings that are characteristic of the somatic nervous system; free nerve endings arising from small myelinated fibers, expanded tips, and encapsulated endings. The basic types of sensation, ho