1. Motor System Fall 2012 Basal Ganglia Cerebellum
Neuro Exam of Motor System
UMN and LMN Signs
Cerebellum Lesions
Basal Ganglia Disorders
Fall 2012

2. Corpus Striatum Striatum – Caudate + Putamen
Lentiform Nucleus – Putamen + Globus Pallidus
Corpus Striatum – Caudate + Putamen + Globus Pallidus

3. Basic Connections

4. Direct Pathway

5. Indirect Pathway

6. Lobes Anterior lobe Posterior lobe Flocculonodular lobe Anterior lobe

7. Lobes
Flocculus
Nodulus
Anteroinferior View

8. Sagittal Subdivisions
Vermis
Paravermis
Lateral Hemisphere

9. Functional Organization

10. Vermal Spinocerebellum
Posture
Locomotion
Gaze

11. Paravermal Spinocerebellum
Reaching,
Grasping
Movements

12. Cerebrocerebellum
Motor Learning

13. Cerebellar Peduncles
SCP
MCP
ICP

14. Cerebellar Cortex
Granular layer

15. Cerebellar Cortex Connections
Afferents
Climbing fibers
Carry “training” information
Mossy fibers
Carry “state” information
Efferents
Purkinje cells
Deep cerebellar nuclei

16. Deep Cerebellar Nuclei
FGED

17. Muscle Appearance Atrophy Fasciculations Fibrillations
Profound or severe = LMN sign
Disuse = UMN sign
Fasciculations
LMN sign
Visible on surface of muscle
Fibrillations
Not visible to naked eye
Need EMG to detect

18. Muscle Tone Hypertonia Spasticity (UMN sign) Rigidity (BG sign)
Hypertonia and hyperreflexia
Primarily in anti-gravity muscles
Velocity dependent
Clasp-knife effect
Clonus often seen
Rigidity (BG sign)
Hypertonia with normal reflexes
Affects all muscles
Velocity independent
Lead-pipe rigidity
Cog-wheel rigidity

19. Muscle Tone
Hypotonia
LMN sign
Tone depressed
Muscle may be flaccid

20. Muscle Power / Strength
0 = No contraction
1 = Flicker or trace of contraction
2 = Active movement with gravity removed
3 = Active movement against gravity
4 = Active movement against gravity and resistance
5 = Normal strength

21. Reflex Grading 0 = Absent even with reinforcement
1 = Present, decreased amplitude and velocity
Elicited with reinforcement
2 = Normal amplitude and velocity
3 = Increased in amplitude/velocity with spread to adjacent sites
4 = Increased in amplitude/velocity with spread to adjacent sites and clonus

22. Definitions Plegia = total paralysis Paresis = motor weakness
Quadriplegia = all 4 limbs
Paraplegia = both legs or both arms
Hemiplegia = one side of body
Paresis = motor weakness
Quadriparesis = all 4 limbs
Paraparesis = both legs or both arms
Hemiparesis = one side of body

23. Lower Motor Neuron Signs
CN nuclei, ventral horn
Plegia (focal & severe)
Decreased DTRs
Decreased muscle tone
Flaccidity
Babinski sign not present
Clonus not present
Fasciculations often seen

24. Upper Motor Neuron Signs
CST system
Paresis (generalized)
Increased DTRs
Increased muscle tone
Spasticity
Babinski sign present
Clonus may be present
Disuse atrophy

25. Cortical Lesions M-I (Primary motor cortex) PMC (Premotor cortex)
Contralateral paresis
Worse for distal muscles
Pronator drift test
PMC (Premotor cortex)
No paresis
Apraxia of complex tasks
Perseveration

26. Cortical Lesions SMA (Supplemental motor area) No paresis
Can’t coordinate both sides
Difficulty learning new motor tasks

27. Cortical Lesions PMA (Parietal motor area) FEF (Frontal eye field)
No paresis
Apraxia
Difficulty with hand orientation
Astereognosia and agraphesthesia
Contralateral hemineglect
FEF (Frontal eye field)
Inability to gaze to opposite side
Gaze preference to side of lesion

28. Cerebellar Signs Ipsilateral to lesion Decomposition of movements
Ataxia (asynergia)
Dysmetria
Dysdiadochokinesia
Intention-tremor
Slow onset
Not UMN or LMN

29. Basal Ganglia Signs Contralateral to lesion Tremor-at-rest
Dyskinesia with hypertonia
Parkinson’s disease
Dyskinesia with hypotonia
Chorea
Athetosis
Ballism
Not UMN or LMN