Upper and Lower Motor Neuron
Upper and Lower Motor Neuron
Upper and Lower Motor Neuron
MOTOR NEURON
FUNCTION AND LESION
CNS influence the activity of
skeletal muscle through two
sets of neuron
• Upper motor neuron
• Pyramidal tract
• Extra pyramidal tract
PYRAMIDAL TRACTS
•corticospinal tract
EXTRAPYRAMIDAL TRACTS-
•Reticulospinal Olivospinal
•Vestibulospinal
•Tectospinal
•Rubrospinal tract
•Corticobulbar tract
•Corticorubral tract
Nerve pathways
Descending Tracts
Tract Signal function
Fine voluntary motor control of the limbs. The
Corticospinal (pyramidal) pathway also controls voluntary body posture
adjustments.
Involved in involuntary adjustment of arm position in
Rubrospinal response to balance information; support of the body.
Regulates various involuntary motor activities and
Reticulospinal (1) Pontine assists in balance (leg extensors). Some pattern
movements e.g. stepping
(2) Medullary Inhibits firing of spinal and cranial motor neurons,
control of antigravity muscles.
It is responsible for adjusting posture to maintain
Vestibulospinal (1) Medial balance (neck muscles).
(2) Lateral It is responsible for adjusting posture to maintain
balance (body/lower limb).
Controls head and eye movements, Involved in
Tectospinal involuntary adjustment of head position in response to
visual information.
Descending Pathways
• Babinski sign(corticospinal)
.
• weakness with no muscle atrophy
• Muscle hypotonicity
• Fasciculations
• BULBAR PALSY
• is a similar disorder as psedobulbar palsy but
is caused by lower motor neuron lesions