SlideShare a Scribd company logo
HOW TO PERFORM A NEUROLOGICAL EXAMINATION NEUROLOGY
ON A CAT AND LOCALIZE THE LESION
Simon Platt, BVM&S, MRCVS, DACVIM (Neurology), DECVN
The nervous system plays a role in nearly all body processes. Disease syndromes may affect the central nervous
system (CNS), which includes the brain and spinal cord, and the peripheral nervous system, which includes
cranial nerves, spinal cord nerve roots, spinal nerves, peripheral nerve branches, and the neuromuscular
junction.
Suspicion of neurological dysfunction arises from the history and physical examination. The signalment,
presenting chief complaint, time course of clinical signs, and history may suggest the type of disease process or
species-specific disorder. A complete neurologic examination is necessary to localize the anatomic distribution,
to determine the severity of the disease process, and to assess the prognosis for patient recovery.
A neurological examination is easily integrated into a routine physical examination. The objectives of the
neurological examination are to confirm if there is a neurological abnormality and to specifically localize the
abnormality within the nervous system. In conjunction with the history, signalment, presenting complaint, and
the physical examination, the neurological lesion localization is a piece of a jigsaw essential to creating a list of
differential diagnoses for the disease. However, caution must be used as some manipulations necessary for the
neurological examination could exacerbate problems such as spinal cord disease.
Observation
Observation of the dog or cat is essential as it allows evaluation of the mentation, posture, attitude, and gait.
Changes in mentation (level and content of consciousness) are revealed by a history of personality change,
change in awareness of surroundings, and inappropriate behavioural responses. Consciousness is a function of
the brainstem (responsible for arousal) and the cerebral cortex (responsible for content and regulation). The
evaluation of the state of consciousness can classify the patient as depressed, demented or obtunded, delirious,
stuporous, and comatose.
Palpation
The musculoskeletal system should be palpated for asymmetry, masses, tenderness, and tone. A mass,
tenderness, or contour change requires further investigation. The vertebral column should be palpated for
deviations and pain being cautious not to apply too much pressure if suspicious of an instability. Unilateral
muscle mass loss or atrophy may indicate disuse if it is chronic or a neurogenic loss if it is acute (within seven
to 10 days).
Cranial Nerves
Cranial nerves have specific functions and evaluation of these functions can help to precisely locate a
neurological lesion due to their well-documented anatomy. The general functions and specific tests are
summarized in Table 1.
Simplistically, cranial nerve dysfunction may indicate a central nervous system (CNS) lesion (brainstem
disease) or a peripheral lesion (affecting the cranial nerves after they have exited the brainstem and course
through the skull). Evaluation of the cranial nerves should follow observation and palpation, with particular
attention paid to normal functions of eye movement, head movement, blinking, jaw and tongue movement, and
general symmetry of the head.
Initially an ophthalmic exam should be performed, which will assist with the evaluation of the optic (CN II),
oculomotor (CN III), trochelar (CN IV), and abducens (CN VI) nerves.
The following tests are essential to the evaluation of cranial nerve function:
The Menace Response
1. How to perform—obscure the vision in one eye and make slow threatening hand gesture toward the
other eye.
2. How to interpret—this is a learned response, not a reflex, to a perceived threat, which evaluates CNs II
and VII (responsible for innervation of the orbicularis oculi muscle which closes the eyelids), as well as
the central visual pathways and the cerebellum. Normal function is demonstrated by a blink or
retraction of the globe in response to the threat. To localize the lesion, other cranial nerve tests would
be required.
The Pupillary Light Reflex
1. How to perform—shine a bright light in each eye to evaluate the response of the pupil.
2. How to interpret—this is a reflex. Light is sensed by CN II; parasympathetic fibers of CN III cause
contraction of the iris muscle with direct and indirect simulation. The pupil is also innervated by
sympathetic fibres responsible for dilation, which have their origin in the thalamus and send fibres
down the cervical spinal cord to the T1-T3 spinal nerve roots before they ascend up the neck and
through the middle ear. A resting inequality in pupil size is termed anioscoria; to determine which pupil
is abnormal, the animal should be evaluated in the light and dark. In the dark, a sympathetic lesion will
mean the affected pupil will not be able to fully dilate. In the light, a parasympathetic lesion will mean
the affected pupil will not be able to fully constrict. Animals with sympathetic lesions will often
demonstrate miosis in accompaniment to third eyelid protrusion and enophthalmus, a condition called
Horner’s syndrome.
Evaluation of Strabismus
