question: Why is the reflex hammer test so frequent in medicine?
comment: They can evaluate the function of some segments of the spinal nerves, and also tell them if ur spinal chord and ur motor neurons are normal. For example, pattelar reflect, the most common test, evaluates the L2, L3 and L4 segments of the spinal chord, and if there's some alteration like minimum or excesive reflect, that could be a neurological problem or something else causing issuesin the spinal chord.
passages: BULLET::::- The Queen Square reflex hammer was designed for use at the "National Hospital for Nervous Diseases" (now the National Hospital for Neurology and Neurosurgery) in Queen Square, London. It was originally made with a bamboo or cane handle of varying length, of average 10 to 16 inches (25 to 40 centimetres), attached to a 2-inch (5 centimetre) metal disk with a plastic bumper. The Queen Square hammer is also now made with plastic molds, and often has a sharp tapered end to allow for testing of plantar reflexes though this is no longer recommended due to tightened infection control. It is the reflex hammer of choice of the UK neurologist.
   Reflex hammer
  
  A reflex hammer is a medical instrument used by practitioners to test deep tendon reflexes. Testing for reflexes is an important part of the neurological physical examination in order to detect abnormalities in the central or peripheral nervous system.
  
  Reflex hammers can also be used for chest percussion.
  
  Section::::Models of reflex hammer.
  
  Prior to the development of specialized reflex hammers, hammers specific for percussion of the chest were used to elicit reflexes. However, this proved to be cumbersome, as the weight of the chest percussion hammer was insufficient to generate an adequate stimulus for a reflex.
   Time to obtain the test result is a key driver for these products. Tests can take as little as a few minutes to develop. Generally there is a trade off between time and sensitivity – so more sensitive tests may take longer to develop. The other key advantage of this format of test compared to other immunoassays is the simplicity of the test – typically requiring little or no sample or reagent preparation.
  
  Section::::Patents.
   Spurling's test is somewhat specific when used for individuals with an abnormal electromyogram study and is a relatively sensitive physical examination maneuver in diagnosing cervical spondylosis or acute cervical radiculopathy. It is not a very sensitive test when used for individuals without classic radicular signs suggestive of cervical radiculopathy. In 2011, one study evaluated 257 patients with clinical cervical radiculopathy and correlated CT scan findings with clinical exam findings using the Spurling's test. The Spurling's test was 95% sensitive and 94% specific for diagnosing nerve root pathology.
   Before the advent of sophisticated medical imaging techniques, surgical exploration was the standard of care. Today, Doppler ultrasound is a common test: it can demonstrate areas of blood flow and can distinguish clearly between epididymitis and torsion. However, as torsion and other sources of testicular pain can often be determined by palpation alone, some studies have suggested that the only real benefit of an ultrasound is to assure the person that they do not have testicular cancer. Nuclear testicular blood flow testing is rarely used.
   Nerve conduction testing is also often done at the same time as an EMG to diagnose neurological diseases.
  
  Some patients can find the procedure somewhat painful, whereas others experience only a small amount of discomfort when the needle is inserted. The muscle or muscles being tested may be slightly sore for a day or two after the procedure.
  
  Section::::Technique.:EMG signal decomposition.
   Researchers testing the effectiveness of drugs on the pain threshold often use the tail flick test to measure the extent to which the drug being tested has reduced the amount of pain felt by the model organism.
   The primary advantage of tail withdrawal assays to other forms of thermal nociception testing, such as the hot-plate test or Hargreaves test, is the relative stability of results with repeated observations. Pain-reflex latency observations from other tests are usually much more variable both across and within subjects than those obtained from the tail withdrawal assay.
  
