Neuro examination

Question 1

What are the different types of mentation?

Answer 1

alert
• normal response to environmental stimuli
disorientated/confused
• abnormal response to environment
depressed/obtunded
• inattentive, less responsive to environment
stuporous
• unconscious but can be roused by painful stimuli
comatose
• unconscious and unresponsive to any environmental stimuli

Stupor and comatose = more brainstem
Depressed either FB or BS

Question 2

What sort of abnormal behaviours are there?

suggestive of forebrain

Answer 2

• aggression
• compulsive walking/circling
• loss of learnt behaviour
• vocalisation
• hemineglect syndrome – animals with structural forebrain lesions ignore half of their environment (contralateral)

Question 3

What is decerebrate rigidity?

Answer 3

 extension of all limbs and opisthotonus
 release of inhibitory UMN descending pathways on LMNs
 lesion – rostral brainstem
 usually stuporous or comatose

Question 4

What is decerebellate rigidity?

Answer 4

 hyperextension of TLs and opisthotonus
 loss of inhibition of stretch reflex mechanism of antigravity muscles
 lesion – rostral part of cerebellum
 mentation normal; may be episodic or postural
HLs normal

Question 5

What is Schiff Sherrington?

Answer 5

 hyperextension of TLs (maintaining voluntary movement and normal CP) and paralysis of PLs
 interference with Border cells – inhibitory neurons in
cranial lumbar spinal cord that inhibit the TL extensor muscles
 thoracic or cranial lumbar spine
 not prognostic factor but only occurs in serious injuries

Question 6

Outline sensory/ spinal ataxia

Answer 6

 usually more subtle
 due to decreased sensory information arriving from the limbs to tell CNS where they are in space at any given time
 “legs just don’t know where they

Question 7

What is vestibular ataxia

Answer 7

 loss of orientation of the head with the eyes, neck, trunk and limbs and results in loss of balance
 typically with leaning, falling, rolling towards side of lesion

Question 8

What are the grades of spinal lesions?

Answer 8

Grade 1 no deficits, just pain
Grade 2 paresis, ambulatory
Grade 3 paresis, non-ambulatory
Grade 4 paralysis
Grade 5 no pain sensation

Question 9

How do postural reactions work?

Answer 9

information from proprioceptors (joints, tendons and muscles – GP; inner ear – SP)
→ forebrain ( for conscious perception of information)
 problem could be in nerves, spinal cord, all of brain, everywhere!!!

Question 10

Outline the panniculus/ cutaneous trunci reflex

Answer 10

→ pinching of skin
→ sensory information enters the spinal cord approximately 2 vertebral spaces cranially
→ ascends to C8‐T1
→ bilateral synapse with motor neurons of lateral thoracic nerve
→ brachial plexus
→ cutaneous trunci muscle
→ bilateral contraction of these muscles

useful for T3-L3 lesions and brachial plexus lesions (bad px indicator for brachial plexus lesions)

Question 11

Outline the palpebral reflex

Answer 11

 touch medial and/or lateral canthus of eye → blink
 input → Trigeminal (V) ophthalmic and maxillary brainstem
 output → Facial (VII)

Question 12

How does a spinal reflex tell you if the lesion is UMN or LMN

Answer 12

UMN - increased/ the same

LMN - decreased/ absent

Question 13

Outline the corneal reflex

Answer 13

 lightly touch cornea → blink and eye globe retraction
 input – Trigeminal (V) ophthalmic, brainstem
 output:
 Abducens (VI) → globe retraction
 Facial (VII) → blink
 useful as same input as palpebral

Question 14

Outline physiological nystagmus

Answer 14

 input – vestibulocochlear (VIII) and brainstem
 output:
 Oculomotor (III)
 Trochlear (IV)
 Abducens (VI)
 when reduced/lost - most commonly due to raised ICP

Question 15

Why should you turn an animal upside down/ move head when assessing nystagmus?

Answer 15

 you’re challenging the vestibular system by changing the position of the head
 look for evoked (rather than static):
 strabismus
 nystagmus

Question 16

Outline the menace

Answer 16

• menacing gesture, covering other eye → blink (careful no wind)
• input – Optic (II)
• forebrain, cerebellum, brainstem
• output – Facial (VII)
• not a reflex – learnt response; present from 10-12 wks

Question 17

Outline the gag reflex

Answer 17

 open mouth or touch pharynx → contraction of pharynx
 input – Glossopharyngeal (IX) and Vagus (X), brainstem
 output – Glossopharyngeal (IX) and Vagus (X)