Definition
In a normal person, when a muscle tendon is tapped briskly, the muscle immediately contracts due to a two-neuron reflex arc involving the spinal or brainstem segment that innervates the muscle. The afferent neuron whose cell body lies in a dorsal root ganglion innervates the muscle or Golgi tendon organ associated with the muscles; the efferent neuron is an alpha motoneuron in the anterior horn of the cord. The cerebral cortex and a number of brainstem nuclei exert influence over the sensory input of the muscle spindles by means of the gamma motoneurons that are located in the anterior horn; these neurons supply a set of muscle fibers that control the length of the muscle spindle itself.
Hyporeflexia is an absent or diminished response to tapping. It usually indicates a disease that involves one or more of the components of the two-neuron reflex arc itself.
Hyperreflexia refers to hyperactive or repeating (clonic) reflexes. These usually indicate an interruption of corticospinal and other descending pathways that influence the reflex arc due to a suprasegmental lesion, that is, a lesion above the level of the spinal reflex pathways.
By convention the deep tendon reflexes are graded as follows:
0 = no response; always abnormal
1+ = a slight but definitely present response; may or may not be normal
2+ = a brisk response; normal
3+ = a very brisk response; may or may not be normal
4+ = a tap elicits a repeating reflex (clonus); always abnormal
Whether the 1 + and 3 + responses are normal depends on what they were previously, that is, the patient's reflex history; what the other reflexes are; and analysis of associated findings such as muscle tone, muscle strength, or other evidence of disease. Asymmetry of reflexes suggests abnormality.
Technique
All of the commonly used deep tendon reflexes are presented here in a group. In a screening examination you will usually find it more convenient to integrate the reflex examination into the rest of the examination of that part of the body; that is, do the upper extremity reflexes when examining the rest of the upper extremity. When an abnormality of the reflexes is suspected or discovered, however, the reflexes should be examined as a group with careful attention paid to the technique of the examination.
Valid test results are best obtained when the patient is relaxed and not thinking about what you are doing. After a general explanation, mingle the specific instructions with questions or comments designed to get the patient to speak at some length about some other topic. If you cannot get any response with a specific reflex—ankle jerks are usually the most difficult—then try the following:
Several different positions of the limb.
Get the patient to put slight tension on the muscle being tested. One method of achieving this is to have the patient strongly contract a muscle not being tested.
In the upper extremity, have the patient make a fist with one hand while the opposite extremity is being tested.
If the reflex being tested is the knee jerk or ankle jerk, have the patient perform the "Jendrassik maneuver," a reinforcement of the reflex (see Gassel, 1964). The patient's fingers of each hand are hooked together so each arm can forcefully pull against the other. The split second before you are ready to tap the tendon, say "pull."
(Video) Deep Tendon Reflexes (Stanford Medicine 25)In general, any way to distract the patient from what you are doing will enhance the chances of obtaining the reflex. Having the patient count or give the names of children are examples.
The best position is for the patient to be sitting on the side of the bed or examining table. The Babinski reflex hammer (Figure 72.1) is very good. Use a brisk but not painful tap. Use your wrist, not your arm, for the action. In an extremity a useful maneuver is to elicit the reflex from several different positions, rapidly shifting the limb and performing the test. Use varying force and note any variance in response.
Figure 72.1
The Babinski reflex hammer.
Note the following features of the reflex response:
Amount of hammer force necessary to obtain contraction
Velocity of contraction
Strength of contraction
Duration of contraction
Duration of relaxation phase
Response of other muscles that were not tested. When a reflex is hyperactive, that muscle often will respond to the testing of a nearby muscle. A good example is reflex activity of a hyperactive biceps or finger reflex when the brachioradialis tendon is tapped. This is termed "overflowing" of a reflex.
After obtaining the reflex on one side, always go immediately to the opposite side for the same reflex so that you can compare them.
Jaw Jerk
Place the tip of your index finger on a relaxed jaw, one that is about one-third open. Tap briskly on your index finger and note the speed as the mandible is flexed (see Chapter 61 on the trigeminal nerve).