  Section::::Thermal assays.:Hot plate.
   In 1998, a small-pain-fibers (spf-NCS) method was cleared by the FDA. This method uses an electrical stimulus with a neuroselective frequency to determine the minimum voltage causing conduction. Rather than comparing the data with population averages on a bell-shape curve, which at best has about 65% sensitivity, the patient is his own control. In a three-year LSU Pain Center study, it was found that the nerve requiring the greatest voltage to cause conduction of the A-delta (Fast Pain) fibers identified nerve root pathology with 95% sensitivity. Besides being painless, the test is fast. This test can determine nerve impingement/pathology (pain causing) within the spine (nerve root level) where EMG and Velocity Tests fail. The test uses a potentiometer to objectively measure the amplitude of the action potential at a distant site along the nerve being tested. The patient confirms a sensation when the nerve fires. Objectivity of the patient's response is confirmed by the measurement of nerve recruitment for surrounding nerves and is displayed on the instrument. The impinged nerve (pain fibers) can only report (peak) momentarily while recruiting other nerves to assist and sustain the reporting of the stimulus. Non impinged nerves (pain fibers) do not recruit surrounding nerves and this is readily seen on the display.
   The nerve conduction study consists of the following components
  
  BULLET::::- Motor NCS
  
  BULLET::::- Sensory NCS
  
  BULLET::::- F wave study
  
  BULLET::::- H-reflex study
  
  The nerve conduction study is often combined with needle "electromyography". 
  
  Section::::Technique.:Other.
  
  The Department of Health and Human Services Inspector General recently identified the use of NCSs without a needle electromyography at the same time a sign of questionable billing.
  
  Section::::Technique.:Motor NCS.
   However, caution should be used when assessing patients with acute cervical injuries, critically ill patients, and those with other neoplastic or infectious processes. Cervical instability is also a reason to avoid performing this medical maneuver.
  
  Section::::Accuracy.
   Prior to performing ECT, a set of tests are performed to ensure the patient fits the needs for ECT without further complication in their health status, that may prevent them from being eligible for treatment. Other medical screenings are performed to ensure that their depression is not caused by other medical illness because that can lead ECT to be ineffective. “Before starting electroconvulsive therapy, all patients are screened for medical illnesses, for two reasons. First, a variety of medical illnesses are associated with depression or mania. The second reason for screening the patient is to establish that it is safe to proceed with ECT”. Once the patient passed those two screening, the patient then is evaluated on their medical history, physical exam, psychiatric history, mental status exam, blood count, chemistries, urinalysis, and electrocardiogram. Contraindications and risk include cerebral aneurysms, heart attack, emphysema, multiple sclerosis, and muscular dystrophy.
   The test can be performed by tapping the triceps tendon with the sharp end of a reflex hammer while the forearm is hanging loose at a right angle to the arm. A sudden contraction of the triceps muscle causes extension, and indicates a normal reflex.
  
  Section::::Reflex arc.
  
  The arc involves the stretch receptors in the triceps tendon, from where the information travels through the C7/C8 nerve root to the spinal cord, and the motor signal for contraction returns through the radial nerve.
  
  Section::::Test indicators.
   The strength of a reflex is used to gauge central and peripheral nervous system disorders, with the former resulting in hyperreflexia, or exaggerated reflexes, and the latter resulting in hyporeflexia or diminished reflexes. However, the strength of the stimulus used to extract the reflex also affects the magnitude of the reflex. Attempts have been made to determine the force required to elicit a reflex, but vary depending on the hammer used, and are difficult to quantify.
   Section::::Accuracy.
  
  In studies of diagnostic accuracy, the sensitivity of the Phalen's maneuver ranged from 51% to 91% and its specificity from 33% to 88%.
  
  Section::::Reverse Phalen's test.
   Electrodiagnostic testing (also called electrophysiologic) includes nerve conduction studies which involves stimulating a peripheral motor or sensory nerve and recording the response, and needle electromyography, where a thin needle or pin-like electrode is inserted into the muscle tissue to look for abnormal electrical activity.
   BULLET::::- Golgi tendon reflex
  
  BULLET::::- Hering–Breuer reflex — is a reflex triggered to prevent over-inflation of the lung
  
  BULLET::::- Hoffmann's reflex — also known as the finger flexor reflex; middle finger and thumb response. Test can indicate both neurological damage and nerve regeneration; often combined with the Babinski reflex test.
  
