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The patient keeps his forearm half-flexed, then the examiner holds the patient's elbow joint with his left hand and presses the biceps muscle with the left thumb. The examiner holds the reflex hammer with his right hand and slams his left thumb(as shown in the picture). The normal reaction is a rapid upward bending of the patient’s forearm. If the above reaction is hyperactive, weakened or disappeared during the examination, the biceps reflex is abnormal.
The afferent nerve reflected by the biceps muscle is the sensory fiber in the musculocutaneous nerve, and the reflex center is the gray matter of the cervical vertebrae 5-6; The efferent nerve is the somatic motor fiber of the musculocutaneous nerve, and the effector is the biceps. Abnormal reflection indicates that the reflex arc is damaged. Common symptoms include arm muscle strain, arm muscle atrophy, intramuscular muscle atrophy, arm stretching pain, and complete function loss of hand.
The patient bends the elbow joint, then the examiner holds the patient’s forearm with his left hand and uses the percussion hammer to hit the triceps tendon above the olecranon (As shown in photo). The normal reaction is that the triceps contracts and the elbow joint turns straight. The reflection center of the triceps reflex arc is cervical vertebrae 5-6, which is transmitted by the sacral nerve. The abnormal reflex indicates that the biceps reflex arc is damaged and common symptoms include arm muscle weakness or muscle atrophy.
If the patient is in a sitting position, keep lower legs naturally sag, or place one leg on the lap of the other. When examined in a supine position, the examiner holds the patient’s knee joint with one hand and bends it by about 120°, and then slams the muscle under the kneecap with a percussion hammer(showing as following). Normal reaction is that the calf kicks ahead rapidly. This reflex is usually affected by the high-level part of the central nervous system. The strength and slowness of the reaction can reflect the functional status of the central nervous system. The knee reflex weakened or disappeared most commonly exist in the spinal cord or peripheral neuropathy, which is one of the signs of the lower motor neuron paralysis. It is more common in myopathy, cerebellum and extrapyramidal diseases. Hyperreflexia is a sign of upper motor neuron, occurs in hyperthyroidism, tetanus and low-calcium convulsions, sometimes excessive mental stress can also cause.
The patient is in supine with hips and knees bent, keeping the thighs slightly outward and externally rotated. The examiner holds the front of the patient's foot in one hand and bend it back, then use the hammer to attack the achilles(As picture shows). The normal reaction is that the gastrocnemius contracts and the foot flexed to the face. If the reflexion is extremely hyperactive, it is often accompanied by a hernia, which often suggests a pyramidal lesion. When the sciatic nerve is damaged, the lumbar disc is prolapsed, the sciatic neuritis or the sacral nerve is paralyzed, the tendon reflex will weaken or disappear.
The patient keeps his forearm semi-flexible and the back of the hand slightly ahead. The examiner holds the forearm with his left hand and allows the wrist to hang naturally, then slams the styloid process of radius with a percussion hammer(As shown in picture). The normal reaction is elbow bent and forearm ahead. If it is found that the flexion of the forearm is not obvious, but the finger flexes, then maybe the periosteal reflex is inverted.
The occurrence of inversion is caused by the contraction force of the active tendon becoming smaller, stimulation spreads after the afferent of anterior horn of the spinal cord, which causes the contraction of the antagonistic muscle; The paralysis of the active muscle which leads to the stretch reflex of the antagonist muscle may also influence. Related symptoms include upper cervical medullary lesions, complete cervical spinal cord injury, cervical spinal epidural lesions, and cervical spinal cord demyelinating lesions.