Golgi Tendon Organ

A Golgi tendon organ, or GTO, is a sensory receptor associated with skeletal muscle that detects mechanical force or tension produced through the muscle-tendon system. Golgi tendon organs are located mainly at myotendinous and myoaponeurotic junctions, where muscle fibers connect with tendons or aponeuroses. They form part of the proprioceptive system, which provides the nervous system with information about the mechanical state of muscles and limbs .¹

Within a Golgi tendon organ, sensory nerve endings are intertwined among collagen fibers and are supplied by a group Ib afferent neuron. When muscle contraction places tension on these collagen bundles, the sensory endings are mechanically deformed and the firing rate of the Ib afferent generally increases with force. Golgi tendon organs are particularly sensitive to forces generated by active muscle contraction, although passive stretching can also stimulate them .^1,2

Information from Golgi tendon organs travels to the spinal cord and higher nervous-system centers and contributes to feedback used in the control of muscle force and movement. Their signals interact with spinal interneurons and other sensory and motor pathways, so their effects on muscle activity depend on the motor task and neural context .^1,3

Golgi tendon organs should not be confused with muscle spindles. Muscle spindles lie within muscle and primarily provide information about muscle length and changes in length, whereas Golgi tendon organs are arranged in series with muscle fibers and primarily provide information related to muscle force. The common description of GTOs as simple safety switches that automatically inhibit a muscle whenever tension becomes high is an oversimplification of their physiological role .^2,3