Tendon reflex, also known as deep reflex, actually refers to the non-independent muscle contraction that occurs when tendons are rapidly stretched. It is actually a type of muscle stretch reflex (the other being muscle anxiety). The conduction of tendon reflexes through chemical fibers has a relatively large diameter (12 to 20 μm) and a fast transmission speed (above 90 M/s). Tendon reflexes are monosynaptic reflexes, with a very short danger period on the reflex surface (about 0.7 ms). For example, the knee reflex involves striking the quadriceps tendon below the patella, causing the quadriceps muscle to contract once.

Tendon reflexes are monosynaptic reflex surfaces of the body. The effector of the tendon reflex is the muscle spindle, with the central nervous system located in the anterior horn of the spinal cord, and the effector is mainly fast muscle tissue with rapid contraction. If the tendon reflex is weakened or fades away, it indicates damage to the reflex arc, and if the reflex is hyperactive, it indicates disease in the superior central nervous system. Clinical medicine often uses tendon reflexes to understand the function of the central nervous system.

Definition of tendon reflexes

Tendon reflexes (tendon reflex) are also known as phase-dependent stretch reflexes, referring to the sudden contraction of related muscles caused by striking tendons. It is usually determined by the level of muscle contraction on both sides of the body to identify whether a particular tendon reflex is increased (more excited), decreased, or faded away. Changes in tendon reflexes in clinical medicine have diagnostic significance and are a common examination item for the central nervous system [1].

Characteristics of tendon reflexes

Tendon reflexes are monosynaptic reflex surfaces, primarily produced by the rapid contraction of fast muscle fibers within the muscle. Commonly examined tendon reflexes in clinical medicine include: biceps reflex, triceps reflex, radius reflex, knee reflex, achilles reflex, etc. Tendon reflexes are a key clinical symptom for the localization of central nervous system damage. The level of tendon reflexes can be described as disappearance (-), weakened ( ), normal ( ), increased ( ), or clonic ( ).

Reflex examination method

On the tendons of the proximal and distal bones, the reflex surface is quickly struck with a reflex hammer to elicit it.

(1) Biceps muscle tendon reflex

The operator uses the thumb to press the tendons of the biceps muscle slightly above the wrist joint,敲击the thumb, resulting in the flexion of the upper arm.

If the reflex is hyperactive, decreased, or fades away, it is a physiological change.

(2) Triceps muscle tendon reflex

The best method to examine this reflex surface is to lie on the back: the wrist joint slightly flexed at an oblique angle, the upper arm at an oblique angle to the body axis outside the costal arch, the arm close to the upper edge of the diaphragm. The operator holds the arm tightly and敲击the upper part of the triceps muscle slightly above (1.5-2 cm above the olecranon), reflecting the straightening of the upper arm. Another method is for the patient to extend the arm and flex the wrist joint, use the reflex hammer to敲击the tendons of the triceps muscle, and the operator holds the patient’s hand with the right hand, releasing the pressure to cause the upper arm to straighten.

This reflex surface of practical vaccines belongs to physiological reflexes, and an abnormality may occur if it is more excited or decreased, or fades away.

(3) Reflex surface of the radius sheath

During the examination of clinical symptoms with vaccines, the patient’s wrist joint should be flexed at an oblique angle or slightly acute, with the hand position close to the middle of pronation and supination. The operator’s right hand supports the left hand of the patient, and the reflex hammer敲击the styloid process of the radius, reflecting wrist flexion, pronation, and finger flexion.

The production of practical vaccines may cause damage to the brachialis, triceps, pronator, and biceps muscles, resulting in a weakened or消退 of this reflex surface.