GOLGI TENDON ORGAN: ANATOMICAL STRUCTURE, FUNCTIONS - ANATOMY AND PHYSIOLOGY - 2025

The Golgi tendon organ, also known as the neurotendinous spindle, is a specialized neurological formation, with high content of collagen, that has sensory reception functions. It is one of the specialized organs that connect the muscle with the central nervous system.

This organ has a portion that is inserted into the muscle fiber and another that does so directly into the tendons. It is responsible for informing the cerebral cortex of the level of tension of the muscles to avoid an exaggerated load that causes a muscle injury.

From Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body (See "Book" section below) Bartleby.com: Gray's Anatomy, Plate 938, Public Domain, https://commons.wikimedia.org/w/index. php? curid = 566884

Through the neurological impulse generated by the Golgi organ, the cerebral cortex can send a warning signal that relaxes a muscle in danger of injury. This mechanism is known as the reverse myotatic reflex.

The reverse myotatic reflex serves as a defense mechanism to prevent muscle damage such as tearing and loss of tendon attachment.

Anatomy

The Golgi organ is made up of a thin body made up of elastic collagen fibers that are capable of reacting to the contractions and stretches of the muscle fibers.

The collagen fibers that make up the body of the Golgi organ are encapsulated. These capsules are made up of fibrous tissue and each one of them is connected to a set of muscle fibers, between 3 and 12, on the one hand, and to the tendon itself on the other.

The connecting neurological cells pierce the capsule and branch within it. These cells are responsible for carrying the nerve impulse from the muscle to the spinal cord and finally from there to the cerebral cortex.

Likewise, the cerebral cortex sends neurological signals back to the muscle that will indicate if it is capable of exerting more tension or if it must relax to avoid damage.

Sudden muscle relaxation in the face of muscle overload is a defense response that triggers the brain to prevent injury.

Features

The Golgi tendon organ is part of the proprioceptive system. This means that it is one of the specialized organs that sends information to the brain about its own movements and makes them conscious.

The proprioceptive system is made up of neurological receptors that are located in the joints, muscles, and ligaments.

Proprioception tells us the position of the body, that is, muscle stretching and contraction, degree of joint angulation, position of the upper and lower limbs, speed of movement, among others.

The Golgi organ is specifically responsible for sending information about the degree of stretch and muscle tension.

By Neuromechanics - Own work, Public Domain, This function is achieved through signals perceived by a neurological center that carries information to the spinal cord. In a fraction of seconds, this signal reaches the cerebral cortex and is processed.

If the muscle tension is too strained and the brain interprets it to be dangerous and can cause injury to that muscle, such as a tear or loss of bone attachment, a signal is sent back to stop movement and relax the muscle.

All this process is carried out automatically. The individual does not make any of these neurological signals consciously, only feels the pain and cancels the movement.

- Myotatic reflex and reverse myotatic reflex

There is a group of muscle reflexes that are activated automatically in response to a movement that generates a high load on the muscle and represents a danger.

The myotatic reflex and the reverse myotatic reflex are two of the reflexes of the muscular system. These reflexes are activated by the nervous system as a defense mechanism to prevent muscle damage.

Myotatic reflex

The myotatic reflex is activated when there is an exaggerated stretching of muscles and tendons. When the muscle fibers are elongated by stretching, a signal is received that travels through the spinal cord to the brain. If this signal is processed as damaging to the muscle, muscle contraction is activated to prevent damage.

A well-known example of a myotatic reflex is the patellar reflex, which is easily found by the physician when stimulating the knee tendon with the physical examination hammer.

From ChristinaT3 at English Wikipedia, CC BY-SA 3.0,

Inverse myotatic reflex

Contrary to this, the reverse myotatic reflex is activated in the event of an intense and sudden muscle contraction.

To understand it, it is important to know that the Golgi organ is in constant communication with the central nervous system. Every time there is any degree of tension in the muscle fibers, this organ sends the corresponding signal.

The brain is in charge of processing the information sent and returns a motor response so that the necessary adjustments are made to be able to execute the desired movement.

However, when there is a sudden muscle contraction and the muscle contracts and a sudden great tension is generated, an intense signal passes through the receptors of the Golgi organ to the spinal cord and the cerebral cortex.

Once the signal is released, the degree of tension on the muscle is interpreted. If the signal of contraction or overload is translated as a degree of tension that can cause muscle pull injury or tear, an inhibition response is activated that results in muscle relaxation.

In this way, the contraction is inactivated and the muscle relaxes as a defense mechanism against the overload exerted.

- Clinical importance of the Golgi organ

When the Golgi organs are activated by the intense and abrupt musculotendinous tension, the phenomenon of the reverse myotatic reflex occurs, which results in the relaxation of the muscle.

However, as in many other movements, this response becomes less intense as the muscle is accustomed to the level of tension that is needed.

Thus, as a muscle can be stretched little by little without causing the contraction caused by the myotatic reflex, a muscle can maintain a sustained contraction and reach higher levels of tension through regular training of that muscle group without being activated relaxation caused by the reverse myotatic reflex.

From Redactoresamg - Own work, CC BY-SA 4.0, High performance athletes must turn to this resource in order to increase their loads. Especially runners and weightlifters, are benefited when it comes to training properly knowing the muscle physiology.

References

1. Lyle, MA; Nichols, TR. (2019). Evaluating intermuscular Golgi tendon organ feedback with twitch contractions. The journal of physiology. Taken from: ncbi.nlm.nih.gov
2. Delwaide, P. J; Cordonnier, M; Charlier, M. (1976). Functional relationships between myotatic reflex arcs of the lower limb in man: investigation by excitability curves. Journal of neurology, neurosurgery, and psychiatry, 39 (6), 545–554
3. Katz, R. (2001). Reevaluation of physiological mechanisms generating the stretch reflex: new hypotheses on the physiopathology of spasticity. Taken from: ncbi.nlm.nih.gov
4. Bhattacharyya KB (2017). The stretch reflex and the contributions of C David Marsden. Annals of Indian Academy of Neurology. Taken from: ncbi.nlm.nih.gov
5. Mukherjee, A; Chakravarty, A. (2010). Spasticity mechanisms - for the clinician. Frontiers in neurology. Taken from: ncbi.nlm.nih.gov