Where in the CNS

Question 1

How do UMN and LMN lesions present? [4]

+ Babinski’s Sign + one more Upper Limb stuff

Answer 1

UMN: function of modulating reflex arc

• hyperreflexia, Brisk reflexes
• Tone increased
• Upward plantar
• • Pronator Drift

LMN: part of reflex arc

• no reflexes
• hypotonia
• Denerving muscles: muscle wasting, fasciculations
• Downward plantar

Question 2

What signs do Cord lesions (CNS) give

Answer 2

Cord lesions (CNS) can give both UMN and LMN signs

• LMN at the level of lesion due to Anterior horn cell of LMN
• UMN signs lower than the level of lesion

Question 3

Distinguish location of lesion of power vs quantity movement issues;

Answer 3

Power - Weakness - Motor Axis; EXCLUDING CEREBELLUM

• think of Cerebral Hemispheres
• think of Brainstem

Quantity - perceived as weakness - but is Cerebellum + Basal Ganglia issue

Question 4

Name all components of the CNS:

Answer 4

Brain

• Cerebral Cortex, Hemispheres, Basal Ganglia
• Cerebellum
• Brainstem

Spinal Cord
- Corda Equina

Question 5

Give all functions, cranial nerves of the sub components of the

• Cerebral Hemispheres [3]
• Brainstem [3]

Answer 5

Cerebral Hemispheres

• Grey matter @ Cortex - higher cognitive functions, arithmetic, language, speech, AWARENESS
• White matter - “wires” - purely motor/ purely sensory
• Grey matter @ Basal Ganglia - Movement quantity, learning, emotion;

Brainstem

• Midbrain - CN 3 4
• • Vertical Gaze center - riMLF
• Pons - CN 5; 6 7 8 (pontomedullary)
• • Horizontal Gaze center - PPRP
• Medulla - CN 9 10 11 12

BS: also

• Reticular formation - consciousness, BREATHING
• Cerebellum connections
• Longitudinal tracts

Question 6

Important cord levels and plexuses

Answer 6

C 3 4 5 - phrenic nerve!!! - breathing
C 5678 T1 - Brachial plexus
T12 - L4 – Lumbar Plexus
L 1234 S1234 - Lumbosacral plexus

S 234 - Pelvic Splanchnic nerve

Question 7

What 2 structures to localize for UMN lesion and how are they different in presentation

Answer 7

UMN found in

• Brain
• Spinal Cord
• Hemiparesis + Hemiplegia - UNILATERAL
• Paraparesis + Quadraparesis + Spincteric involvement
  + LMN sign at level of lesion;

Question 8

What clinical signs in cauda equina lesions

What is cauda equina

Answer 8

Spinal cord ends at L1
L2 onwards to L5, S1-S5, CCG1
- all spinal nerves, PNS;

• Gives LMN presentations!
• • Downward Plantars
• Paraplegia + Sphincteric involvment (as seen in Cord Lesions) - hence LMN lesion giving paraplegia that is not Spinal Cord Lesions;

Question 9

Gimme 2 localizations of paraplegia + spincteric involvement and how to differentiate

Answer 9

Spinal Cord CNS OR Cauda Equina PNS

• Spinal Cord presents UMN lesion below the level
• Cauda Equina all presents LMN lesion cos spinal nerves - PNS

Question 10

Gimme ALL structures and functions of the BS again

Answer 10

Reticular Formation - consciousness, BREATHING
Gaze centres - Horizontal riMLF, Vertical PPRF
Longitudinal tracts - Motor, Sensory
Cerebellum connections - Ataxia
Sympathetic outflow, Cranial nerves

Question 11

Difference between Stroke w consciousness and Stroke without consciousness

Answer 11

Stroke without consciousness means Brainstem reticular formation affected;

Question 12

Where is diplopia localized to

Answer 12

Brainstem!

Question 13

Brainstem lesion all possible presentations

Answer 13

Unconscious, Stop breathing

Diplopia - GAZE issue - gaze for coordinated eyes

Horner syndrome

Cranial Nerve deficits (LMN)

Hemiparesis/Hemiplegia

Vertigo, Ataxia

Question 14

Brainstem vs Cerebral Hemispheres defects

- Compare [1] and Contrast [2]

Answer 14

Both should have hemiparesis

Cerebral Hemispheres

• Cognitive issues
• Visual field defects VS Diplopia

Question 15

Cerebral Cortex - Grey Matter

- Lobes, Areas and their functions

Answer 15

Frontal Lobe
- Precentral gyrus for Primary Motor Cortex
- LEFT Broca’s Area for speech production
Parietal Lobe - Postcentral gyrus for Primary Sensory Cortex

Temporal Lobe

• Hippocampus for memory
• Wernicke’s Area - LEFT superior temporal gyrus; for language and comprehension
• Superior temporal gyrus also has Primary Auditory Cortex

Occipital Lobe
- Primary Visual Cortex @ Calcarine Sulcus KIV

Question 16

Cortex cognitive functions and their medical names for problems

• note is white matter

Answer 16

Recognition: Agnosia
Arithmetic: Dyscalculia
Language: DysphaSia
Awareness: Neglect - hemispatial neglect without vision problems;

Question 17

Cerebellum functions and lesion presentation

• Localization within cerebellum
• Lesion location presentation!

Answer 17

Eyes: Nystagmus, Broken Pursuit
Precise movement lost
- Cerebellar Dysarthria
- Finger nose dysmetria
- Truncal Ataxia
- Heel Shin Ataxia 

Intention Tremor

NOTE ATAXIA can be found w BS lesions too;
Presentation: Ipsilateral! Vermis is more truncal less limbs than hemisphere

Question 18

Contralateral and Ipsilateral distribution for

• Cortex
• Brainstem Pons wrt CN5, CN7
• Brainstem Medulla wrt CN7
• Cerebellum

Answer 18

Cortex
- all contralateral: Face and Body as decussation is lower

BS Pons wrt CN7

• Contralateral Face, lower half; Contralateral Body
• UMN of CN7 gone, hence Contralateral
• UMN of body gone

BS Pons wrt CN5
- LMN CN5 gone - ipsilateral face;

BS Medulla wrt CN7

• Ipsilateral Face, ENTIRE face; Contralateral Body
• UMN of body gone; LMN of CN7 gone

Cerebellum

• both ipsilateral;
• if vermis is more truncal less limbs;

Question 19

What’s pronator drift

Answer 19

UMN lesion

- pronator muscles stronger than supinator