Biceps Reflex
The forearm should be supported, either resting on the patient's thighs or resting on the forearm of the examiner. The arm is midway between flexion and extension. Place your thumb firmly over the biceps tendon, with your fingers curling around the elbow, and tap briskly. The forearm will flex at the elbow.
Triceps Reflex
Support the patient's forearm by cradling it with yours or by placing it on the thigh, with the arm midway between flexion and extension. Identify the triceps tendon at its insertion on the olecranon, and tap just above the insertion. There is extension of the forearm.
Brachioradialis Reflex
The patient's arm should be supported. Identify the brachioradialis tendon at the wrist. It inserts at the base of the styloid process of the radius, usually about 1 cm lateral to the radial artery. If in doubt, ask the patient to hold the arm as if in a sling—flexed at the elbow and halfway between pronation and supination—and then flex the forearm at the elbow against resistance from you. The brachioradialis and its tendon will then stand out.
Place the thumb of the hand supporting the patient's elbow on the biceps tendon while tapping the brachioradialis tendon with the other hand. Observe three potential reflexes as you tap.
Brachioradialis reflex: flexion and supination of the forearm.
Biceps reflex: flexion of the forearm. You will feel the biceps tendon contract if the biceps reflex is stimulated by the tap on the brachioradialis tendon.
Finger jerk: flexion of the fingers.
The usual pattern is for only the brachioradialis reflex to be stimulated. But in the presence of a hyperactive biceps or finger jerk reflex, these reflexes may be stimulated also.
Finger Jerk
Have the patient gently curl his fingers over your index finger, much as a bird curls its claws around the branch of a tree. Then raise your hand, with the patient's hand now being supported by the curled fingers. Tap briskly on your fingers so that the force will transmit to the patient's curled fingers. The response is a flexion of the patient's fingers.
Knee Jerk
Let the knees swing free by the side of the bed, and place one hand on the quadriceps so you can feel its contraction. If the patient is in bed, slightly flex the knee by placing your forearm under both knees by contraction of the quadriceps with extension of the lower leg. If the reflex is hyperactive there is sometimes concomitant adduction of the ipsilateral thigh. Adduction of the opposite thigh and extension of the opposite lower leg also can occur simultaneously if those reflexes are hyperactive. Note that this so-called crossed thigh adduction or leg extension tells you that the reflexes in the opposite leg are hyperactive. They tell you nothing about the state of the reflex in the leg being tested. Use the Jendrassik maneuver if there is no response.
Ankle Jerk
With the patient sitting, place one hand underneath the sole and dorsiflex the foot slightly. Then tap on the Achilles tendon just above its insertion on the calcaneus. If the patient is in bed, flex the knee and invert or evert the foot somewhat, cradling the foot and lower leg in your arm. Then tap on the tendon.
If no response is obtained, have the patient face a chair and kneel on it with the knees resting against the back of the chair, the elbows on the top of the back, and the feet projecting over the seat. First dorsiflex the foot slightly and tap on the tendon. Use the Jendrassik maneuver if this doesn"t work. This position is well suited to observing the relaxation phase of the reflex in patients with suspected thyroid disease.
See DeJong (1967) for a description of numerous other reflexes that are useful in certain situations.
Basic Science
A stretch reflex is the contraction of a muscle in response to stretching of muscle spindles, which are receptors that lie in parallel with extrafusal muscle fibers. The reflex is composed of a two-neuron arc. The afferent neuron, whose cell body is in a sensory ganglion, innervates the spindle. When the muscle spindle is stretched, this neuron fires and monosynaptically excites alpha motoneurons in the anterior horn of the spinal cord. This alpha motoneuron is the second neuron; it supplies the muscle that is being tapped or transiently stretched. The detailed mechanisms underlying the operation of the spindle are quite complex, but considerable knowledge about them is now available in the literature, and new details are added constantly. The muscle spindle is a slender, spindle-shaped structure that is intermingled with the usual muscle fibers. Each spindle is composed of two types of elongated, poorly staining fibers: nuclear bag fibers and nuclear chain fibers. Each contains multiple nuclei. Six to ten of these fibers lie within the spindle's connective tissue sheath. They are called "intrafusal" muscle fibers, since they lie inside the fusiform structure, in contrast to the surrounding "extrafusal" fibers that make up the contractile element of muscle.
