Muscle tone

Tone ( Latinized form of the Ancient Greek τόνος tonos " tension" to the verb τείνειν teinein "clamp on, relax ") is the " state of tension of the muscles ," which is caused by the viscoelastic properties of the tissue and by stimuli of the nervous system. There is also the "passive muscle tone " distinguished from " active muscle tone ."

In skeletal muscles ( striated muscle) it is primarily caused by alternating contractions of individual muscle fibers in the smooth musculature of the body interior is characterized by continuous contraction of muscle cells. The tone is dependent on the innervation through the nervous system, which can be carried out voluntarily or involuntarily, and the metabolic state of the muscle.

A prolonged, painful muscle tone is called tension. This condition occurs V.A. a one-sided posture and most commonly affects the neck and shoulder muscles.

Resting tone

All muscles have a certain resting tone. This tone generally characterized a force, in this case the force which opposes the muscle of a force acting externally on it. In muscle physiology, we find it, for example, in the stretching curves as mentioned, the function of the muscle length ( isolated muscle ) by the force ( the extensional weight), which is equal to the muscle tension ( reaction force ) is. Even a non-active, ie resting muscle is a stretching force against a voltage. After elongation is a short-term shift in the resting tension curve to the right possible (hysteresis).

These measurable even on isolated muscle tension must be distinguished from the so-called Reflextonus as involuntary Spannungstonus is tonic asynchronous active motor units, the neurogenic nature and may be different cause. Even in seemingly absolute inactivity contractions take place to some extent. These range from, for example, to pull in flaccid paralysis of the extensor muscles of a joint, the flexor muscles of that joint in flexion. This reflex resting tone due to a monosynaptic reflex and disappears only when the transection of the muscle innervating nerve or the nerve root.

There is a technical apparatus with which the depth of impression of a stamp is measured in the muscle surface at defined forces ( Myotonometer, Tissiu tensiometer ).

Orienting can also be assessed by palpating the muscle tension, such as in manual therapy.

Loss and increase

By destruction of the muscle nerves supplying or by poisons that the nerve-muscle interface ( motor end plate ) block (eg, curare ) may lead to a complete loss of muscle tone. This condition is referred to as paralysis or atony. The atony also occurs during REM sleep. Check the condition of reduced muscle tone is called hypotonia.

An increase of the tone is called hypertonia, which can manifest itself in the form of a cramp ( spasm ).