Definition: Proprioceptors are specialized sensory receptors on nerve endings found in muscles, tendons, joints, and the inner ear. These receptors relay information about motion or position and make us aware of our own body position and movement in space. Proprioceptors detect subtle changes in movement, position, tension, and force, within the body.
The proprioceptors of the musculoskeletal system are found in the tendons and in the muscle fibers. These proprioceptors include:
- Muscle spindles (stretch receptors). These are the primary proprioceptors in the muscle that are sensitive to changes in muscle length.
- The golgi tendon organ. This proprioceptor in the tendon near the end of the muscle fiber is sensitive to changes in muscle tension.
- The pacinian corpuscle. This proprioceptor is responsible for detecting changes in movement and pressure within the body.
How Proprioceptors Protect Us From Injury
In addition to providing information about the movement and positioning of our body, head, arms and legs, the proprioceptors can trigger certain protective reflexes. The "stretch reflex," for example, is activated when the proprioceptors sense too much stretch or force on a muscle or tendon. To resist an unsafe change in muscle length that may lead to a torn muscle or tendon, the reflex causes the stretched muscle to contract, shorten and protect the muscle or tendon from injury.