Afferent sensory terminals that innervate the spindle fibers are of two types: primary and secondary (Figure 72.2). The spindles fire according to the velocity and amount of stretch placed upon the central nuclear regions of the intrafusal fibers. The degree of stretch communicated to the central portion of the fibers is determined by two factors: the length and change in length of the surrounding extrafusal fibers (see Figure 72.2) and the degree of contraction of the intrafusal fibers (see below).
Figure 72.2
Summary of muscle spindles and tendon organs.
Impulses from the spindle receptors enter the dorsal horn where the information takes four routes: (1) to the cortex; (2) to synapse directly on an alpha motoneuron, which causes immediate contraction of the muscle innervated by the spindle, the agonist; (3) to synapse on an inhibitory neuron which in turn synapses on an alpha motoneuron that goes to a muscle antagonistic to the one innervated by the spindle—thus there is concomitant relaxation of the antagonist as the agonist contracts; and (4) to the cerebellum via the dorsal spinocerebellar tracts.
The previous paragraph describes the course taken by the afferent impulses from the sensory nuclei of the muscle spindles. Recall now that the second component of the spindle was a contractile element, the intrafusal fibers. The firing of the spindle afferents is dependent upon the length of the extrafusal fibers (as outlined above) and the length of the intrafusal fibers. The contraction of the ends of intrafusal fibers and thus the strength of the central portions are controlled by gamma motoneurons: these small neurons are located in the anterior horn and are influenced by the cerebellum, the cortex, and various brainstem nuclei. The probable function of this motor innervation of a sensory structure is to enable these supraspinal structures to "set" and thus ultimately regulate the sensitivity of the spindle. The higher centers and, in particular, the cortex thereby get sensory information from the muscle spindles and, in turn, through the gamma motoneuron, control the amount and quality of information received.
The Golgi tendon organ, which is the second major muscle receptor, is attached between the extrafusal fibers and the tendon. Thus the tendon organ is in series with the extrafusal fibers and will fire as the muscle contracts. The spindles, in contrast, are parallel with (i.e., alongside) the extrafusal fibers and so fire when the extrafusal fibers relax (i.e., are stretched). The impulses from the tendon organ go through the dorsal horn and synapse on an inhibitory interneuron which in turn synapses on an alpha motoneuron that goes to the agonist. Therefore the tendon organ ultimately causes relaxation of the agonist and, by way of interneurons, a facilitation of the antagonist. Information is also conveyed from these receptors to the cerebellum and cortex.
The spinal reflexes that are set up by the mechanisms described above serve the function of keeping the muscle fibers adjusted to a certain length and to a certain tension, thereby maintaining muscle tone and ultimately limb posture.
Clinical Significance
Absent stretch reflexes indicate a lesion in the reflex arc itself. Associated symptoms and signs usually make localization possible:
Absent reflexes and sensory loss in the distribution of the nerve supplying the reflex: the lesion involves the afferent arc of the reflex—either nerve or dorsal horn.
Absent reflex with paralysis, muscle atrophy, and fasciculations: the lesion involves the efferent arc—anterior horn cells or efferent nerve, or both.
Peripheral neuropathy is today the most common cause of absent reflexes. The causes include diseases such as diabetes, alcoholism, amyloidosis, uremia; vitamin deficiencies such as pellagra, beriberi, pernicious anemia; remote cancer; toxins including lead, arsenic, isoniazid, vincristine, diphenylhydantoin. Neuropathies can be predominantly sensory, motor, or mixed and therefore can affect any or all components of the reflex arc (see Adams and Asbury, 1970, for a good discussion). Muscle diseases do not produce a disturbance of the stretch reflex unless the muscle is rendered too weak to contract. This occasionally occurs in diseases such as polymyositis and muscular dystrophy.
