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The stretch reflex (myotatic reflex), or more accurately "muscle stretch reflex", is a muscle contraction in response to stretching a muscle. The function of the reflex is generally thought to be maintaining the muscle at a constant length but the response is often coordinated across multiple muscles and even joints. [ 1 ]
Symptoms associated with central nervous systems disorders are classified into positive and negative categories. Positive symptoms include those that increase muscle activity through hyper-excitability of the stretch reflex (i.e., rigidity and spasticity) where negative symptoms include those of insufficient muscle activity (i.e. weakness) and reduced motor function. [5]
Joints are controlled by two opposing sets of muscles called extensors and flexors, that work in synchrony for smooth movement. When a muscle spindle is stretched, the stretch reflex is activated, and the opposing muscle group must be inhibited to prevent it from working against the contraction of the homonymous muscle. This inhibition is ...
In contrast, the tendon reflex operates as a negative feedback mechanism to control muscle tension. Although the tendon reflex is less sensitive than the stretch reflex, it can override the stretch reflex when tension is great, for example, causing a person to drop a very heavy weight. Like the stretch reflex, the tendon reflex is ipsilateral.
Stretch reflex tests are used to determine the integrity of the spinal cord and peripheral nervous system, and they can be used to determine the presence of a neuromuscular disease. [4] The term "deep tendon reflex", if it refers to the muscle stretch reflex, is a misnomer. "Tendons have little to do with the response, other than being ...
The responses of muscle spindles to changes in length also play an important role in regulating the contraction of muscles, for example, by activating motor neurons via the stretch reflex to resist muscle stretch. The muscle spindle has both sensory and motor components.
Stretch reflex; Triceps reflex — jerking of the forearm when the triceps tendon is hit with a tendon hammer, stimulating the C7 and C6 reflex arcs. Vagovagal reflex — contraction of muscles in the gastrointestinal tract in response to distension of the tract following consumption of food and drink. Vestibulocollic reflex; Vestibulo-spinal ...
Generally, decreased reflexes indicate a peripheral problem, and lively or exaggerated reflexes a central one. [9] A stretch reflex is the contraction of a muscle in response to its lengthwise stretch. Biceps reflex (C5, C6) Brachioradialis reflex (C5, C6, C7) Extensor digitorum reflex (C6, C7) Triceps reflex (C6, C7, C8)