1. How to perform—observe the animal’s head in a normal position for a deviation of one or both globes
in the orbit(s).
2. How to interpret—cranial nerves III, IV, and VI aid vision by maintaining the globe in a central
position. Deviation of the globe from its central axis indicates dysfunction in one or more of these
nerves: ventrolateral—CN III, dorsolateral—CN IV, and medial—CN VI.
The Palpebral Reflex
1. How to perform—touch the medial canthus of the normal eyelid and watch response.
2. How to interpret—the normal eyelid should close. Cranial nerve V (trigeminal nerve) is responsible for
facial sensation, whereas the motor response to facial sensory stimulation is generally provided by the
facial nerve (CN VII). Facial paresis presents as a drooping of the facial muscles, most notably the lips
and the eyelids. It may also be detected as a reduction or absence in the blink response.
Evaluation of Jaw Tone
1. How to perform—observe patient for a dropped lower jaw and/or an inability to eat. Assess the
strength of the jaw safely by manually opening the mouth and evaluating the resistance to opening.
2. How to interpret—the mandibular branch of CN V provides motor function to the jaw. A dropped
lower jaw or the inability to chew can indicate damage to CN V.
The Oculocephalic Reflex/Physiological Nystagmus
1. How to perform—move the head from side to side in a horizontal plane and observe the resulting
movement of the eyes.
2. How to interpret—in normal animals, a physiological nystagmus will be induced, with the fast phase in
the direction of head movement. This reflex tests the integrity of CN VIII (vestibulocochlear nerve),
which is the sensory arm of this reflex, and CNs III, IV, and VI, which are responsible for the motor
movement of the eyes. Clinical signs of peripheral vestibular disease are manifest after damage to the
inner ear or vestibular branch of CN VIII, which effectively gives unbalanced input to the intact central
vestibular system. In the absence of head motion, spontaneous horizontal nystagmus is consistent with
CN VIII damage, with the fast component away from the side of the lesion. Unilateral peripheral
disease may cause a head tilt and circling to the side of the lesion.
Postural Reactions
The postural reactions are complex, requiring intact sensory and motor pathways throughout the nervous system
as well as unimpaired processing and integration in the brain. The complexity of the postural reactions allows
detection of minor deficits in any key component of the pathway. Postural deficits are seen caudal to or at the
level of the lesion. Additional testing must be performed to use the postural deficit to help localize the lesion
within the pathway of the deficit.
1. How to perform—a leg is placed in an abnormal position and a correcting response by the animal is
observed. Knuckling the toes over whilst supporting the body can be done to evaluate how long it takes
for the animal to correct. Alternatively, a piece of paper may be placed under each foot and slowly
moved sideways, to see if the animal returns its foot to the standing position. Other postural reactions
include wheelbarrowing, hopping, hemistanding, and extensor postural thrust.
2. How to interpret—conscious proprioception is the patient’s awareness of limb position and movement
without visual information. When the knuckling test is performed, an abnormality is indicated by a
delay or absence of the response. The sensory branch of proprioception is carried from the skin,
muscle, and joints of the leg through the spinal cord and brainstem to the sensory motor cortex, where
the brain responds by sending messages back to the lower motor neuron for motor function, resulting in
a rapid correcting foot placement. Ascending sensory pathways are located in the outermost regions of
the spinal cord and are very sensitive to compression. With minor spinal cord injury, proprioceptive
deficits may be present because of disrupted sensory pathways, while motor function persists because
the deeper motor tracts are unaffected. Both visual and tactile placing reactions require an intact motor
cortex and intact motor pathways to the involved limb. A cortical lesion may produce deficits in the
contralateral limb, whereas lower lesion produces deficits in the ipsilateral limb.
Spinal Reflexes
It is rare to have any reflex abnormalities if the animal has no evidence of gait abnormality, muscle mass loss, or
conscious proprioceptive deficits. In these cases, a complete reflex examination is unlikely to be helpful.
Completion of a reflex requires an intact sensory nerve that provides transmission to the spinal cord and an
intact motor nerve that elicits function from the innervated muscle. The reflex arc itself does not involve the
brain or the remainder of the spinal cord. Lesions in the motor arm of the reflex arc, termed lower motor neuron
(LMN), may cause a decreased or absent reflex (hyporeflexia or areflexia). An exaggerated response
(hyperreflexia) results from an interruption in proximal motor pathways that modulate the reflex, termed upper
motor neuron (UMN); however, stress or anxiety may cause an apparent increased reflex response, so it should
not be considered too important without other evidence of neurological disease. Lower motor neuron signs
