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 precentral gyrus 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 precentral gyrus, 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. Cortical motor area controls the musculature on the opposite side of the bodyCortical 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 movementCortical 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)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 areaBoth individual muscles and movements are represented in M1 area Cells in cortical motor area are arranged in columnsCells in cortical motor area are arranged in columns PRIMARY MOTOR CORTEX

8. CORTICOSPINAL ( PYRAMIDAL TRACT ) Motor signals are transmitted directly from the motor cortex to the spinal cord through corticospinal tracts

9. 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

10. 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

11. DR FAWZIA AL-ROUQ

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

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

14. FUNCTIONS OF EXTRA PYRAMIDAL SYSTEM OR MULTINEURONAL SYSTEM REGULATION OF BODY POSTURE, INVOLVING INVOLUNTARY MOVEMENTS OF LARGE MUSCLE GROUPS OF TRUNK AND LIMBS

15. 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

16. 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 (3 rd, 4 th, 5 th, 6 th, 7 th, 9 th, 10 th, 11 th and 12 th ) In the spinal cord they include the anterior horn motor neurones and their axons, i.e. the motor nerves to skeletal muscles

17. UMN lesions and LMN lesions

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