Decreased muscle tone

I don't know what muscle tone is. In fact, to put it simply, it is the force generated by the mutual traction of muscle cells, which leads to muscle relaxation, so this problem occurs. Generally, there are various types of muscle tone and different bases, so there are many postures. Some examinations reveal that they have weakened muscle tone, but they don't understand what this performance is, which makes them feel particularly uneasy.

Muscle tension, simply put, is the force generated by muscle cells pulling on each other. The tension of a muscle when it is at rest and relaxed is called muscle tone. Muscle tone is the basis for maintaining various body postures and normal movements, and manifests itself in many forms.

When a person lies down to rest, the tension in the muscles of various parts of the body is called resting muscle tension. When the body stands, although there is no obvious muscle contraction, the front and back muscles of the body also maintain a certain tension to maintain the standing posture and body stability, which is called postural muscle tension. The tension of muscles during exercise is called motor muscle tension, which is an important factor in ensuring continuous and smooth muscle movement (without tremors, twitches, or spasms).

Grading

Passive Movement (PROM) Muscle Tone Grading Criteria

Ⅰ Mild

Resistance occurs during the last quarter of the PROM, when the muscle is in its longest position.

Ⅱ Moderate

Resistance appears at 1/2 of the PROM.

III Severe

Resistance occurs during the first quarter of the PROM, when the muscle is in its shortest position.

Modified Ashworth grading system

Level 0

Normal muscle tone.

Level 1

Slightly increased muscle tone: passive flexion and extension of the affected part with minimal resistance at the end of the joint range of motion, or sudden catching and release.

Level 1+

Mild increase in muscle tone: Sudden catching in the last 50% of the joint range of motion, followed by minimal resistance in the last 50% of the joint range of motion.

Level 2

A significant increase in muscle tone: Muscle tone increases significantly through most of the joint's range of motion, but the affected part can still be moved relatively easily.

Level 3

Severely increased muscle tone: Passive movements are difficult.

Level 4

Stiffness: The affected part becomes stiff when it is passively flexed or extended and cannot move.

Causes and mechanisms

Decreased muscle tone may occur in various myopathies, myasthenia gravis, peripheral neuropathy, radiculitis or cerebellar damage. Blockage of the nerve fibers that transmit proprioception in the spinal cord can also cause a decrease in muscle tone. In children with acute hemiplegia, they may have low muscle tone in the early stages of paralysis, and then increased muscle tone and enhanced tendon reflexes may occur after a few days or weeks. Paroxysmal or intermittent hypotonia may occur in familial periodic paralysis, stenoses, and atonic seizures of epilepsy. Pyramidal system diseases cause increased muscle tone. The muscle tone of extrapyramidal system and basal ganglia lesions may be reduced or increased, sometimes manifesting as increased gear-like muscle tone. During decerebrate rigidity, muscle tone increases significantly, the limbs become rigid, the lower limbs are extended, the upper limbs are flexed, and the head is tilted back.