indicate damage to one or more components of the reflex arc. Upper motor neuron signs indicate damage
anywhere between the reflex arc and the brain (Table 2). The most reliable reflex is the flexor withdrawal in the
thoracic and pelvic limbs. The other reflexes can appear to be present in small dogs just because the limbs will
move when struck with a reflex hammer irrespective of reflex function.
The Anal Sphincter Reflex
1. How to perform—pinch the anal sphincter with haemostats and watch for a wink-like contraction of the
external sphincter muscles and tail flexion.
2. How to interpret—this reflex reveals information regarding the pudendal nerve and caudal segments of
the spinal cord. A flaccid, unresponsive anus indicates LMN damage to the pudendal nerve or its spinal
roots. A hypertonic, hyperresponsive anal sphincter indicates UMN damage at any point cranial to the
pudendal nerve.
The Pedal Flexor Reflex
1. How to perform—apply a pinch stimulus to each foot and evaluate the response of the ipsilateral and
contralateral limb.
2. How to interpret—this is a withdrawal reflex in which stimulation of sensory receptors in the toes
elicits contraction of flexor muscle groups in the leg. Presence of a withdrawal reflex requires an intact
sciatic nerve (sensory and motor) and an intact spinal segment at the lumbosacral plexus, but does not
require transmission along the spinal cord to the brain. Absence of the withdrawal reflex in the pelvic
limb denotes extensive lower motor neuron damage involving the lumbosacral spinal cord segments
(L6-S2) as well as the nerve roots and the lumbosacral plexus; in the thoracic limb it denotes damage to
the cervical spinal cord segments (C6-T2), the spinal nerve roots and the brachial plexus.
The Patella Reflex
1. How to perform—a tap stimulus should be applied to the straight patella tendon and the response of the
limb should be evaluated. Reflex hammer size must be adapted to patient size for improved accuracy.
2. How to interpret—this is a myotactic (stretch) reflex that effectively stretches the quadriceps muscle.
This stretch stimulates the femoral nerve (L4-L5), which generates muscular contraction to extend the
stifle. Upper motor neuron lesions cause hyperreflexia and should be accompanied by weakness and
poor weight bearing. Disease in the L4-L5 spinal cord segments or nerves causes hyporeflexia.
Cutaneous Sensation and Pain
Cutaneous sensation testing provides information regarding the location and severity of a spinal cord or
peripheral nerve lesion. Evaluation of nociception (deep pain perception) is reserved for those animals showing
evidence of spinal cord disease based on abnormalities in gait, proprioception, and spinal reflexes. Lack of deep
pain sensation is a poor prognostic factor as it indicates severe nervous system damage. Nociception requires
cerebral perception of painful or injurious stimuli. It is important to remember that a withdrawal reflex is not an
indicator of pain perception and may be elicited in an animal whose spinal cord has been transected cranial to
the segment responsible for that reflex arc.
Hyperpathia is the sensation of pain produced by an innocuous stimulus such as palpating the vertebrae. All of
the cervical and thoracolumbar vertebra should all be palpated to detect focal points of hyperpathia which may
help localize the neurological lesion and will help with the differential diagnosis
Table 1. Cranial Nerves: Function and Applicable Tests
Cranial Nerve Nerve Function Applicable Tests
I Olfactory Smell i. Blindfold the animal and monitor
behavioural response to food
placed near nose; loss of smell
usually due to nasal disease rather
than neurological disease
II Optic Vision i. Menace response
ii. Pupillary light reflex
iii. Obstacle course
iv. Dropping cotton wool balls in
front of each eye
III Oculomotor Extrinsic and intrinsic ocular
muscles /upper eyelid muscle
i. Eyeball position
ii. Pupil size (mydriatic in disease)
iii. Physiological nystagmus
iv. Pupillary light reflex
IV Trochlear Extrinsic ocular muscles i. Eyeball position
V Trigeminal Facial sensation /jaw
movement
i. Palpebral reflex
ii. Jaw & masticatory muscle
palpation
VI Abducens Extrinsic ocular muscles i. Eyeball position
ii. Physiological nystagmus
VII Facial Muscles of facial expression /
parasympathetic supply to
lacrimal glands
i. Palpebral response
ii. Evaluation of facial symmetry
iii. Shirmer tear test
VIII
Vestibulocochlear
Hearing and balance i. Oculocephalic reflexes
ii. Assessment for head tilt
IX Glossopharyngeal Muscles of pharynx & larynx i. Gag reflex
X Vagus Muscles of larynx & pharynx i. Gag reflex
XI Accessory Superficial neck muscles i. None applicable
XII Hypoglossal Muscles of tongue i. Tongue grab/inspection
Table 2. Clinical signs associated with upper motor neuron (UMN)
and lower motor neuron (LMN) disease
Clinical Function UMN disease LMN disease
Motor function Paresis or paralysis Paresis or paralysis
Muscle tone Normal to increased Often reduced
Spinal reflexes Normal to decreased Decreased to absent
Muscle mass Normal to decreased (disuse
atrophy)
Dramatically decreased after five to
seven days (neurogenic atrophy)
Conscious proprioception Often reduced to absent Often reduced to absent

