This chapter deals with light and electron microscopical findings of Ruffini corpuscles in hairy and glabrous skin of various mammals and marsupials as well as Ruffini corpuscles in joint capsules of various birds, mammals and marsupials. In glabrous skin (nasal skin, glans penis, prepuce) Ruffini corpuscles are located in the reticular layer of the dermis. In hairy skin, they are located in the reticular layer of the dermis between hair follicles and in the connective tissue capsule of all guard hairs and some vellus hairs as the socalled pilo-Ruffini complex, and also in primate sinus hairs. In joint capsules, Ruffini corpuscles are located within the fibrous layer and within the ligaments of the capsule. Ruffini corpuscles are classified as typical stretch receptors of the Golgi tendon organ type. One can presume that structural change in the connective tissue (injuries, malposition of joints, scars, degenerative processes, aging) also leads to change in the Ruffini corpuscles in the sense that they adjust themselves to the new surroundings.
