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Primary Motor Cortex

  • The image descriptionprimary motor cortex (M1, or somatomotor area) occupies a large portion of the precentral gyrus (Brodmann area 4) and typically executes movements that are selected and planned by other areas of the brain.
An image showing the lateral and sagittal view of the brain
An image showing the Primary Motor Cortex colored and labeled, lateral and sagittal view of the brain
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  • image descriptionEach hemisphere has a primary motor cortex and both are organized by body region or somatotopically.
An image showing the Lateral view of the right hemisphere and Coronal view of the right hemisphere
An image showing the Primary Motor Cortex highlighted and labeled, Lateral view of the right hemisphere and Coronal view of the right hemisphere
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  • The medial and superior portions image descriptioncontrol the actions of the feet, legs, trunk, and hands.
  • The lateral portions image descriptioncontrol the actions of the head, mouth, and throat.
An image showing the Primary Motor Cortex highlighted and labeled, Lateral view of the right hemisphere and Coronal view of the right hemisphere
An image showing the Primary Motor Cortex (highlighted and labeled) controlling feet,legs,trunk and hands, Lateral view of the right hemisphere and Coronal view of the right hemisphere
An image showing the Primary Motor Cortex (highlighted and labeled) controlling feet,legs,trunk, hands, head, mouth and throat, Lateral view of the right hemisphere and Coronal view of the right hemisphere
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  • The primary motor cortex on one side of the brain controls the muscles on the opposite side of the body.
  • Nerve cell image descriptionimpulses (or action potentials) exit the motor cortex via upper level neurons, which cross over at the medulla pyramids.
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing the action potential moving from the right cerebral cortex to left side muscles through the spinal cord
An image showing left side muscles contraction after receiving an action potential from the right cerebral cortex to left side muscles through the spinal cord
An image showing left side muscles contraction after receiving an action potential from the right cerebral cortex to left side muscles through the spinal cord
An image showing left side muscles contraction after receiving an action potential from the right cerebral cortex to left side muscles through the spinal cord
An image showing left side muscles contraction after receiving an action potential from the right cerebral cortex to left side muscles through the spinal cord
An image showing the pathway of the primary motor cortex, passing through medulla and spinal cord ending with the target muscle
  • The axons then enter the spinal cord as a part of the corticospinal tracts. Lower level neurons carry impulses from the ventral horns of the spinal cord to the skeletal muscles.

Overview:

Test yourself image showing the pathway of the primary motor cortex (1. Motor Cortex 2. Medullary pyramids 3. Spinal cord) numbered and without answers
Test yourself image showing the pathway of the primary motor cortex (1. Motor Cortex 2. Medullary pyramids 3. Spinal cord) numbered and answered below
Swipe to show/hide the answers
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