Hyperactive stretch reflexes are seen when there is interruption of the cortical supply to the lower motor neuron, an "upper motor neuron lesion." The interruption can be anywhere above the segment of the reflex arc. Analysis of associated findings enables localization of the lesion.
The stretch reflexes can provide excellent clues to the level of lesions along the neuraxis. Table 72.1 lists the segmental innervation of the common stretch reflexes. For example, if the biceps and brachioradialis reflexes are normal, the triceps absent, and all lower reflexes (finger jerk, knee jerk, ankle jerk) hyperactive, the lesion would be located at the C6–C7 level, the level of the triceps reflex. The reflex arcs above (biceps, brachioradialis, jaw jerk) are functioning normally, while the lower reflexes give evidence of absence of upper motor neuron innervation.
Table 72.1
Segmental Innervation of Stretch Reflexes.
The laterality of reflexes is also helpful. For example, if all the reflexes on the left side of the body are hyperactive and those on the right side are normal, then a lesion is interrupting the corticospinal pathways to that side somewhere above the level of the highest reflex that is hyperactive.
Individual nerve and root lesions can be identified by using information about the reflexes along with sensory and motor findings. Aids to the Investigation of Peripheral Nerve Injuries is a valuable pamphlet to carry in your bag to help in testing and analyzing muscles with respect to their innervation.
References
Adams RD. Asbury AK. Diseases of the peripheral nervous system. In: Wintrobe MM, et al., eds. Harrison's principles of internal medicine. 6th ed. New York: McGraw-Hill, 1970; chap 354:1700–1713.
Aids to the investigation of peripheral nerve injuries. 2nd ed. Medical Research Council, War Memorandum 7. London: Her Majesty's Stationery Office, 1943.
Brodal A. Neurological anatomy. 3rd ed. New York: Oxford University Press, 1981.
Bussel B, Motin C, Pierrot-Deseilligny E. Mechanism of monosynaptic reflex reinforcement during Jendrassik maneuver in man. J Neurol Neurosurg Psychiatry. 1978;41:40–44. [PMC free article: PMC492960] [PubMed: 621529]
DeJong RN. The neurologic examination. 3rd ed. New York: Harper & Row. 1967;589–607.
DeMyer W. Technique of the neurological examination: a programmed text. 2nd ed. New York: McGraw-Hill, 1974;189–210.
Delwaide PJ, Toulouse P. The Jendrassik maneuver: quantitative analysis of reflex reinforcement by remote voluntary muscle contraction. Adv Neurol. 1983;39:661–69. [PubMed: 6660115]
Gassel MM, Diamantopoulos E. The Jendrassik maneuver. Neurology. 1964;14:555–60. , 640–42. [PubMed: 14161754]
Garnit R. The functional role of the muscle spindles: facts and hypotheses. Brain. 1975;98:531–56. [PubMed: 130185]
Henneman E. Peripheral mechanisms involved in the control of muscle. In: Mountcastle V, ed. Medical physiology. 13th ed. St. Louis: CV Mosby, 1974;617–35.
Impallomeni M, Flynn, Kenny RA, Kraenzlin M, Pallis CA. The elderly and their ankle jerks. Lancet. 1984;1:670–672. [PubMed: 6142359]
Magee KR. Clinical analysis of reflexes. In: Vinken PJ, Bruyn GW, eds. Handbook of clinical neurology. Amsterdam: North-Holland Publishing. 1969;1:237–56.
(Video) Deep Tendon Reflexes of the Upper ExtremitiesMatthews PBC., ed. Mammalian muscle receptors and their central actions. London: Edward Arnold, 1972.
Paulson GW. Some lesser-known reflexes in neurology. Ohio State Med J. 1973;69:515–16. [PubMed: 4723328]
FAQs
What is a good deep tendon reflex score? ›
By convention the deep tendon reflexes are graded as follows: 0 = no response; always abnormal. 1+ = a slight but definitely present response; may or may not be normal. 2+ = a brisk response; normal.
What is a normal DTR response? ›There are five primary deep tendon reflexes: bicep, brachioradialis, triceps, patellar, and ankle. Each reflex corresponds to a particular root and muscle and will evaluate the integrity of the root and associated nerve. NINDS grading of DTR ranges from 0 to 4. A normal response is grade 2 or 3.
