|
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
|
