What is Proprioception?
Proprioception (also known as kinesthetic) is the ability to perceive and recognize the position of one's body in space and the state of contraction of one's muscles, even without the support of sight. Proprioception is of fundamental importance in the complex mechanism of motion control.
Proprioceptive receptors (kinesthetic)
It is made possible by the presence of specific receptors, called proprioceptive or kinaesthetic receptors, sensitive to changes in body postures and body segments, which send their signals to some particular encephalic areas. The proprioceptive receptors are constituted by the nerve endings that initiate the neurophysiological process of proprioception. These receptors send impulses which, through the spinal cord, reach the cerebral areas dedicated to the processing of position and movement information, necessary for the correct execution of the movement itself.
These receptors are placed in specific places depending on the function they cover:
Neuromuscular spindle: measures the variation of length of a muscle over time (in practice the speed with which a muscle stretches and shortens during contraction). To do this this will have to cover the whole muscle band in parallel and be equipped with the ability to contract itself.
- Joint capsule sensor: allows you to perceive the displacement, or more specifically, the position of one or more bony segments relative to another. Eg: the bones of the forearm compared to the humerus (with receptor in the joint capsule of the elbow joints).
- Golgi tendon organ: it is placed at the muscle-tendon junction and is sensitive to variations in tension. It is a high-threshold sensor, which preserves the integrity of the tendon in question. When we intend to lift a certain object, the muscles begin to contract even before actual work, because they "wait" for a certain amount of work. However, if the load is exaggeratedly higher than expected, so much so as to damage the tendons involved, by reflex the tendons in question relax by letting go of the load, just to preserve their integrity.
- Vestibular receptors, corresponding to the vestibular ciliated cells, located in the semicorcular canals, the utricle and the saccule (located in the inner ear).
- Corpus of Ruffini, present at the cutaneous and joint capsules and sensitive to prolonged and intense pressure and tactile stimuli
- Pacini corpuscle, present at a deep cutaneous level and sensitive to vibrations