The biceps reflex

I think everyone is familiar with the word reflex. Today, the editor is not talking about the reflex you think. Do you know the biceps? Maybe you don’t understand what I am going to say now, but you will know it in a moment. Reflex is not only a phenomenon, but also a means of case analysis through reflex. Next, I will popularize the basic knowledge of biceps reflex to let you better understand what is biceps reflex and what its significance is.

1Normal value

The normal response is contraction of the biceps brachii.

2 Clinical significance

Abnormal results: The normal deep reflex of the biceps brachii is transmitted by the musculocutaneous nerve, passes through the cervical spinal cord 5-6, and is still transmitted by the musculocutaneous nerve. Abnormal biceps reflex suggests damage to the above reflex arc.

People who need to be examined: patients with suspected musculocutaneous nerve damage.

3. Notes

Unsuitable groups: patients with arm disabilities or injuries.

Taboos before examination: Relax your arms before examination.

Requirements for examination: The examination can be conducted in supine or sitting position.

4 Inspection process

(1) Supine examination method: The patient lies on his back with his forearms semi-flexed, muscles relaxed, and hands placed on the abdomen. The examiner presses the biceps tendon slightly above the elbow joint with the left thumb, and then taps the thumb with the percussion hammer held in the right hand. Normally, this causes the forearm to flex.

(2) Examination in the sitting position: The patient sits, and the examiner supports the patient's elbow with his left hand and his forearm with his left forearm. Then, he presses his left thumb on the patient's biceps tendon and taps the thumb with a percussion hammer. Under normal circumstances, the reaction is the same as above.

During the examination, if the above reactions are hyperactive, weakened or absent, they are all abnormal biceps reflex.

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Triceps reflex:

The patient's upper arm is abducted and the forearm is semi-flexed. The examiner holds the patient's elbow with his left hand.

Then the percussion hammer is tapped directly above the olecranon

The triceps tendon,

The response is a contraction of the triceps and a slight extension of the forearm.

The reflex center is in the 6th and 7th segments of the cervical spinal cord.

Radial periosteal reflex:

The patient's forearm is semi-flexed and semi-pronated, and the examiner taps the radial styloid process with a percussion hammer. The normal response is flexion of the elbow and pronation of the forearm. The reflex center is in the 5th and 6th segments of the cervical spinal cord.

Knee jerk:

When the patient sits, the calf is completely relaxed and hangs down at right angles to the thigh. In supine position, lift both knee joints with your left hand to bend the calf to 120 degrees.

Then use the percussion hammer held in the right hand to tap the quadriceps tendon.

The normal response is calf extension. If the patient is too nervous,

If the reflex is not present, ask the patient to clasp his hands.

Pull it tight and try again to pull it out. The reflex center is in the 2nd to 4th segments of the lumbar spinal cord.

reflection

Seat inspection

Supine examination

reaction

Reflex Arc

Biceps tendon reflex

The patient's forearm is semi-flexed and internally rotated. The doctor supports the front of his hand with his left hand, places his left thumb on his biceps tendon, and supports the back of his hand with his left upper arm. Hold the percussion hammer in your right hand and tap your left thumb lightly.

The patient's forearm is semi-flexed and internally rotated, with the hand placed on the abdomen. The doctor tapped the biceps tendon with his left fingers

Contract the biceps and flex the elbow.

Myocutaneous

Musculocutaneous nerve

Triceps tendon reflex

The patient's forearm is semi-flexed and internally rotated. The doctor held his forearm with his left hand and tapped the triceps tendon above his olecranon.

The patient's forearm is semi-flexed and internally rotated, with the hand placed on the abdomen. The doctor lifted his elbow slightly with his left hand and tapped the triceps tendon above the olecranon.

Triceps contraction, forearm extension

Radial nerve

Cervical spinal cord segments 6-7

Radial nerve

Knee tendon reflex

The patient sits upright with the heel naturally on the ground, so that the thigh and calf form an obtuse angle, or one leg is placed on the other and the quadriceps tendon under the patella is tapped lightly.

The doctor supported the patient's popliteal fossa with his left hand, brought the knee joint into a semi-flexed position, and gently tapped the quadriceps tendon. Medicine is all there. Line provided

The quadriceps contract and the calf extends.

Femoral nerve

Lumbar spinal cord segments 3-4

Femoral nerve

Achilles tendon reflex

The patient sits upright with the heels on the ground, the thigh and calf forming an obtuse angle, and the knee slightly abducted. The doctor holds the sole of the foot with his left hand and slightly dorsiflexes it. Tap the eye tendon gently.

The lower limbs are placed in a semi-flexed and externally rotated position or the patient lies prone with the knees bent and the calves upright. The doctor holds the sole of the foot with his left hand, slightly dorsiflexes it, and gently taps the Achilles tendon.

The gastrocnemius contracts and flexes toward the plantar surface of the foot.

Tibial nerve

Lumbar spinal cord 5 -

Sacral cord segments 1-2

Tibial nerve

1. Weakened or absent reflexes: seen in damage to any part of the spinal cord reflexes, such as peripheral neuritis, lesions of the anterior horn cells of the spinal cord (gray matter inflammation), and acute lesions of the brain or spinal cord resulting in brain or spinal cord shock (acute injury). In addition, bone, joint, and muscle diseases may also cause weakened or absent reflexes.

2. Hyperreflexia: seen in upper neuron damage and spinal tract lesions (such as cerebral hemorrhage, cerebral embolism and brain tumor). The spinal reflex is released due to the loss of control of higher-order neurons. In addition, when the excitability of the nervous system is generally increased, such as in neurosis, hyperthyroidism, obstruction, etc., bilateral symmetrical hyperreflexia may also occur.

The above is an analysis of the biceps reflex. I believe you have a deeper understanding of this phenomenon. Reflex is not only a theory. The information fed back through reflex plays a very important role in our treatment of diseases.