More Related Content

What's hot

Central nervous system vidhya
Central nervous system vidhyaCentral nervous system vidhya
Central nervous system vidhya
Teena Tanya
 
Issues in brainmapping...Neonatal EEG
Issues in brainmapping...Neonatal EEGIssues in brainmapping...Neonatal EEG
Issues in brainmapping...Neonatal EEG
Professor Yasser Metwally
 
Radiological pathology of brain developmental disorders
Radiological pathology of brain developmental disordersRadiological pathology of brain developmental disorders
Radiological pathology of brain developmental disorders
Professor Yasser Metwally
 
Neural tissue mobilization (Assessment)
Neural tissue mobilization (Assessment)Neural tissue mobilization (Assessment)
Neural tissue mobilization (Assessment)
Dr. Nithin Nair (PT)
 
Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...
Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...
Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...
Fundación Ramón Areces
 
hypotonia by Dr tadele teshome
hypotonia  by Dr tadele teshomehypotonia  by Dr tadele teshome
hypotonia by Dr tadele teshome
meriestop ethiopia
 
Module 4 cranial nerve
Module 4 cranial nerveModule 4 cranial nerve
Module 4 cranial nerve
Glance Ruiz
 
Principles of peripheral nerve repair
Principles of peripheral nerve repairPrinciples of peripheral nerve repair
Principles of peripheral nerve repair
Imran Javed
 
Neural tissue mobilization Upper Limb Assessment
Neural tissue mobilization Upper Limb AssessmentNeural tissue mobilization Upper Limb Assessment
Neural tissue mobilization Upper Limb Assessment
Dr. Nithin Nair (PT)
 
Neurological examination of vety patient.
Neurological examination of vety patient.Neurological examination of vety patient.
Neurological examination of vety patient.
Vikash Babu Rajput
 
Neurological exam lecture_notes
Neurological exam lecture_notesNeurological exam lecture_notes
Neurological exam lecture_notes
naveenkoval
 
neurodynamic-testing-and-neural-mobilization.pdf
neurodynamic-testing-and-neural-mobilization.pdfneurodynamic-testing-and-neural-mobilization.pdf
neurodynamic-testing-and-neural-mobilization.pdf
mupt77
 
Foot drop
Foot dropFoot drop
neural mobilization
neural mobilizationneural mobilization
neural mobilization
Nityal Kumar
 
Upper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdf
Upper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdfUpper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdf
Upper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdf
mupt77
 
Neurodynamics
NeurodynamicsNeurodynamics
Nerve Gliding Exercises - Excursion and Valuable Indications for Therapy
Nerve Gliding Exercises - Excursion and Valuable Indications for TherapyNerve Gliding Exercises - Excursion and Valuable Indications for Therapy
Nerve Gliding Exercises - Excursion and Valuable Indications for Therapy
Sarah Arnold
 
Nystagmus01
Nystagmus01Nystagmus01
Nystagmus01
Ram Gopal
 

What's hot (18)

Central nervous system vidhya
Central nervous system vidhyaCentral nervous system vidhya
Central nervous system vidhya
 
Issues in brainmapping...Neonatal EEG
Issues in brainmapping...Neonatal EEGIssues in brainmapping...Neonatal EEG
Issues in brainmapping...Neonatal EEG
 
Radiological pathology of brain developmental disorders
Radiological pathology of brain developmental disordersRadiological pathology of brain developmental disorders
Radiological pathology of brain developmental disorders
 
Neural tissue mobilization (Assessment)
Neural tissue mobilization (Assessment)Neural tissue mobilization (Assessment)
Neural tissue mobilization (Assessment)
 
Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...
Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...
Jorge Alberto Costa e Silva-Psiquiatría: situación actual y perspectivas de f...
 
hypotonia by Dr tadele teshome
hypotonia  by Dr tadele teshomehypotonia  by Dr tadele teshome
hypotonia by Dr tadele teshome
 
Module 4 cranial nerve
Module 4 cranial nerveModule 4 cranial nerve
Module 4 cranial nerve
 
Principles of peripheral nerve repair
Principles of peripheral nerve repairPrinciples of peripheral nerve repair
Principles of peripheral nerve repair
 
Neural tissue mobilization Upper Limb Assessment
Neural tissue mobilization Upper Limb AssessmentNeural tissue mobilization Upper Limb Assessment
Neural tissue mobilization Upper Limb Assessment
 
Neurological examination of vety patient.
Neurological examination of vety patient.Neurological examination of vety patient.
Neurological examination of vety patient.
 
Neurological exam lecture_notes
Neurological exam lecture_notesNeurological exam lecture_notes
Neurological exam lecture_notes
 
neurodynamic-testing-and-neural-mobilization.pdf
neurodynamic-testing-and-neural-mobilization.pdfneurodynamic-testing-and-neural-mobilization.pdf
neurodynamic-testing-and-neural-mobilization.pdf
 
Foot drop
Foot dropFoot drop
Foot drop
 
neural mobilization
neural mobilizationneural mobilization
neural mobilization
 
Upper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdf
Upper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdfUpper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdf
Upper-Limb-NEURODYNAMICS-LEVEL-3_TG.pdf
 
Neurodynamics
NeurodynamicsNeurodynamics
Neurodynamics
 
Nerve Gliding Exercises - Excursion and Valuable Indications for Therapy
Nerve Gliding Exercises - Excursion and Valuable Indications for TherapyNerve Gliding Exercises - Excursion and Valuable Indications for Therapy
Nerve Gliding Exercises - Excursion and Valuable Indications for Therapy
 
