What Is a Knee Jerk Reflex?

The afferent nerve is the femoral nerve, the center is in the lumbar spinal cord 2 to 4, and the efferent nerve is the femoral nerve. The weakened or disappeared knee reflex is most commonly found in spinal cord or peripheral neuropathy, and is one of the signs of paramotor motility. It is more common in myopathy, cerebellum, and extrapyramidal diseases. Hyperreflexia is a sign of paralysis of upper motor neurons. It can be seen in hyperthyroidism, tetanus, low calcium convulsions and excessive mental stress.

Abnormal knee reflex

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The afferent nerve is the femoral nerve, the center is in the lumbar spinal cord 2 to 4, and the efferent nerve is the femoral nerve. The weakened or disappeared knee reflex is most commonly found in spinal cord or peripheral neuropathy, and is one of the signs of paramotor motility. It is more common in myopathy, cerebellum, and extrapyramidal diseases. Hyperreflexia is a sign of paralysis of upper motor neurons, seen in hyperthyroidism,

The patient is supine, the examiner supports the patient's part with his left hand or forearm, the hip joint and knee joint are flexed at an obtuse angle, and the heel should not leave the bed surface, so as not to affect the reflex motion and difficult to obtain correct results. The examiner tapped the quadriceps tendon with his right hand holding a percussion hammer, and the calf straightened. In the sitting position, the calf is fully relaxed and sagging at right angles to the thigh, and the quadriceps tendon at the lower knee is tapped, and the reaction is calf extension. Increased leg reflexes are more common in pyramidal lesions, and hyperreflexia of the knee can often be accompanied by palatal clonics.

(1) Peripheral neuritis Peripheral symmetry of the distal part of the limb develops from sensory and dyskinesias from the distal end to the proximal end with burning-like pain and tenderness in the lesion area. In the symmetry of distal limbs, motor neuron paralysis, decreased muscle tone, muscle atrophy, autonomic dysfunction, hyperhidrosis or anhidrosis, etc., tendon reflexes are reduced or disappeared, and ankle reflexes are reduced earlier than knee reflexes.

(2) Guillain-Barre's syndrome has a history of upper respiratory tract infection, symmetrical ascending flaccid paralysis, and the distal end is heavier than the proximal end. In severe cases, breathing can be caused by intercostal and diaphragmatic muscle paralysis. Often accompanied by cranial nerve involvement, transient paraesthesia or hyperalgesia, significant muscle tenderness in the distal extremities, weakened or disappeared tendon reflexes, and negative pathological reflexes. Cerebrospinal fluid showed white-cell separation after 2 weeks.

(3) Progressive myodystrophy belongs to recessive recessive inheritance. It is almost entirely male, and it is rare for females. It started to be obvious between 3 and 6 years old, and gradually became worse. The inability to drive dry and the proximal parts of the extremities started, and the lower limbs were heavier than the upper limbs. Difficulty walking and climbing stairs, pelvic instability when walking, Gowers sign appeared when standing upright, about 90% of cases began to show gastrocnemius pseudohypertrophy, that is, the volume increased without muscle strength, gradually after 6 years of age Accompanied by muscle atrophy and contracture. The tendon reflex first decreases, and finally the knee tendon reflex disappears when the muscle atrophy reaches a serious level, but in the early stage of pseudohypertrophy, the tendon reflex can be active.

(4) Periodic paralysis This disease usually occurs in children to young people. It is often caused by full meals and intense activities, cold and emotional excitement. More than onset at night, limb symmetry was found when waking up in the morning. The typical attack begins at the lower back and the proximal lower extremities and spreads to the distal lower extremities. Expansion can also affect the upper limbs and neck muscles. Hyperhidrosis, dry mouth, oliguria, constipation, and muscle swelling are common in the early stages of an attack. Examination revealed flaccid paralysis, reduced or disappeared knee tendon reflexes. The diseased muscles are full and firm, they feel normal, and they have a clear consciousness. Generally, serum potassium is only slightly reduced, and the potassium content in urine is significantly reduced.