What does it mean if you have no deep tendon reflexes? ›Unilateral absence of a deep tendon reflex implies disease at the peripheral nerve or root level. Diffuse reduction or absence of deep tendon reflexes suggests a more generalized process affecting the peripheral nerve, seen frequently in peripheral neuropathies secondary to diabetes, alcohol abuse, or inflammation.
What is a normal reflex score? ›Reflexes are graded on a scale of 0 to 4. A grade of 2 indicates normal reflexes. A grade of 3 indicates hyperreflexia; 4 indicates hyperreflexia with clonus. Decreased relexes are indicated by 1 (hyporeflexia) or 0 (no reflex elicited, even using the Jurassic maneuver.
What is an abnormal reflex? ›Definition. Any anomaly of a reflex, i.e., of an automatic response mediated by the nervous system (a reflex does not need the intervention of conscious thought to occur). [ from HPO]
What does a reflex test tell you? ›If you think you have brisk reflexes you can ask your doctor for a reflex test. This test helps determine how effective your nervous system is by assessing the reaction between your motor pathways and sensory responses. During the test, your doctor may tap your knees, biceps, fingers, and ankles.
What reflex is abnormal in adults? ›The Snout Reflex
If an adult has the same reflex response when their upper lip is tapped, it's considered abnormal and may indicate that the frontal lobes of the brain are damaged.
Usually, absent reflexes are caused by an issue with the nerves in the tendon and muscle. You may have other muscle symptoms along with areflexia, like weakness, twitching, or atrophy.
How do you assess DTR? ›Deep Tendon Reflexes (Stanford Medicine 25) - YouTube
What will happen if we don't have reflex action? ›Responses: They will break down.
Why I dont have knee jerk reaction? ›
Clinical Significance
An absent or diminished patellar tendon reflex may be due to PNS pathology affecting either the afferent sensory neurons or the efferent motor neurons. If the reflex is absent or diminished combined with sensory loss, the lesion is likely in the afferent sensory nerves.
Hypokalemia, hypocalcemia, and hypomagnesemia resulting from electrolyte loss have manifested as flaccid weakness involving the lower limbs and trunk muscles with diminished deep tendon reflexes. These electrolyte disturbances are also responsible for the ECG findings.
What are the 5 deep tendon reflexes? ›There are five primary deep tendon reflexes: biceps, brachioradialis, triceps, patellar, and ankle.
How can I improve my reflexes? ›- Pick a sport, any sport – and practise. What exactly do you want to improve your reflexes for? ...
- Chill out. ...
- Eat a lot of spinach and eggs. ...
- Play more video games (no, really) ...
- Use your loose change. ...
- Playing ball. ...
- Make sure you get enough sleep.
Reflex testing contributes to accurate bedside diagnosis in many cases of neuromuscular disease, providing localising diagnostic information that cannot be obtained by any other method (including clinical neurophysiological and neuroradiological investigations).
Why do doctors tap your knee? ›It is also known as a deep tendon reflex (DTR) because the doctor is actually tapping on a tendon called the patellar (say: puh-TEL-ur) tendon. This tap stretches the tendon and the muscle in the thigh that connects to it. A message then gets sent to the spinal cord that the muscle has been stretched.
What are the 4 types of reflexes? ›There are different types of reflexes, including a stretch reflex, Golgi tendon reflex, crossed extensor reflex, and a withdrawal reflex.
Why do doctors check your knee reflexes? ›Medical author Dr Janice Rachel Mae explains that doctors routinely use reflex tests to check if there are any problems in the nervous system involved in movement, nerve functioning or health of the connective tissue in the knee or leg.
Why do neurologists check reflexes? ›Reflexes. Your neurologist tests your automatic response to specific triggers. These tests show how well nerves between your brain and body communicate.
Do you have normal reflexes with MS? ›Often reflexes in MS are overactive or brisk, rather than lost. Scratching the sole of the foot might cause the big toe to go upwards, called a Babinski sign. Decreased feeling to light touch, vibration and pin prick sensation can occur in one or all limbs.
