Tract
Location of Upper Motor Neurons
Destination
Site of Crossover
Action
CORTICOSPINAL
 
Corticobulbar
 
Primary Motor Cortex (pyramidal cells)
Cranial Nerves III – XII
Brainstem
Conscious Motor control of skeletal muscles
 
Anterior (ventral) corticospinal
Primary Motor Cortex (pyramidal cells)
Lower motor neurons of anterior grey horns of spinal cord
Level of lower motor neuron
Conscious Motor control of skeletal muscles
 
Lateral corticospina
Primary Motor Cortex (pyramidal cells)
Lower motor neurons of anterior grey horns of spinal cord
Pyramids of medulla oblongata
Conscious Motor control of skeletal muscles
MEDIAL
 
Vestibulospinal
Vestibular nucleus (at pontomedullary junction)
Lower motor neurons of anterior grey horn of spinal cord
NONE
Subconscious regulation of balance and muscle tone
 
Tectospinal
 
Tectum (the superioir and colliculi of midbrain)
Lower motor neurons of anterior grey horn of spinal cord (cervical region only)
Brainstem
Subconscious regulation of muscles in head, neck and upper limb in response to auditory and visual stimuli
Reticulospinal
Reticular Formation of pons and medulla
Lower motor neurons of anterior grey horn of spinal cord
NONE
Subconscious regulation of reflexes
LATERAL
 
Rubrospianl
Red nuclei of the modbrain
Lower motor neurons of anterior grey horn of spinal cord
Brainstem (midbrain)
Subconcious regulation of limb muscle tone and movement

 

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