(5) Epidemic myalgia symptom occurs frequently in children and adolescents, with rapid onset, fever, sore throat, and headache, and pain and tenderness in lower chest and upper abdominal muscles soon appear. Breathing, coughing, and exertion become more intense, sometimes mainly affecting the neck, back, and shoulders, or weakened knee reflexes and skin irritation. Some patients may be accompanied by mild meningoencephalitis symptoms such as apathy, dizziness, photophobia, and strong neck. Enteritis, myocarditis, orchitis can also occur.

(6) Optic neuromyelitis (ophthalmoneuromyelitis, neuro-optic myelitis) Have a history of epidemiological illness before onset, acute or subacute onset, blurred vision on one side, and gradually developed on both sides. Vision is low, orbital or posterior orbital pain, and some appear beforehand. Two to three months later, the limbs became numb, paralyzed or quadriplegia. The field of vision is concentrically reduced, blind or quadrant blind. At first, muscle strength was reduced, tendon reflexes were reduced or disappeared, and diaphragmatic reflexes were still bilateral extensors. Later, muscle tone increased, knee tendon reflexes were hyperactive, and pathological reflexes were positive. Sensory loss usually rises to the mid-thoracic segment. Loss of sensation and autonomic dysfunction below the lesion level, accompanied by autonomic dysfunction, abnormal sweating, and dysuria.

(7) Congenital-muscularmaldev-elopment is an infantile myopathy, which is autosomal recessive, or dominant. See both sexes. When the sick child was born, there was a decrease in muscle tone and muscle weakness, which was obvious in the limbs and trunk muscles. Some of the patients were unable to stand upright, and they could not sit or stand upright. The knee tendon reflexes and limb tendon reflexes decreased or disappeared. No pseudohypertrophy. Most courses do not progress, and some may have muscle atrophy. Severe cases with respiratory effects. May be associated with joint contractures, or have congenital bending of most joints.

(8) Familial autonomic dysfunction This disease mostly occurs in infants and young children, and the symptoms are variable. If the lacrimal gland is secreted little or lacking, the excitement obviously causes the blood pressure to rise, and it is easy to cause the blood pressure to drop when standing. Cold hands and feet, red skin, fast breathing, elevated body temperature, swallowing and speech disorders, accompanied by diarrhea or constipation, paroxysmal vomiting, excessive or no saliva, low muscle tone, uncoordinated movements, biceps, brachialis The triceps and knee tendon reflexes disappear, are not sensitive to pain, are emotionally agitated, and have low intelligence. The body is often accompanied by left-right asymmetry and deformity.

(9) Pellagra (pellargra, pellagrosis, chichism) Slow onset, concealment and long course of disease. In the early stage, it is often tiring, weak, anorexia, tongue pain and so on. This was followed by diarrhea, glossitis and lack of gastric juice. Erythema and dermatitis appear on the exposed part of the body. Neurasthenia-like symptoms in the early stages are often overlooked, followed by memory impairment, lack of desire, or mania, depression, and usually manifested as dementia at the end. The most common posterior lateral cord damage is manifested by stiffness in the lower limbs, ataxia, hyperreflexia of the knee tendons, and Babinski sign positive. Deep sensory disturbance. Symmetrical peripheral neuropathy is mainly caused by limb pain. Loss of vision and diplopia can occur, as well as tinnitus, dizziness, and facial paralysis.

(10) Hematoporphyria (hematoporpnyria, porpnyria) is mainly pain in the lower limbs, paralysis of the muscles at the distal end of the limbs, and carpal ptosis. No sensory disturbance, the knee tendon reflex disappeared. Sometimes it has quadriplegia, and the upper limbs are characterized by its upper limbs. The upper limbs are often paralyzed from the extensor muscles. Eyelid drooping, diplopia, difficulty swallowing, hoarseness, and difficulty breathing. There may also be seizures, unconsciousness, and coma. Accompanied by headache, fatigue, insomnia and irritability. Emotional instability, mental disorders, mania, depression, hallucinations, etc. Severe abdominal pain due to gastrointestinal smooth muscle spasm.

(11) Nodular arteritis (arteritis nodosa) is symmetrical. It is obvious at the distal end of the limb, showing paralysis of the limb, sensory disturbance, and disappearance of knee tendon reflexes. Some manifestations are single neuritis with asymmetric limb motor sensory disturbances. Paralysis is more common than sensory loss and often causes symptoms of encephalitis, such as headache, vomiting, disturbance of consciousness, tortuous fundus veins, papillary edema, Retinal artery thrombosis or nodules. Hemiplegia, aphasia, blindness, localized epilepsy, and extrapyramidal symptoms can occur. There may also be weakness in both lower limbs, muscle atrophy, muscle weakness, and muscle tenderness.

