 DEFINITION: It includes all fibers that can influence the motor end plate activity and do not pass in the pyramidal tract.

 Functions of the Extrapyramidal system: 1-Regulation and integration of voluntary motor activity. 2-Regulation and maintenance of the muscle tone. 3-Regulation and maintenance of emotional and associative movements.

 Disturbance of the functions of the extra- pyramidal system leads to:

II-Disturbance in the regulation and maintenance of normal muscle tone resulting in: III-Disturbance in the regulation and maintenance of emotional and associated movements resulting in:

 It is due to deficiency of dopamine in the basal ganglia and substantia nigra.

*- Causes : I- Idiopathic: Parkinson's disease (paralysis agitans). The cause is unknown.

II- Symptomatic: There is a known cause which leads to deficiency of dopamine in the brain,but without structural changes in the substantia nigra or basal ganglia.

1- Inflammatory: 2- Vascular: 3- Toxic: 4- Neoplastic: 5- Traumatic:

I-Tremors:-

Mask-Face -Bent Posture- Gorilla like Pill- rolling Short steppage – Shuffling gait Parkinson’s patient

II- Rigidity :-

III-Loss of emotional and associative movements: - - IV-Other clinical manifestations may be found in some cases (mainly post-encephalitic):

* By far the commonest causes of Parkinsonism are: 1) Paralysis agitans. 2) Post-encephalitic. 3) Atherosclerosis.

- The manifestations of Parkinsonism are due to an imbalance between the levels of acetylcholine and dopamine in the basal ganglia and substantia nigra.

I- Anticholinergic drugs:.

II-Levo-Dopa: (Dopamine precursor):

III_Levo-Dopa + Carbi-Dopa: (Sinemet)

* On and off phenomenon: After long term treatment with L-dopa the patient may show signs a Parkinsonism (under treatment) alternating rapidly with signs of drug overdosage, mainly Chorea (over treatment),as if being turned "on and off." The dose of L-dopa should be reduced and other drugs as Bromocriptine are given.

III-Dopamine agonist- IV-Amantadine hydrochloride (Symmetrel): V- Surgical : 1) Pallidectomy or 2) Thalamotomy

 DEFINITION: Chorea is involuntary, static, irregular, dysrhythmic, sudden, jerky, pseudopurposive movements of any part of the body, including the face, trunk and/or limbs.

 This a condition where there are: * Involuntary, irregular, static, slow, snake-like movements. They involve the extremities (especially the hands & fingers) and the face on each side.

* This is a condition where there are: * Involuntary, static, very slow, torsion or twisting like movements. * They involve the neck, trunk & the proximal muscles of the extremities

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