Nystagmus01
Nystagmus01Nystagmus01
Nystagmus01
 

Similar to Medicina felina semiologie féline - examen nerveux

Anatomy and physiology of the nervous system
Anatomy and physiology of the nervous systemAnatomy and physiology of the nervous system
Anatomy and physiology of the nervous system
Shaimaa Ibrahim
 
Neurology
NeurologyNeurology
Cranial Nerve Assessment
Cranial Nerve AssessmentCranial Nerve Assessment
Cranial Nerve Assessment
TeMz Gordonas
 
Human reflexes
Human reflexesHuman reflexes
Human reflexes
med_students0
 
nervous system part 1 Dr Ahmed H Ahmed.pdf
nervous system part 1 Dr Ahmed H Ahmed.pdfnervous system part 1 Dr Ahmed H Ahmed.pdf
nervous system part 1 Dr Ahmed H Ahmed.pdf
Salahaddin University
 
Oculomotor Nerve
Oculomotor NerveOculomotor Nerve
Oculomotor Nerve
Sinchana SK
 
Neurological Handouts
Neurological HandoutsNeurological Handouts
Neurological Handouts
jben501
 
Coma and altered consciousness
Coma  and altered consciousnessComa  and altered consciousness
Coma and altered consciousness
Saher Farghly
 
Oculomotor Nerve
Oculomotor NerveOculomotor Nerve
Oculomotor Nerve
Green Green
 
Occulomotor nerves
Occulomotor nervesOcculomotor nerves
Occulomotor nerves
cooravi
 
CEREBELLUM.pptx
CEREBELLUM.pptxCEREBELLUM.pptx
CEREBELLUM.pptx
KavithaAnandhan2
 
Nervous system
Nervous systemNervous system
Nervous system
ariannarecio
 
Nervous system
Nervous systemNervous system
Nervous system
ariannarecio
 
Myelopathy - spinal cord lesions.pptx
Myelopathy - spinal cord lesions.pptxMyelopathy - spinal cord lesions.pptx
Myelopathy - spinal cord lesions.pptx
Jwan AlSofi
 
Supranuclear control of gaze
Supranuclear control of gazeSupranuclear control of gaze
Supranuclear control of gaze
Dr. Arghya Deb
 
Cerebral palsy by padma
Cerebral palsy by padmaCerebral palsy by padma
Cerebral palsy by padma
psingh_94
 
dizziness, vertigo, balance, migraine
dizziness, vertigo, balance, migrainedizziness, vertigo, balance, migraine
dizziness, vertigo, balance, migraine
Kostiantyn
 
ppt Neurological examination for extension stude(0).pptx
ppt Neurological examination  for extension stude(0).pptxppt Neurological examination  for extension stude(0).pptx
ppt Neurological examination for extension stude(0).pptx
MohammedAbdela7
 
Neuroophthalmology
NeuroophthalmologyNeuroophthalmology
Neuroophthalmology
Neurology Zagazig
 
Seizure
SeizureSeizure
Seizure
RijoLijo
 

Similar to Medicina felina semiologie féline - examen nerveux (20)

Anatomy and physiology of the nervous system
Anatomy and physiology of the nervous systemAnatomy and physiology of the nervous system
Anatomy and physiology of the nervous system
 
Neurology
NeurologyNeurology
Neurology
 
Cranial Nerve Assessment
Cranial Nerve AssessmentCranial Nerve Assessment
Cranial Nerve Assessment
 
Human reflexes
Human reflexesHuman reflexes
Human reflexes
 
nervous system part 1 Dr Ahmed H Ahmed.pdf
nervous system part 1 Dr Ahmed H Ahmed.pdfnervous system part 1 Dr Ahmed H Ahmed.pdf
nervous system part 1 Dr Ahmed H Ahmed.pdf
 
Oculomotor Nerve
Oculomotor NerveOculomotor Nerve
Oculomotor Nerve
 
Neurological Handouts
Neurological HandoutsNeurological Handouts
Neurological Handouts
 
Coma and altered consciousness
Coma  and altered consciousnessComa  and altered consciousness
Coma and altered consciousness
 
Oculomotor Nerve
Oculomotor NerveOculomotor Nerve
Oculomotor Nerve
 
Occulomotor nerves
Occulomotor nervesOcculomotor nerves
Occulomotor nerves
 
CEREBELLUM.pptx
CEREBELLUM.pptxCEREBELLUM.pptx
CEREBELLUM.pptx
 
Nervous system
Nervous systemNervous system
Nervous system
 
Nervous system
Nervous systemNervous system
Nervous system
 
Myelopathy - spinal cord lesions.pptx
Myelopathy - spinal cord lesions.pptxMyelopathy - spinal cord lesions.pptx
Myelopathy - spinal cord lesions.pptx
 
Supranuclear control of gaze
Supranuclear control of gazeSupranuclear control of gaze
Supranuclear control of gaze
 
