WHAT IS THE REVERSE MYOTATIC REFLEX? - ANATOMY AND PHYSIOLOGY - 2025

The reverse myotatic reflex is an automatic physiological response that causes a muscle that is under great tension to relax. It is called inverse because it is the antagonistic response of the myotatic reflex.

Contrary to the reverse myotatic reflex, the myotatic reflex causes the automatic contraction of a muscle in response to a forced stretch. Both are monosynaptic reflexes, this means that a single muscle group responds to the stimulus without involving complex movements.

By Amiya Sarkar - Own work, CC BY-SA 4.0, The inverse myotatic reflex is activated as a defense mechanism of the body against some stimulus that the brain interprets as a danger to the integrity of the muscle. The signals that are sent from the muscle to the brain to activate the reverse myotatic reflex, travel from a specialized neurological formation located in the tendons. This structure is called the Golgi tendon organ.

Physiology

Reflex is the automatic response of a part of the body to a specific stimulus. This answer usually refers to a movement, but can be of another type. For example, when the salivary glands expel saliva at an acid smell.

So reflexes are automatic internal responses to external stimuli and can help establish the state of consciousness of an individual who is in a coma.

Reflexes occur by complex neural connections that cause stimuli to travel from the stimulated area to the cerebral cortex. Once there, the brain processes the information and sends a response back to the stimulated area.

- Osteotendinous reflexes

There are several types of reflections. Among them are osteotendinous reflexes, also called deep or myotatic reflexes.

These types of reflexes are widely known since many of them are evaluated as part of the physical examination performed by a doctor for general medical consultation.

From ChristinaT3 at English Wikipedia, CC BY-SA 3.0, The myotatic reflex is a stretch reflex. This means that the stimulus that triggers it is the sudden and excessive stretching of a tendon, the response being the contraction of the muscle.

On the contrary, in the reverse myotatic reflex the stimulus is the contraction and overload of the tendon resulting in the relaxation of the muscle.

These stimuli are received by a special structure that is located in the tendons and is called the Golgi tendon organ.

- Golgi tendon organ

Also known as the neuro-tendon spindle, the Golgi tendon organ is a specialized neurological formation that contains motor neurons. It is located in the tendons of all muscles and reacts through reflex responses to some stimuli.

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

The Golgi tendon organ is the neurological structure that is responsible for transmitting stimuli through the spinal cord to the cerebral cortex.

Finally, it is the cerebral cortex that processes this information and sends the corresponding signals.

The reverse myotatic reflex is a defense mechanism of the body that prevents injury to the muscle that is subjected to great overload. Thus, when the muscle is in forced contraction, that signal is sent through the spinal cord and receives the response to relax.

This response is a special mechanism that prevents an overloaded muscle from being injured.

Monosynaptic response

When we refer to monosynaptic response reflexes, we are talking about those reflexes in which a response of a single muscle group occurs to a specific stimulus from that tendon.

The reverse myotatic reflex, as part of the tendon reflexes, is an example of a monosynaptic response.

The physician obtains the monosynaptic response easily by examining the patient with the hammer, specially designed to evaluate reflexes.

By Internet Archive Book Images - https://www.flickr.com/photos/internetarchivebookimages/14598069420/Source book page: https://archive.org/stream/medicaldiagnosi00gree/medicaldiagnosi00gree#page/n1238/mode/1up, No restrictions, When a stimulus of forced contraction reaches the specialized neurons located in the Golgi organ of a tendon, they send the signal to the spinal cord receiving a message of relaxation from the specific muscle group.

The polysynaptic response is a more complex response that is not limited to just one muscle group, but involves many.

Clinical considerations

The myotatic reflex and the reverse myotatic reflex are important in the clinical evaluation. Through the response obtained by the physical examination of the reflexes, the doctor can make the diagnostic approach of several diseases.

The reflex can be exacerbated, weak, slow, or very fast. Based on these responses, it can begin to establish whether the patient has a neurological disease that has affected the neuronal response to stimuli.

Pathological reflexes associated with myotatics may also occur, such as the razor reflex.

The razor reflex is a pathological response to extreme stretching of a muscle. When performing the extension movement, the muscle is stimulated by increasing its tone. This stimulus is captured by the Golgi organ of the tendon, which sends the signal and finally causes the muscle to contract.

It's called a razor reflex because the movement occurs abruptly, just like the stimulus that triggered it.

Interest for athletes

The reverse myotatic reflex is especially important in athletes, specifically runners and weightlifters. These types of athletes, especially when they are high performance athletes, seek to take their muscle loads to the extreme in order to improve their marks.

For runners, special warm-ups are recommended before engaging in a long, forced exercise that is likely to keep the muscles contracting for a long time.

By Hans Peters / Anefo - http://proxy.handle.net/10648/abcd7be4-d0b4-102d-bcf8-003048976d84, CC0, Both the stretches that stimulate the myotatic reflex, and the runs that can stimulate the reverse myotatic reflex, are activities that you should do frequently, since the continuous stimulation helps to increase the stress capacity that the muscle can support.

Weightlifters are also looking to increase the amount of weight they can lift to reach their maximum goals. The only way to achieve this without injuring the muscles is to increase the weights progressively.

In these activities, great attention should be paid to exercise and not to perform forceful movements in a sudden way, since they can trigger difficult-to-treat responses that can become disabling.

References

1. Walkowski, AD; Munakomi S. (2019). Monosynaptic Reflex. StatPearls Treasure Island. Taken from: 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