question: how come sometimes when you use the restroom and you put your foot up into tippy-toes your legs start shaking sporadically oh, and you can't seem to control it?
comment: It is a reflex response, but not a clonus reflex. Clonus is a sign of neurological damage, namely upper motor neurone lesions. Putting your foot on its tiptoes won't give you an upper motor neurone lesion thankfully! It's part of the Golgi tendon reflex. Golgi tendons are small receptors located in every muscle that protect them from over stretching damage. They do this by recognising when a muscle is over stretched and then sending a message to your spinal cord- which then sends a message back telling the muscle to contract to prevent it hurting itself. When OP goes up onto his tiptoes the Golgi tendons sense his calf (gastrocnemius, soleus and to a lesser degree plantar is) is stretching, so the it sends the message to the spinal cord and we get the contraction reflex. So then his leg rises due to plantar flexion at the ankle and the calf muscles relax. After they relax, his leg drops again- we get the stretch- then the stretch reflex and the cycle repeats, carrying on the continual bounce of his leg.
passages: Section::::Disorders.:Restless leg syndrome.
   Dancers who over-rotate while utilizing their turnout can experience an overuse based syndrome known as Plantar Fasciitis. It is geared towards dancers and runners because of the constant heel rise to toe in their activities and exercises; it is caused by the excessive force used on that specific part of the foot, the plantar fascia. For dancers, it is most likely developed from a repetitive grandplié or relevé. If a dancer has this condition, it is unnecessary to stop dancing unless the case is severe. Modifications in the movement and overall correcting the issue is enough. It can resolve within several months and it can be repelled with the proper practice.
   Additionally, the effect of the sensory input varies depending on the phase of the pattern in which it occurs. For example, during walking, resistance to the top of the swinging foot (e.g., by a horizontal stick) causes the foot to be lifted higher to move over the stick. However, the same input to the standing foot cannot cause the foot to lift or the person would collapse. Thus, depending on the phase, the same sensory input can cause the foot to be lifted higher or held more firmly to the ground. "This change in motor response as a function of motor pattern phase is called reflex reversal, and has been observed in invertebrates (DiCaprio and Clarac, 1981) and vertebrates (Forssberg et al., 1977). How this process occurs is poorly understood, but again two possibilities exist. One is that sensory input is appropriately routed to different CPG neurons as a function of motor pattern phase. The other is that the input reaches the same neurons at all phases, but that, as a consequence of the way in which the network transforms the input, network response varies appropriately as a function of motor pattern phase."
   Foot drop is characterized by steppage gait. While walking, people suffering the condition drag their toes along the ground or bend their knees to lift their foot higher than usual to avoid the dragging. This serves to raise the foot high enough to prevent the toe from dragging and prevents the slapping. To accommodate the toe drop, the patient may use a characteristic tiptoe walk on the opposite leg, raising the thigh excessively, as if walking upstairs, while letting the toe drop. Other gaits such as a wide outward leg swing (to avoid lifting the thigh excessively or to turn corners in the opposite direction of the affected limb) may also indicate foot drop.
   With correct placement of the needle electrode and level of electrical impulse, there is often an involuntary toe flex or fan, or an extension of the entire foot. However, for some patients, the correct placement and stimulation may only result in a mild sensation in the ankle area or across the sole of the foot.
  