Cerebral palsy by padma
Cerebral palsy by padmaCerebral palsy by padma
Cerebral palsy by padma
 
dizziness, vertigo, balance, migraine
dizziness, vertigo, balance, migrainedizziness, vertigo, balance, migraine
dizziness, vertigo, balance, migraine
 
ppt Neurological examination for extension stude(0).pptx
ppt Neurological examination  for extension stude(0).pptxppt Neurological examination  for extension stude(0).pptx
ppt Neurological examination for extension stude(0).pptx
 
Neuroophthalmology
NeuroophthalmologyNeuroophthalmology
Neuroophthalmology
 
Seizure
SeizureSeizure
Seizure
 

More from Guillaume Michigan

Fitoterapia Veterinaria
Fitoterapia VeterinariaFitoterapia Veterinaria
Fitoterapia Veterinaria
Guillaume Michigan
 
Evening visualization check list
Evening visualization check listEvening visualization check list
Evening visualization check list
Guillaume Michigan
 
Neonatologia equina - Neonato equino
Neonatologia equina - Neonato equino Neonatologia equina - Neonato equino
Neonatologia equina - Neonato equino
Guillaume Michigan
 
Anatomia de la Rodilla y tarso del Canino
Anatomia de la Rodilla y tarso del CaninoAnatomia de la Rodilla y tarso del Canino
Anatomia de la Rodilla y tarso del Canino
Guillaume Michigan
 
ECOGRAFIA RODILLA DEL PERRO
ECOGRAFIA RODILLA DEL PERROECOGRAFIA RODILLA DEL PERRO
ECOGRAFIA RODILLA DEL PERRO
Guillaume Michigan
 
ECOGRAFIA DE LA RODILLA DEL PERRO
ECOGRAFIA DE LA RODILLA DEL PERROECOGRAFIA DE LA RODILLA DEL PERRO
ECOGRAFIA DE LA RODILLA DEL PERRO
Guillaume Michigan
 
Ecografia del aparato genital de la perra - Gestacion
Ecografia del aparato genital de la perra - GestacionEcografia del aparato genital de la perra - Gestacion
Ecografia del aparato genital de la perra - Gestacion
Guillaume Michigan
 
Programme integral
Programme integral   Programme integral
Programme integral
Guillaume Michigan
 
Ecografia hepatica del perro
Ecografia hepatica del perroEcografia hepatica del perro
Ecografia hepatica del perro
Guillaume Michigan
 
Enfermedades de las vías respiratorias altas en los felinos
Enfermedades de las vías respiratorias altas en los felinosEnfermedades de las vías respiratorias altas en los felinos
Enfermedades de las vías respiratorias altas en los felinos
Guillaume Michigan
 
Medicina felina digestivo
Medicina felina   digestivoMedicina felina   digestivo
Medicina felina digestivo
Guillaume Michigan
 
Medicina felina ophtalmologie - abces orbtaire felin
Medicina felina   ophtalmologie - abces orbtaire felinMedicina felina   ophtalmologie - abces orbtaire felin
Medicina felina ophtalmologie - abces orbtaire felin
Guillaume Michigan
 
Medicina felina bordetella bronchiseptica infection in cats. abcd guideline...
Medicina felina   bordetella bronchiseptica infection in cats. abcd guideline...Medicina felina   bordetella bronchiseptica infection in cats. abcd guideline...
Medicina felina bordetella bronchiseptica infection in cats. abcd guideline...
Guillaume Michigan
 
Medicina felina kitten behavior (1)
Medicina felina   kitten behavior (1)Medicina felina   kitten behavior (1)
Medicina felina kitten behavior (1)
Guillaume Michigan
 
Medicina felina complexe gingivo-stomatique chronique félin
Medicina felina    complexe gingivo-stomatique chronique félinMedicina felina    complexe gingivo-stomatique chronique félin
Medicina felina complexe gingivo-stomatique chronique félin
Guillaume Michigan
 
Trichomonas fœtus
Trichomonas fœtusTrichomonas fœtus
Trichomonas fœtus
Guillaume Michigan
 
Medicina felina convulsion seizures in cats
Medicina felina   convulsion seizures in catsMedicina felina   convulsion seizures in cats
Medicina felina convulsion seizures in cats
Guillaume Michigan
 
Medicina felina nefrologia - uremia aguda felina
Medicina felina   nefrologia - uremia aguda felinaMedicina felina   nefrologia - uremia aguda felina
Medicina felina nefrologia - uremia aguda felina
Guillaume Michigan
 
Medicina felina feline-soft-tissue-surgery-part-2-pdf
Medicina felina   feline-soft-tissue-surgery-part-2-pdfMedicina felina   feline-soft-tissue-surgery-part-2-pdf
Medicina felina feline-soft-tissue-surgery-part-2-pdf
Guillaume Michigan
 
Medicina felina consequences of cholestasis in cats - procedings
Medicina felina   consequences of cholestasis in cats - procedingsMedicina felina   consequences of cholestasis in cats - procedings
Medicina felina consequences of cholestasis in cats - procedings
Guillaume Michigan
 

More from Guillaume Michigan (20)

