Free nerve ending

Overview
A free nerve ending (FNE) is an unspecialized, afferent nerve ending, meaning it brings information from the body's periphery to the brain. Free nerve endings are unencapsulated and have no complex sensory structures, unlike those found in Meissner's or Pacinian corpuscles. They are the most common type of nerve ending, and are most frequently found in the skin. They penetrate the epidermis and end in the stratum granulosum. These nerve endings are responsible for detecting temperature, mechanical stimuli (such as pressure), pain (nociception), and information about touch. Some FNEs can also detect stretch stimuli.

The majority of Aδ (A delta) fibers (group III) and C (group IV) fibers end as free nerve endings.

Different types of FNE can be fast-adapting, intermediate, or slow-adapting. Aδ fibres are fast-adapting, while C fibers are slow-adapting.