  BULLET::::- Jaw jerk reflex
  
  BULLET::::- Knee jerk or patellar reflex — a kick caused by striking the patellar tendon with a tendon hammer just below the patella, stimulating the L4 and L3 reflex arcs.
   BULLET::::- Tenderness tests: superficial and diffuse tenderness and/or nonanatomic tenderness
  
  BULLET::::- Simulation tests: these are based on movements which produce pain, without actually causing that movement, such as axial loading and pain on simulated rotation
  
  BULLET::::- Distraction tests: positive tests are rechecked when the patient's attention is distracted, such as a straight leg raise test
  
  BULLET::::- Regional disturbances: regional weakness or sensory changes which deviate from accepted neuroanatomy
  
  BULLET::::- Overreaction: subjective signs regarding the patient's demeanor and reaction to testing
   The non-invasiveness and ease of application of RIC have allowed it to be studied in more situations than the original, invasive ischemic preconditioning, which was only realistically applicable in elective surgery. Studies have examined the effects of RIC applied at different times: 
  
  BULLET::::- Pre-conditioning: RIC is applied within the hour prior to an intervention (e.g., elective cardiothoracic and surgical procedures)
  
  BULLET::::- Per-conditioning: RIC is applied at the time of the ischemic event (e.g., evolving heart attack, acute stroke, or trauma)
   In another study done in the late 1900s, 255 patients were examined using a Spurling test and afterwards received an electrodiagnostic examination. The study results showed the Spurling test was 30% sensitive, and 93% specific for finding cervical radiculopathy diagnosed by electrodiagnostic examination. The conclusions drawn from this study demonstrate clinical utility of the Spurling test to confirm cervical radiculopathy rather than for screening purposes. Overall, there continues to be limited data on the specificity and sensitivity of the Spurling test.
   By the mid 1950s most hospitals in Britain routinely used modified ECT, although a few still used unmodified ECT or ECT with muscle relaxants but without anaesthetic. In 1957 a patient who had sustained fractures to both hips whilst undergoing unmodified ECT at a London hospital took legal action. He lost the case but it had far-reaching consequences, encouraging a debate about ECT techniques which led to the abandonment of routine use of unmodified ECT in British hospitals. The case is also famous for having established the Bolam principle.
  
  Section::::Early years: 1938-1969.:Intensive ECT.
   BULLET::::- The Trömner reflex hammer was designed by Ernst Trömner. This model is shaped like a two-headed mallet. The larger mallet is used to elicit tendon stretch reflexes, and the smaller mallet is used to elicit percussion myotonia.
  
  BULLET::::- Other reflex hammer types include the Buck, Berliner and Stookey reflex hammers.
  
  There are numerous models available from various commercial sources.
  
  Section::::Method of use.
   Section::::History.
  
  Mallein was discovered in 1890. Before 1934, glanders was widespread. In the early 1900s, glanders was common in Europe, the United States of America, and Canada, and has been successfully eliminated by mass testing and the slaughter and destruction of campaigns. Glanders is still present in Asia, the Middle East and South America.
  
  Section::::Limitations and benefits.
  
  Section::::Limitations and benefits.:Limitations.
  
  Although Mallein is the most commonly used form of testing for glanders, cross reactions were reported between "Burkholderia mallei" and "Streptococcus equi", which is a bacteria-caused contagious upper respiratory tract infection of equines. This resulted in false-positive reactions.
   BULLET::::- Motor function (Maximum score in upper limb = 66; Maximum score in lower limb = 34)
  
  BULLET::::- Sensory function (Maximum score = 24)
  
  BULLET::::- Balance (Maximum score = 14)
  
  BULLET::::- Range of motion of joints (Maximum score = 44)
  
  BULLET::::- Joint pain (Maximum score = 44)
  
  The maximum total score that can be obtained in Fugl Meyer assessment is 226, though it is common practice to assess all domains separately. The test can be completed in around 40 minutes. To perform the test, the examiner needs a tennis ball, a small spherical shaped container and knee hammer.
  
  Section::::Limitations.
   Section::::Hargreaves.
  
  The Hargreaves assay uses a high-intensity beam of light directed at the hindpaw rather than the tail to induce pain; an investigator then measures the time it takes for the animal to withdraw its hindpaw. In contrast to the tail flick assay, rodents are often unrestrained while the radiant heat source is focused on the hindpaw. Cut-off latency for the Hargreaves assay is commonly set at 10 seconds. The main advantage of this test over the tail flick assay is that it allows independent assessment of treatment effects on both sides of the body.
  
  Section::::Applications.
  