Equine Neurological Exam

Question 1

Describe the relationship between white and grey matter in the brain..

Answer 1

White - inside

Grey - outside

Question 2

Describe the relationship between the position of white and grey matter in the spinal cord…

Answer 2

White - outside

Grey - inside

Question 3

Of what is grey matter composed?

Answer 3

Cell bodies (nuclei) of neurons

Question 4

Of what is white matter composed?

Answer 4

Myelinated neurons

Question 5

Why does white matter appear white?

Answer 5

Myelin is fatty

Question 6

Examination of which characteristics provide information about the forebrain?

Answer 6

Mentation and behaviour

Question 7

Stringhalt is the colloquial term for what?

Answer 7

Extreme hock and stifle hyperflexion

Question 8

Describe the clinical signs associated with cerebellar dysfunction…

Answer 8

Spastic/exaggerated movements
Absence/diminished menace response
Intention tremor
Ataxia without weakness

Question 9

What comprises the brainstem?

Answer 9

Pons
Medulla
Reticular formation
Ascending proprioceptive pathways
Descending motor pathways
Cranial nerve nuclei

Question 10

Why might weakness and ataxia be associated with a brainstem lesion?

Answer 10

The brainstem contains ascending proprioceptive pathways and descending motor pathways

Question 11

What is the afferent limb involved in the pupillary light reflex?

Answer 11

Optic nerve

Question 12

What is the efferent limb involved in the pupillary light reflex?

Answer 12

Parasympathetic fibres in the oculomotor nerve (CNIII)

Question 13

Describe the pathway involved in the menace response..

Answer 13

Optic nerve - Optic chiasm - Thalamus - Opposite occipital cortex - Facial nerve and nuclei - Cerebellum

Question 14

How is vision best assessed in the horse?

Answer 14

Walking a horse around and between obstacles

Question 15

Which cranial nerves control eye position?

Answer 15

Oculomotor (III)
Trochlear (IV)
Abducent (VI)

Question 16

Describe the retractor oculi reflex

Answer 16

Retraction of the globe when pressing on the cornea through the eyelid

Question 17

Outline the classic signs of cerebral disease…

Answer 17

Head pressing
Yawning excessively
Behavioural changes
Head turns
Generalised seizures

Question 18

What is the role of the reticular formation?

Answer 18

To alter the level of consciousness

Question 19

Where would you localise a lesion causing cranial never problems, ataxia and paresis?

Answer 19

Brainstem

Question 20

Define nystagmus

Answer 20

Regular, uncontrolled movements of the eye within the socket

Question 21

Horizontal nystagmus is a classic sign of….

Answer 21

Peripheral vestibular disease

Question 22

Vertical nystagmus is a classic sign of…

Answer 22

Central vestibular disease

Question 23

What therapy would you provide for a horse unable to blink?

Answer 23

Sub-palpebral lavage

Question 24

Which cranial nerve provides afferent limb of the retractor oculi reflex?

Answer 24

Trigeminal (CNV)

Question 25

Which cranial nerve provides the efferent limb of the retractor oculi reflex?

Answer 25

Abducens (VI)

Question 26

Motor dysfunction of which cranial nerve would result in the muscle atrophy of the mastication muscles?

Answer 26

Trigeminal (CNV)

Question 27

Motor and sensory dysfunction of which cranial nerve would result in the lack of response and lip droop?

Answer 27

Trigeminal (CNV)

Question 28

Describe ptosis...

Answer 28

Weakness of the eyelid (lashes point down vertically)

Question 29

Which cranial nerve provides pharyngeal and laryngeal function?

Answer 29

Glossophargyneal (IX) | Vagus (X)

Question 30

What is Horner's syndrome?

Answer 30

Interruption of the sympathetic pathway between the hypothalamus and the eye

Question 31

Outline the clinical signs of Horner's syndroe...

Answer 31

``` Ptosis Miosis Enopthalmus Prominent third eyelid Conjunctival hyperaemia Sweating ```

Question 32

What controls the amount horses sweat?

Answer 32

Blood flow to the sweat glands

Question 33

Define ataxia

Answer 33

A functional deficit associated with defective proprioception

Question 34

What nerves supply the neck?

Answer 34

Vertebral

Question 35

Outline how ataxia can appear in the horse...

Answer 35

Hypermetria Hypometria Dysmetria Truncal sway

Question 36

What sensory organs are responsible for proprioception?

Answer 36

Muscle spindles | Golgi tendon organs

Question 37

What is the purpose of UMNs?

Answer 37

Control muscles

Question 38

What is the purpose of LMNs?

Answer 38

Contract muscles

Question 39

Give the key distinction between the appearance of ataxia vs lameness in the horse

Answer 39

Ataxia is irregularly irregular where as lameness is regularly irregular

Question 40

What type of tail pull would you use to assess LMNs?

Answer 40

Standing

Question 41

What type of tail pull would you use to asses UMNs?

Answer 41

Walking

Question 42

Describe UMN weakness in the horse...

Answer 42

Inability to control muscles Normal/increased tone No muscle atrophy

Question 43

Describe LMN weakness in the horse...

Answer 43

Inability to contract muscles Flaccidity Muscle atrophy (if chronic)

Question 44

Which diagnostic tools could be used to ascertain if lameness is caused by muscle weakness?

Answer 44

CK and AST measurements