Which reflex can be tested to determine whether damage? ›
Autonomic Neuro-Muscular Reflex Testing (ANMRT) is a new exam used to identify the root cause of an injury through a systematic, neurological approach. Like the knee-jerk reflex, ANMRT is a collection of involuntary reflexes that confirms the health of the peripheral nervous system.
What part of the nervous system controls reflexes? ›In addition to regulating the voluntary movements of the body, the somatic nervous system is also responsible for a specific type of involuntary muscle responses known as reflexes, controlled by a neural pathway known as the reflex arc.
Why do doctors flick your fingernails? ›During this brief examination, your doctor evaluates the possibility of spinal cord compression caused by a lesion or another underlying nerve condition such as cervical myelopathy. The test is based on how your hand's reflexes respond to a quick flick of a fingernail.
Why do doctors scrape the bottom of your foot? ›The Babinski reflex — also called the plantar reflex — is a response to stimulation of the bottom of the foot. It can help doctors evaluate a neurological problem in people over age 2. If your child has this reflex and doesn't show any other signs of neurological problems, however, there's probably no need to worry.
What is it called when your reflexes don't work? ›People with areflexia don't have typical reflexes, such as a knee-jerk reaction. Areflexia is usually caused by an underlying condition related to disease or injury to the nervous system.
What are the top 3 common nervous system disorders? ›Among the most common are epilepsy, Alzheimer's, and stroke.
Neurological disorders are central and peripheral nervous system diseases, that is, they occur in the brain, spine, and multiple nerves that connect both.
Numbness or tingling. Weakness or a reduced ability to move any part of the body (not caused by pain). Tremors, tics, or other unusual movements, such as a walking (gait) change or mouth smacking. Coordination problems, such as dropping things, tripping, or falling more often.
How do nurses check for deep tendon reflexes? ›Brachioradialis Deep Tendon Reflex Examination | Nursing Head to Toe ...
How does the nurse assess deep tendon reflexes? ›To perform deep reflex tendon testing, place the patient in a seated position. Use a reflex hammer in a quick striking motion by the wrist on various tendons to produce an involuntary response.
What does a strong knee reflex mean? ›Spasticity is stiff or rigid muscles. It may also be called unusual tightness or increased muscle tone. Reflexes (for example, a knee-jerk reflex) are stronger or exaggerated. The condition can interfere with walking, movement, speech, and many other activities of daily living.
What problem would you face if there was no system of reflex actions in your nervous system? ›
They don't need us to think about them i.e they happen involuntarily. We don't have time to think about these decisions. Thus, the absence of these actions would be very dangerous for us and could cause us great harm, like burning of our hands when we touch a hot object.
What are the two main advantages of a reflex action and why are they important? ›A reflex action is a quick,immediate,spontaneous and automatic response to any external or internal stimulus generally without the involvement of the brain and the spinal cord. The advantages are: It helps to protect the body from stimulus. It is quick and hence effective.
Why is reflex action not controlled by the brain? ›In a reflex action, the brain plays no part. The spinal cord, which reacts without thinking about how to respond to stimuli, is in charge of these automatic actions. It elicits no meaningful response in the brain.
Does the knee-jerk reflex involve the brain? ›The knee-jerk reflex is the simple monosynaptic reflex. Note: Hence, there is no brain involvement; the jerk reflex of the knee is having no input from the brain.
What does absent ankle jerk mean? ›The absence of an ankle jerk in a patient with back and or sciatica pain may indicate nerve root compression. We must beware as this reflex may be normally absent in a number of patients.
Does low sodium cause decreased deep tendon reflexes? ›Severe or acute hyponatremia may be associated with headache, nausea, vomiting, lethargy, malaise, and decreased deep tendon reflexes and may cause brain edema and brain compression due to fluid overload. An abrupt decrease in sodium levels may also induce coma, convulsion, or respiratory arrest [7].
How do you feel if your electrolytes are low? ›...
Signs of electrolyte imbalance
- Dizziness.
- Cramps.
- Irregular heartbeat.