  The treatment protocol requires once-a-week treatments for 12 weeks, 30 minutes per session. Many patients begin to see improvements by the 6th treatment. Patients who respond to treatment may require occasional treatments (~ once every 3 weeks) to sustain improvements.
   Proper treatment of autonomic dysreflexia involves administration of anti-hypertensives along with immediate determination and removal of the triggering stimuli. Often, sitting the patient up and dangling legs over the bedside can reduce blood pressures below dangerous levels and provide partial symptom relief. Tight clothing and stockings should be removed. Straight catheterization of the bladder or relief of a blocked urinary catheter tube may resolve the problem. The rectum should be cleared of stool impaction, using anaesthetic lubricating jelly. If the noxious precipitating trigger cannot be identified, drug treatment is needed to decrease elevating intracranial pressure until further studies can identify the cause.
   PLMD is characterized by increased periodic limb movements during sleep (PLMS), which must coexist with a sleep disturbance or other functional impairment, in an explicit cause-effect relationship. Usually, these involuntary movements come from lower extremities (including toes, ankles, knees, and hips), although they can also be observed in upper extremities, occasionally. PLMS seem to be common features within a large number of people, and identifying whether or not these movements are clinically relevant for a distinct diagnosis of PLMD remains a challenge for clinical and scientific fields. Moreover, diagnosis of PLMD cannot be used when narcolepsy, restless legs syndrome (RLS), REM sleep behaviour disorder (RBD) or untreated obstructive sleep apnea (OSA) is already diagnosed, since abnormal movements during sleep are frequent in these disorders.
   The causes of foot drop, as for all causes of neurological lesions, should be approached using a localization-focused approach before etiologies are considered. Most of the time, foot drop is the result of neurological disorder; only rarely is the muscle diseased or nonfunctional. The source for the neurological impairment can be central (spinal cord or brain) or peripheral (nerves located connecting from the spinal cord to an end-site muscle or sensory receptor).
   After the tap of a hammer, the leg is normally extended once and comes to rest. The absence or decrease of this reflex is problematic, and known as Westphal's sign. This reflex may be diminished or absent in lower motor neuron lesions and during sleep. On the other hand, multiple oscillation of the leg (pendular reflex) following the tap may be a sign of cerebellar diseases. Exaggerated (brisk) deep tendon reflexes such as this can be found in upper motor neuron lesions, hyperthyroidism, anxiety or nervousness. The test itself assesses the nervous tissue between and including the L2 and L4 segments of the spinal cord.
   A short, mild-mannered man, Mr. Twiddle, plays the congas in a nightclub jazz combo; the incessant noise (the horn players point their instruments directly at Twiddle's head) cause him to have nervous tremors, and he leaves in the middle of the act while the rest of the band continues to play. Later, his psychiatrist Dr. I.M Jittery tells him he is a "very sick man" suffering from "trombonosis" and recommends a relaxing trip to a quiet, secluded locale to restore his nerves. The doctor warns Twiddle of the consequences of not doing so ("Your nervous system will shatter, you will simply..."blow up!""), and has his wife (a nurse) make travel arrangements.
   Another important step in diagnosing BFS is checking the patient for clinical weakness. Clinical weakness is often determined through a series of strength tests, such as observing the patient's ability to walk on his or her heels and toes. Resistance strength tests may include raising each leg, pushing forward and backward with the foot and/or toes, squeezing with fingers, spreading fingers apart, and pushing with or extending arms and/or hands. In each such test the test provider will apply resisting force and monitor for significant differences in strength abilities of opposing limbs or digits. If such differences are noted or the patient is unable to apply any resisting force, clinical weakness may be noted.
   Physical tests are an easy way to determine the severity of the intention tremor and impairment of physical activity. Common tests that are used to assess intention tremor are the finger-to-nose and heel-to-shin tests. In a finger-to-nose test, a physician has the individual touch their nose with their finger while monitoring for irregularity in timing and control of the movement. An individual with intention tremors will have coarse side-to-side movements that increase in severity as the finger approaches the nose. Similarly, the heel-to-shin test evaluates intention tremors of the lower extremities. In such a test, the individual, in a supine position, places one heel on top of the opposite knee and is then instructed to slide the heel down the shin to the ankle while being monitored for coarse and irregular side-to-side movement as the heel approaches the ankle.
   Section::::Causes and effects.
   Sural nerve (SN) stimulation results in a reflex that is both phase and intensity dependent. The sural nerve innervates the lateral (outside) portion of the foot and could be activated during either the swing or stance phase when encountering uneven terrain. The intensity dependent response is indicative of the level of activation and, therefore, the potential for harm.
  
