Somatic Motor System
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Somatic Motor system
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Overview of the Somatic Motor system
Praxis
Clinical signs related to the Somatic Motor system
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Somatic Motor system
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Overview of the Somatic Motor system
Praxis
Clinical signs related to the Somatic Motor system
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overview
Somatic
Motor
System
• Interactions of the sensory and motor
systems enable voluntary movement
• You have learned about these sensory
and motor pathways earlier in this class!
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Somatic
Motor
System
Internal motor systems (cerebellum &
basal ganglia) must be effective for
functional motor output to take place.
Exit circuitry (motor output pathways) also
must be effective for functional motor
output.
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corticoreticulospinal &
Corticoreticulospinal
vestibulospinal
Exit circuitry:
& Vestibulospinal
pathways
- control of trunk muscles; posture
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Exit circuitry:
corticospinal
Corticospinal
pathway
- finely tuned hand movements
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Exit circuitry:
corticorubrospinal
Corticorubrospinal
pathway
- limb movements
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Exit circuitry:
corticobulbar
Corticobulbar
pathway
- finely tuned movements
of the face & head
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Somatic Motor menu
Somatic Motor system
Overview of the Somatic Motor system
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Praxis
Clinical signs related to the Somatic Motor system
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praxis
Praxis
• The ability to produce a NEW motor response
• Describes earlier phases of the motor
learning process, NOT the execution of a
learned or practiced motor pattern
• Once a motor act is practiced & learned, it
NO LONGER requires praxis!
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Praxis
• Depends upon multisensory input
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Praxis
• Depends upon multisensory inputs
• Allows multiadaptive responses
in context
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Somatic Motor menu
Somatic Motor system
Overview of the Somatic Motor system
Praxis
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Clinical signs related to the Somatic Motor system
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Somatic Motor Clinical signs
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Clinical Signs
Signs
Position sense test
Clonus
Babinski sign
Enhanced deep tendon responses
Spasticity
Clasp knife response
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Position sense
Play
Movie
With the client’s eyes closed, the clinician manipulates the client’s
right thumb. He is asked to point his left thumb in the same direction
as his right thumb. The clinician switches sides and he is no longer
able to perform the task.
Clinical Signs
Signs
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Clonus
Play
Movie
A series of fast, involuntary contractions
symptomatic of damage to upper motor neurons.
Clinical Signs
Signs
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Babinski reflex
Play
Movie
An extension of the great toe, sometimes with fanning of the
other toes, in response to stroking of the sole of the foot. It is a
normal reflex in infants, but it is usually associated with a
disturbance of the pyramidal tract in children and adults.
Clinical Signs
Signs
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Enhanced Deep Tendon Reflexes
Play
Movie
An unusually vigorous patellar tendon reflex may be observed
following upper motor neuron damage, often in conjunction with
heightened muscle tone (spasticity) and clonus.
Clinical Signs
Signs
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Spasticity
Play
Movie
The man exhibits spasticity of the right side, while the woman
exhibits spasticity of the left side. Note the posture of the affected
arm, the swinging of the leg from the hip with reduced range of the
knee and ankle joints, and the reduced dynamic balance.
Clinical Signs
Signs
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Clasp knife response
Play
Movie
An animation of the concept, meant to illustrate an initially great
resistance to extension of the joint, followed by a gradual “melting” of
the resistance as continued, steady pressure is applied.
Clinical Signs
Signs
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That ends the
Somatic Motor system tutorial!
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Somatic Motor menu