Fitoterapia Veterinaria
Fitoterapia VeterinariaFitoterapia Veterinaria
Fitoterapia Veterinaria
 
Evening visualization check list
Evening visualization check listEvening visualization check list
Evening visualization check list
 
Neonatologia equina - Neonato equino
Neonatologia equina - Neonato equino Neonatologia equina - Neonato equino
Neonatologia equina - Neonato equino
 
Anatomia de la Rodilla y tarso del Canino
Anatomia de la Rodilla y tarso del CaninoAnatomia de la Rodilla y tarso del Canino
Anatomia de la Rodilla y tarso del Canino
 
ECOGRAFIA RODILLA DEL PERRO
ECOGRAFIA RODILLA DEL PERROECOGRAFIA RODILLA DEL PERRO
ECOGRAFIA RODILLA DEL PERRO
 
ECOGRAFIA DE LA RODILLA DEL PERRO
ECOGRAFIA DE LA RODILLA DEL PERROECOGRAFIA DE LA RODILLA DEL PERRO
ECOGRAFIA DE LA RODILLA DEL PERRO
 
Ecografia del aparato genital de la perra - Gestacion
Ecografia del aparato genital de la perra - GestacionEcografia del aparato genital de la perra - Gestacion
Ecografia del aparato genital de la perra - Gestacion
 
Programme integral
Programme integral   Programme integral
Programme integral
 
Ecografia hepatica del perro
Ecografia hepatica del perroEcografia hepatica del perro
Ecografia hepatica del perro
 
Enfermedades de las vías respiratorias altas en los felinos
Enfermedades de las vías respiratorias altas en los felinosEnfermedades de las vías respiratorias altas en los felinos
Enfermedades de las vías respiratorias altas en los felinos
 
Medicina felina digestivo
Medicina felina   digestivoMedicina felina   digestivo
Medicina felina digestivo
 
Medicina felina ophtalmologie - abces orbtaire felin
Medicina felina   ophtalmologie - abces orbtaire felinMedicina felina   ophtalmologie - abces orbtaire felin
Medicina felina ophtalmologie - abces orbtaire felin
 
Medicina felina bordetella bronchiseptica infection in cats. abcd guideline...
Medicina felina   bordetella bronchiseptica infection in cats. abcd guideline...Medicina felina   bordetella bronchiseptica infection in cats. abcd guideline...
Medicina felina bordetella bronchiseptica infection in cats. abcd guideline...
 
Medicina felina kitten behavior (1)
Medicina felina   kitten behavior (1)Medicina felina   kitten behavior (1)
Medicina felina kitten behavior (1)
 
Medicina felina complexe gingivo-stomatique chronique félin
Medicina felina    complexe gingivo-stomatique chronique félinMedicina felina    complexe gingivo-stomatique chronique félin
Medicina felina complexe gingivo-stomatique chronique félin
 
Trichomonas fœtus
Trichomonas fœtusTrichomonas fœtus
Trichomonas fœtus
 
Medicina felina convulsion seizures in cats
Medicina felina   convulsion seizures in catsMedicina felina   convulsion seizures in cats
Medicina felina convulsion seizures in cats
 
Medicina felina nefrologia - uremia aguda felina
Medicina felina   nefrologia - uremia aguda felinaMedicina felina   nefrologia - uremia aguda felina
Medicina felina nefrologia - uremia aguda felina
 
Medicina felina feline-soft-tissue-surgery-part-2-pdf
Medicina felina   feline-soft-tissue-surgery-part-2-pdfMedicina felina   feline-soft-tissue-surgery-part-2-pdf
Medicina felina feline-soft-tissue-surgery-part-2-pdf
 
Medicina felina consequences of cholestasis in cats - procedings
Medicina felina   consequences of cholestasis in cats - procedingsMedicina felina   consequences of cholestasis in cats - procedings
Medicina felina consequences of cholestasis in cats - procedings
 

Recently uploaded

Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)
Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)
Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)
MuskanShingari
 
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...
Université de Montréal
 
acne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticals
acne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticalsacne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticals
acne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticals
MuskanShingari
 
Pharmacology of 5-hydroxytryptamine and Antagonist
Pharmacology of 5-hydroxytryptamine and AntagonistPharmacology of 5-hydroxytryptamine and Antagonist
Pharmacology of 5-hydroxytryptamine and Antagonist
Dr. Nikhilkumar Sakle
 
Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...
Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...
Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...
ayushrajshrivastava7
 
Microbiology & Parasitology Exercises Parts of the Microscope
Microbiology & Parasitology Exercises Parts of the MicroscopeMicrobiology & Parasitology Exercises Parts of the Microscope
Microbiology & Parasitology Exercises Parts of the Microscope
ThaShee2
 
Public Health Lecture 4 Social Sciences and Public Health
Public Health Lecture 4 Social Sciences and Public HealthPublic Health Lecture 4 Social Sciences and Public Health
Public Health Lecture 4 Social Sciences and Public Health
phuakl
 
