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MOTOR SYSTEM

MOTOR SYSTEM. MOTOR. THE WORD MOTOR MEANS M O V E M E N T. MOTOR SYSTEM INCLUDES. MOTOR CORTEX PYRAMIDAL TRACTS CORTICO SPINAL CORTICO BULBAR EXTRA PYRAMIDAL TRACTS BASAL GANGLIA CEREBELLUM. Primary (Somatic) Motor Cortex.

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MOTOR SYSTEM

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  1. MOTOR SYSTEM

  2. MOTOR THE WORD MOTOR MEANS M O V E M E N T

  3. MOTOR SYSTEM INCLUDES • MOTOR CORTEX • PYRAMIDAL TRACTS CORTICO SPINAL CORTICO BULBAR • EXTRA PYRAMIDAL TRACTS • BASAL GANGLIA • CEREBELLUM

  4. Primary (Somatic) Motor Cortex • Located in the precentralgyrus of each cerebral hemisphere. • Contains large neurons (pyramidal cells) which synapse on skeletal muscles • Allowing for voluntary motor control. • These pathways are known as the corticospinal tracts or pyramidal tracts.

  5. PRIMARY MOTOR CORTEX • Primary motor cortex (M1) lies in the frontal lobe in precentralgyrus, also called Broadmanns area 4 Important points regarding primary motor area: • Feet are at the top of the gyrus and face at the bottom • Arms and the hand area in the mid portion • Facial area is represented bilaterally, but rest of the representation is generally unilateral

  6. PRIMARY MOTOR CORTEX • Cortical motor area controls the musculature on the opposite side of the body • Cortical representation of each body part is proportionate in size to the skill of that part being used for fine voluntary movement • Therefore the area involved in hand movement and in speech have large representation in the cortex (more than half of primary motor cortex) • Both individual muscles and movements are represented in M1 area • Cells in cortical motor area are arranged in columns

  7. CORTICOSPINAL TRACTS OR PYRAMIDAL TRACTS • 80 % cross in the medulla Lateral corticospinal tract • 20 % do not cross in medulla Ventral or anterior (They cross in spinal cord) Corticospinal tract

  8. FUNCTIONS OF CORTICOSPINAL TRACT • LATERAL CORTICOSPINAL TRACT: • Fine movements of fingers that is skilled voluntary movement • VENTRAL CORTICOSPINAL TRACT: • It may be concerned with control of bilateral postural movements

  9. EXTRA PYRAMIDAL SYSTEM DR FAWZIA AL-ROUQ

  10. EXTRA PYRAMIDAL SYSTEM DEFINATION • Tracts other than corticospinal tracts are known as EXTRA PYRAMIDAL TRACTS.

  11. COMPONENTS OF EXTRAPYRAMIDAL SYSTEM • BASAL GANGLIA • BRAINSTEM Giving rise to following tracts: • Rubrospinal tract • Vestibulospinal tract • Reticulospinal tract • Tectospinal tract

  12. FUNCTIONS OF EXTRA PYRAMIDAL SYSTEMORMULTINEURONAL SYSTEM • REGULATION OF BODY POSTURE, INVOLVING INVOLUNTARY MOVEMENTS OF LARGE MUSCLE GROUPS OF TRUNK AND LIMBS

  13. IMPORTANT • Complex and overlapping function exist between Pyramidal and extra pyramidal systems for example while doing fine work like needle work (Pyramidal system) one has to subconsciously assume a particular posture of arms( extra pyramidal system) that enables to do your work

  14. Performance of normal voluntary movement, the integrity of two sets of neurons is important • Upper motor neurones • Neurons originating in the cerebral cortex and the brain stem • Synapse directly or indirectly with the anterior horn cells or with the motor neurones of the cranial nerves • Grouped into pyramidal and extrapyramidal systems • Lower motor neurones • Motor cranial nuclei and their axons, i.e. motor fibres of the cranial nerves (3rd, 4th, 5th, 6th, 7th, 9th, 10th, 11th and 12th) • In the spinal cord they include the anterior horn motor neurones and their axons, i.e. the motor nerves to skeletal muscles

  15. UMN lesions and LMN lesions

  16. LMN lesions • weakness, paralysis • flaccidity, hypotonia • Hypo- /no tendon • reflex • - Babinski sign • muscle atrophy • fasiculationof • involved muscle • UMN lesions • weakness, paralysis • spasticity • tendon reflexes • + Babinski sign • little,if any,muscle atrophy • no fasiculation

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