  1. During the swing phase, SN stimulation indicates encountering an obstacle on the lateral side of the foot. The reaction is to move the foot inward and the leg up, out of the way. Observed EMG responses are:
   The most common manifestation of ataxic cerebral palsy is intention (action) tremor, which is especially apparent when carrying out precise movements, such as tying shoe laces or writing with a pencil. This symptom gets progressively worse as the movement persists, causing the hand to shake. As the hand gets closer to accomplishing the intended task, the trembling intensifies which makes it even more difficult to complete.
   If the patient is making an honest effort, the examiner should feel the "normal" limb's heel extending (pushing down) against his or her hand as the patient tries to flex (raise) the "weak" leg's hip. Feeling this would indicate an organic cause of the paresis. If the examiner does not feel the "normal" leg's heel pushing down as the patient flexes the hip of the "weak" limb, then this suggests functional weakness (sometimes called "conversion disorder"), i.e. that effort is not being transmitted to either leg.
   Dysdiadochokinesia is demonstrated clinically by asking the patient to tap the palm of one hand with the fingers of the other, then rapidly turn over the fingers and tap the palm with the back of them, repeatedly. This movement is known as a pronation/supination test of the upper extremity. A simpler method using this same concept is to ask the patient to demonstrate the movement of trying a doorknob or screwing in a light bulb. When testing for this condition in legs, ask the patient to tap your hand as quickly as possible with the ball of each foot in turn. Movements tend to be slow or awkward. The feet normally perform less well than the hands. When testing for dysdiadochokinesia with speech the patient is asked to repeat syllables such as /pə/, /tə/, and /kə/; variation, excess loudness, and irregular articular breakdown are signs of dysdiadochokinesia.
   Section::::Signs and symptoms.:Associated conditions.
  
  The disorder is closely associated with developmental disabilities or autism. More recent studies have shown there is a strong link between prolonged RMD and ADHD.
  
  Section::::Causes.
   In mild cases, ET can manifest as the inability to stop the tongue or hands from shaking, the ability to sing only in vibrato, and difficulty doing small precise tasks such as threading a needle. Even simple tasks like cutting in a straight line or using a ruler can range from difficult to impossible, depending on the severity of the condition. In disabling cases, ET can interfere with a person's activities of daily living, including feeding, dressing, and taking care of personal hygiene. Essential tremor generally presents as a rhythmic tremor (4–12 Hz) that occurs only when the affected muscle is exerting effort. Any sort of physical or mental stress will tend to make the tremor worse.
   In the past the variation was attributed to random effects. A more recent interpretation is that sway has a fractal structure. A fractal pattern consists of a motif repeated at varying levels of magnification. The levels are related by a ratio called the fractal dimension. It is believed that the fractal pattern offers a range of fine and gross control tuning. Fractal dimension is altered in some motor dysfunctions. In other words, the body cannot compensate well enough for imbalances.
  
  Section::::Pathology.
   1. In normal, unimpeded walking, TN activation during the transition from stance to swing should decrease as the foot begins to leave the ground. In this case, increased TN stimulation would suggest scuffing of the bottom of the foot along the ground. The reflexive response will bring the foot up, pulling it off the ground. EMG responses to stimulation, again, help to explain how this is accomplished. 
  
  BULLET::::- Increased tibialis anterior activity produces dorsiflexion, raising the foot off the ground.
   The lateral side of the sole of the foot is rubbed with a blunt instrument or device so as not to cause pain, discomfort, or injury to the skin; the instrument is run from the heel along a curve to the toes (metatarsal pads). Many reflex hammers taper at the end of the handle to a point which was used for testing the plantar response in the past, however, due to the tightening of infection control regulation this is no longer recommended. Either a single use device or the thumb nail should be used.
  
  There are three responses possible:
   Historically, to temporarily alleviate symptoms, patients have tried positional maneuvers, such as tilting their head to one side or upside down, lie down on their backs, or sit in a chair with their head between their knees. Similarly, a routine of lying down four times per day with legs elevated to around 20 inches for at least two weeks has been attempted as well. Depending on the underlying cause of the disorder, the individual may need to remove caffeine from their diet, reduce exercise, or gain weight. It may be the case that the symptoms are induced by anxiety; anxiolytic drugs or supplements (e.g., GABA) combined with the removal of caffeine from the diet could offer a simple strategy to determine if anxiety is the root cause.
   Initial diagnosis often is made during routine physical examination. Such diagnosis can be confirmed by a medical professional such as a physiatrist, neurologist, orthopedic surgeon or neurosurgeon. A person with foot drop will have difficulty walking on his or her heels because he will be unable to lift the front of the foot (balls and toes) off the ground. Therefore, a simple test of asking the patient to dorsiflex may determine diagnosis of the problem. This is measured on a 0-5 scale that observes mobility. The lowest point, 0, will determine complete paralysis and the highest point, 5, will determine complete mobility.
   Section::::Signs and symptoms.
  