Lecture 2: Equine Nervous system: the examination Flashcards
what are the limitations of neurological exams
- Subtle changes in personality or mentation may be impossible to detect
- Ranges of normal with age and breed
- Sedatives affect results
Mental awareness is a function of the ___
Higher centers in the brain
Voluntary movements are initiated where
Cerebral cortex
Where is the ascending reticular activating system located
Throughout the medulla, midbrain, thalamus
What is the most common location of progressive stupor
Thalamus
Sensory information from the body travels via the ___to the cortex
Ascending reticular activating system
A head tilt is nearly always indicative of ___
Vestibular disease
Does the head tilt go towards the lesions or away from the lesion
Towards
What direction nystagmus fast phase and slow phase go towards
Fast phase away from the lesion, slow phase towards the lesion
A head turn is indicative of __ and __ disease
Cerebral and thalamic
What is Schaffer-Sherrington syndrome
Forelimb extensor rigidity without opsithotonus
What causes schiff-Sherrington syndrome
Acute severe thoracolumbar spinal cord disease
What is opsithotonus
Head and neck are in extreme extension
What type of opsithotonus occurs with midbrain disease
Decerebrate rigidity all four limbs have extensor rigidity
What type of opsithotonus occurs with cerebellar disease
Decerebrate rigidity- just forelimbs have extensor rigidity, intention tremors
What are some signs of spinal ataxia
Base wide stance, knuckling, sway, dog-tracking
Where is the lesion localized with mentation changes
Cerebral
Where is the lesion localized with intention tremors
Cerebellar
Where is the lesion localized with ataxia and no mental change
Spine
Where is the lesion localized with ataxia of hind limbs alone
Thoracolumbar/sacral spine
Where is the lesion localized with ataxia of front limbs and hind limbs (up to a grade worse)
Cervical spine
Where is the lesion localized with ataxia of front limbs worse than hind limbs
Thoracic intumescence
Cranial nerves innervate structures on the ___side of the head
Same/ ipsilateral
Central control of these cranial nerves comes from the ___cerebral cortex
Opposite/ contralateral
All CN originate from the brain stem except __ and __
1 and 2
What does olfactory nerve control and is it motor, sensory or both
Smell
Sensory
What does the optic nerve do and is it sensory, motor or both
Vision
Sensory
What does the oculomotor nerve do and is it sensory, motor or both
Eye movements, pupillary constriction, orbicularis oculi (eyelid muscle)
motor
What does the trochlear nerve do and is it motor, sensory or both
Eye movements
Motor
What does the trigeminal nerve do and is it motor, sensory or both
Facial sensation, mastication
Sensory and motor
What does the abducens nerve do and is it motor, sensory or both
Motor
Eye movements
What does the facial nerve do, motor, sensory or both
Facial expression, lacrimal and salivary glands
both
What does the vestibulocochlear nerve do and is it motor, sensory or both
Sensory
Hearing and balance
What does the glossopharyngeal nerve do and is it motor, sensory or both
Sensory and motor
Sensory from tongue and pharynx, taste, baroreceptors and chemoreceptors, salivary glands
What does the vagus nerve do, motor, sensory or both
Motor and sensory
Autonomic functions of gut, cardiac inhibition, sensation from larynx and pharynx, swallowing
What does the accessory nerve do, motor, sensory or both
Motor
Shoulder and neck muscles
What does the hypoglossal nerve do
Motor
Movements of tongue
If both vision and PLR is abnormal where are the lesions
Optic nerve lesion or primary eye issue
If the vision is affected but PLR is normal where is lesion
Cortical lesion
Where is the lesion if vision is normal but PLR is abnormal
Efferent arms lesions
What is SNS innervation to the eye responsible for
Dilation of the pupil, retraction of third eyelid, retraction of upper eyelid and rostral protrusion of the globe
What causes horners syndrome
Caused by disruption of SNS innervation to the globe/ peri orbital area
What are some clinical signs of horners
Ptosis, miosis, enophthalamus, protrusion of 3rd eyelid, sweating of ipsilateral face and cranial aspect of neck
Where are the horners syndrome lesions where there is sweating of the face and cranial neck ~C2
Guttural pouch and cranial cervical ganglion
Where are the Horners syndrome lesions where there is sweating of the face and neck ~C3-C4
Sympathetic trunk
Where is the Horners syndrome lesion if there is sweating down the shoulder ~T1
Thoracic inlet
What is anisocoria
Different sized pupils
With anisocoria, if you place in dark room and then expose to dim light and both pupils dilate to equal size then what is normal and what is wrong with originally dilated eye
Normal Sympathetic innervation
Dilated eye: CN III lesion
With anisocoria, if you place in dark room and expose to dim light if the pupils don’t dilate equally then what is abnormal and what is wrong with the smaller pupil (miosis)
Sympathetic innervation is abnormal
Smaller pupil: Horners
Hyper reflexive is ___motor neuron
Upper
Hypo reflexive is __motor neuron
Lower
Panniculus or cutaneous trunci reflex will be absent ___to the lesion
Caudal
What is the cervicofacial reflex
Tap along jugular groove and should get eye twitch and grimace
If the cervicofacial reflex is absent what is wrong
Local spinal cord or facial nerve deficits
What is the lordosis/kyphosis response
Braced indicates musculoskeletal pain
Deficit in perinatal reflex and anal tone indicates __
Cauda equine and sacral disease
What does the oculocephalic reflex test
CN 3, 4, 6 by moving head L to R and up and down
What is hypermetria
Excessive lifting of a limb, upper motor neuron
What is hypometria
Weakness and dragging, lower motor neuron
What is grade 0 spinal ataxia
Normal
What is grade 1 spinal ataxia
Extremely mild, performance limiting, professional has to perform multiple tests to determine dysfunction
What is grade 2 spinal ataxia
Mildly affected, easily appreciable to a professional, performance limiting
What is grade 3 spinal ataxia
Obvious to layperson, abnormalities notable at rest
What is grade 4 spinal ataxia
Severely ataxic, could fall during exam
What is grade 5 spinal ataxia
Recumbent to unable to stand
What is the normal cadence when cantering in a circle
3
How do neurological horses canter
Bunny hop or cross-canter
A poor response to a tail pull indicated what problem
Lower motor lesion at L3-L5
Walking a horse through obstacles like hills or curbs measures their ___
Functional proprioception
label 1-5 nerves
- Ulnar
- Musculocutaneous
- Median
- Tibial
- Peroneal
