Proprioception

Proprioception (PRO-pree-o-SEP-shun (IPA pronunciation: ); from Latin proprius, meaning "one's own" and perception) is the sense of the relative position of neighbouring parts of the body. Unlike the six exteroceptive senses (sight, taste, smell, touch, hearing, and balance) by which we perceive the outside world, and interoceptive senses, by which we perceive the pain and the stretching of internal organs, proprioception is a third distinct sensory modality that provides feedback solely on the status of the body internally. It is the sense that indicates whether the body is moving with required effort, as well as where the various parts of the body are located in relation to each other. The Position-Movement sensation was originally described in 1557 by Julius Caesar Scaliger as a 'sense of locomotion'. Much later in 1826 Charles Bell expounded the idea of a 'muscle sense' and this is credited with being one of the first physiologic feedback mechanisms. Bell's idea was that commands were being carried from the brain to the muscles, and that reports on the muscle's condition would be sent in the reverse direction. Later, in 1880, Henry Charlton Bastian suggested 'kinaesthesia' instead of 'muscle sense' on the basis that some of the afferent information (back to the brain) was coming from other structures including tendon, joints, skin, and muscle. In 1889, Alfred Goldscheider suggested a classification of kinaesthesia into 3 types: muscle, tendon, and articular sensitivity. In 1906, Sherrington published a landmark work which introduced the terms 'proprioception' 'interoception', and 'exteroception'. The 'exteroceptors' being the organs responsible for information from outside the body such as the eyes, ears, mouth, and skin. The interoceptors then gave information about the internal organs, while 'proprioception' was awareness of movement derived from muscular, tendon, and articular sources. Such a system of classification has kept physiologists and anatomists searching for specialised nerve endings which transmit data on joint capsule and muscle tension (such as muscle spindles and Pacini corpuscles).