Muscle tone.

 D efinition  H ow the muscle tone is maintained  A bnormal muscle tone  T ypes of AMT  P hysiotherapy management CONTENT

Muscle tone is a partial state of contraction of a skeletal muscle to maintain its optimal length during resting condition, even when a force is applied to elongate the muscle. It is accomplished by the asynchronous discharge of nervous impulse in the motor neurons in the anterior gray horn of the spinal cord. Clinically it may be defined as the resistance that is encountered when the joint of relaxed muscle is moved passively. Definition

Muscle tone is maintained by monosynaptic reflex which is known as stretch reflex. The stretch reflex may be passive or active. How the muscle tone is maintained

Clinically there may be manly two type of abnormaliy  Increase muscle tone or hypertonia  Decrease muscle tone or hypotonia. Hypertonia: This condition exists when the muscle tone is increased it occurs when lesion exists that involve supraspinal centres or their descending tract but not the corticospinal tract. There are two types of hypotonia: Spasticity Rigidity Abnormal muscle tone

SS pasticity Spasticity may be defined as a velocity dependent increase in resistance to passive stretch of a muscle with exaggerated tendon reflex. C linical features C linical significance RR igidity Another abnormality associated with increased force is rigidity.which can occures in different forms.Rigidity occurs with a variety of acute and subacute brainstem disorders and consists of opisthotonus clenched jaws and stiffly extended limbs.

There are two types of rigidity  Spastic rigidity: In UMNL it is due to the hyperactivity of dynamic(gama 1) fusimotor fiber.  Cog-wheel rigidity: In parkinsons disease it is due to hyperactivity of static(gama 2) fusimotor fiber. Clinical feature Clinical significance

This condition exists when the muscle tone is diminished or absent. It occurs when any part of the monosynaptic stretch reflex is interrupted. Without this two main type of AMT,there may be another type of AMT such as spasm,tremor,athetosis,chorea,dystonia,myoclo nus etc. Hypotonia

 Movement and handling: Manual stretching  Assisted or passive movement:  Weight bearing  Modulation of muscle tone  Positioning and sitting  Splinting  Equipment: Electric and patient propelled wheelchair Gymnastic balls Thermal treatment eg.ice,hot pack Electrical stimulation Hydrotherapy Physiotherapy management of abnormal tone