(12) Alcoholic polyneuritis The onset is generally slow, but there are also those who have acute onset within a few days. The lower limbs of the sensory movement disorder are prominent, the paralateral muscles of the lower leg are paralyzed, and the rear muscles of the lower leg or quadriceps can also be affected. It showed flaccid paralysis, the knee tendon reflex disappeared, muscle atrophy, and skin edema, thin skin, dry and dull skin, cold or bruising, pigmentation, nail changes, hair loss and other autonomic changes. Muscle contracture may occur in the late stage of muscular atrophy, and gastrocnemius muscles are tender.

(13) Syringaomyeli (syringaomyeli) More men than women, more onset in 20 to 30 years old. Onset is slow, often from the base of the horn after the neck is enlarged, so the early symptoms are often pain in the corresponding dominating area of the ipsilateral upper limb, loss of temperature, and the sense of touch and deep sensation are relatively retained. Patients' local skin is often burned without feeling . The cavity expanded to anterior gray joint with bilateral segmental dissociative pain and temperature dysfunction (in the form of a short coat). The area of sensory loss has spontaneous indescribable burning pain, which is persistent and is called "central pain". After the forward angle is expanded, muscle atrophy and muscle twitching will occur in the corresponding segment. If the cavity is swollen in the neck, the small muscles in both hands will be atrophic. The upper arm brachial and triceps tendon reflexes were reduced or even disappeared. When invading the spinal cord and thalamus, the contralateral skin pain and loss of temperature sensation below the damage plane. When the pyramidal tract is damaged, the spastic paralysis of the ipsilateral limbs below the plane of the diseased side and hyperflexion of the knee tendon. Due to malnutrition, joint swelling is called cnarcot joints.

(14) Poliomyelitis (poliomyelitis) Paralysis is inferior motor neuron, it is flaccid, muscle tension is low, and knee tendon reflex is weakened. Paralyzed muscle groups are asymmetrically distributed, varying in severity. It is common in the lower limbs, and the upper limbs are rare. Paralysis of the proximal large muscle group appears earlier and heavier than the distal small muscle group. It can affect the neck and back muscles, but cannot stand up, sit up and turn over. If the cervical, thoracic and spinal cords are involved, the diaphragm and intercostal muscles (respiratory muscles) are paralyzed, affecting respiratory movement. Slow breathing, nasal tremor, low voice, intermittent speech, weak cough, paralysis of the abdominal muscles, sneezing, rectal abdomen muscle contraction when coughing, and may have refractory constipation, urinary retention or incontinence.

(15) Cerebellar ataxia The patient swings or deviates forward or backward or side to side when standing, the two feet are often separated, and the eyes are aggravated when closing the eyes. In patients with unilateral cerebellar disease, the head and trunk are biased toward the diseased side, and they tend to fall over to the diseased side. When walking with eyes closed, turn on the side of the disease. Muscle tone of the limbs on the affected side decreased, and a counterattack occurred due to insufficient antagonism. Tendon reflexes are reduced, and knee reflexes can be pendulum-like. The head and neck are biased toward the diseased side, and sometimes the eyes are slightly tilted toward the healthy side. Occasionally, detached strabismus is seen, and large horizontal nystagmus. The ataxia of the lip, tongue, and laryngeal muscles of the vocal organs causes slow speaking, ambiguity, intermittent sound, and frustration and explosiveness.

(16) Cerebral ataxia (cerebrumataxia) is mainly a disorder of body balance, gait instability, and dumped backward or to one side. Frontal ataxia, in addition to ataxia on the contralateral limb of the lesion, is often accompanied by hyperflexion of the knee reflex and other tendons, increased muscle tone, positive Babinski sign, Kadock sign, and mental symptoms and strong grip Reflex isofrontal damage symptoms. The parietal lobe lesions show different degrees of ataxia on the contralateral affected limb. The symptoms are obvious when the eyes are closed, and the deep sensory disturbance is not serious or transient. Temporal lobe lesions appear with transient balance disorders. Cerebral ataxia is less associated with nystagmus.