- Mental confusion.
A level under three can cause muscle weakness, spasms, cramps, paralysis and respiratory problems. If it continues, kidney problems may occur.
What does a strong knee reflex mean? ›Spasticity is stiff or rigid muscles. It may also be called unusual tightness or increased muscle tone. Reflexes (for example, a knee-jerk reflex) are stronger or exaggerated. The condition can interfere with walking, movement, speech, and many other activities of daily living.
What reflex is abnormal in adults? ›The Snout Reflex
If an adult has the same reflex response when their upper lip is tapped, it's considered abnormal and may indicate that the frontal lobes of the brain are damaged.
How do you assess DTR? ›
Deep Tendon Reflexes (Stanford Medicine 25) - YouTube
Why are deep tendon reflexes normal in myasthenia gravis? ›Deep tendon reflexes are preserved. Patients with MG may experience unrelated infections or illnesses that precipitate a myasthenic crisis, which causes acute worsening of their symptoms. A myasthenic crisis is defined as an exacerbation exhibiting muscular weakness sufficient to endanger the patient's life.
What does it mean if I have no reflexes in my knees? ›The normal response is a 'knee jerk'. This is an example of a reflex, which is an involuntary muscular response elicited by the rubber hammer tapping the associated tendon. When reflex responses are absent this could be a clue that the spinal cord, nerve root, peripheral nerve, or muscle has been damaged.
Why do some people have stronger reflexes? ›Some people are born with faster reflexes. Electrical impulses actually travel more quickly through their nerves. But you can also speed up nerve conduction through practice. A soccer player, for example, can improve his running or kicking.
What does it mean if you don't have a knee-jerk reflex? ›If your doctor taps on a tendon and there isn't a reflexive movement in the muscle, it's a sign of a health issue. Usually, absent reflexes are caused by an issue with the nerves in the tendon and muscle. You may have other muscle symptoms along with areflexia, like weakness, twitching, or atrophy.
Why do doctors tap your knee? ›It is also known as a deep tendon reflex (DTR) because the doctor is actually tapping on a tendon called the patellar (say: puh-TEL-ur) tendon. This tap stretches the tendon and the muscle in the thigh that connects to it. A message then gets sent to the spinal cord that the muscle has been stretched.
Why do doctors check your knee reflexes? ›Medical author Dr Janice Rachel Mae explains that doctors routinely use reflex tests to check if there are any problems in the nervous system involved in movement, nerve functioning or health of the connective tissue in the knee or leg.
What are the 5 deep tendon reflexes? ›There are five primary deep tendon reflexes: biceps, brachioradialis, triceps, patellar, and ankle.
How do nurses check for deep tendon reflexes? ›Brachioradialis Deep Tendon Reflex Examination | Nursing Head to Toe ...
How does the nurse assess deep tendon reflexes? ›To perform deep reflex tendon testing, place the patient in a seated position. Use a reflex hammer in a quick striking motion by the wrist on various tendons to produce an involuntary response.
Why is reflex testing important? ›
Reflex testing contributes to accurate bedside diagnosis in many cases of neuromuscular disease, providing localising diagnostic information that cannot be obtained by any other method (including clinical neurophysiological and neuroradiological investigations).
Can you have mild myasthenia gravis? ›Myasthenia gravis can range from mild to severe. In some cases, symptoms are so minimal that no treatment is necessary. Even in moderately severe cases, with treatment, most people can continue to work and live independently. Life expectancy is normal except in rare cases.
What were your first myasthenia gravis symptoms? ›In more than half of people who develop myasthenia gravis, their first signs and symptoms involve eye problems, such as: Drooping of one or both eyelids (ptosis) Double vision (diplopia), which may be horizontal or vertical, and improves or resolves when one eye is closed.
What are the stages of myasthenia gravis? ›Myasthenia gravis (MG), a neuromuscular disease characterized by weakness and fatigue, is typically divided into five types: generalized, congenital, ocular, juvenile, and transient neonatal myasthenia gravis, depending on time of disease onset, the cause of the neuromuscular dysfunction, and the muscle groups affected ...