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7
shruti jagirdar
 
June 2024 Oncology Cartoons By Dr Kanhu Charan Patro
June 2024 Oncology Cartoons By Dr Kanhu Charan PatroJune 2024 Oncology Cartoons By Dr Kanhu Charan Patro
June 2024 Oncology Cartoons By Dr Kanhu Charan Patro
Kanhu Charan
 
What is Obesity? How to overcome Obesity?
What is Obesity? How to overcome Obesity?What is Obesity? How to overcome Obesity?
What is Obesity? How to overcome Obesity?
Healthmedsrx.com
 
Giloy in Ayurveda - Classical Categorization and Synonyms
Giloy in Ayurveda - Classical Categorization and SynonymsGiloy in Ayurveda - Classical Categorization and Synonyms
Giloy in Ayurveda - Classical Categorization and Synonyms
Planet Ayurveda
 
Call Girls Lucknow 9024918724 Vip Call Girls Lucknow
Call Girls Lucknow 9024918724 Vip Call Girls LucknowCall Girls Lucknow 9024918724 Vip Call Girls Lucknow
Call Girls Lucknow 9024918724 Vip Call Girls Lucknow
nandinirastogi03
 
Nano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory projectNano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory project
SIVAVINAYAKPK
 
Nutritional deficiency disorder in Child
Nutritional deficiency disorder in ChildNutritional deficiency disorder in Child
Nutritional deficiency disorder in Child
Bhavyakelawadiya
 
Pollen and Fungal allergy: aeroallergy.pdf
Pollen and Fungal allergy: aeroallergy.pdfPollen and Fungal allergy: aeroallergy.pdf
Pollen and Fungal allergy: aeroallergy.pdf
Chulalongkorn Allergy and Clinical Immunology Research Group
 
Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...
Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...
Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...
FFragrant
 
Cervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptxCervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptx
LEFLOT Jean-Louis
 
13. PROM premature rupture of membranes
13.  PROM premature rupture of membranes13.  PROM premature rupture of membranes
13. PROM premature rupture of membranes
TigistuMelak
 
KENT'S REPERTORY by dr niranjan mohanty.pptx
KENT'S REPERTORY by dr niranjan mohanty.pptxKENT'S REPERTORY by dr niranjan mohanty.pptx
KENT'S REPERTORY by dr niranjan mohanty.pptx
SravsPandu1
 
Hemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.Gawad
Hemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.GawadHemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.Gawad
Hemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.Gawad
NephroTube - Dr.Gawad
 

Recently uploaded (20)

Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)
Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)
Computer in pharmaceutical research and development-Mpharm(Pharmaceutics)
 
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...
“Psychiatry and the Humanities”: An Innovative Course at the University of Mo...
 
acne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticals
acne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticalsacne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticals
acne vulgaris -Mpharm (2nd semester) Cosmetics and cosmeceuticals
 
Pharmacology of 5-hydroxytryptamine and Antagonist
Pharmacology of 5-hydroxytryptamine and AntagonistPharmacology of 5-hydroxytryptamine and Antagonist
Pharmacology of 5-hydroxytryptamine and Antagonist
 
Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...
Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...
Full Handwritten notes of RA by Ayush Kumar M pharm - Al ameen college of pha...
 
Microbiology & Parasitology Exercises Parts of the Microscope
Microbiology & Parasitology Exercises Parts of the MicroscopeMicrobiology & Parasitology Exercises Parts of the Microscope
Microbiology & Parasitology Exercises Parts of the Microscope
 
Public Health Lecture 4 Social Sciences and Public Health
Public Health Lecture 4 Social Sciences and Public HealthPublic Health Lecture 4 Social Sciences and Public Health
Public Health Lecture 4 Social Sciences and Public Health
 
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7
STUDIES IN SUPPORT OF SPECIAL POPULATIONS: GERIATRICS E7
 
June 2024 Oncology Cartoons By Dr Kanhu Charan Patro
June 2024 Oncology Cartoons By Dr Kanhu Charan PatroJune 2024 Oncology Cartoons By Dr Kanhu Charan Patro
June 2024 Oncology Cartoons By Dr Kanhu Charan Patro
 
What is Obesity? How to overcome Obesity?
What is Obesity? How to overcome Obesity?What is Obesity? How to overcome Obesity?
What is Obesity? How to overcome Obesity?
 
Giloy in Ayurveda - Classical Categorization and Synonyms
Giloy in Ayurveda - Classical Categorization and SynonymsGiloy in Ayurveda - Classical Categorization and Synonyms
Giloy in Ayurveda - Classical Categorization and Synonyms
 
Call Girls Lucknow 9024918724 Vip Call Girls Lucknow
Call Girls Lucknow 9024918724 Vip Call Girls LucknowCall Girls Lucknow 9024918724 Vip Call Girls Lucknow
Call Girls Lucknow 9024918724 Vip Call Girls Lucknow
 
Nano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory projectNano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory project
 
Nutritional deficiency disorder in Child
Nutritional deficiency disorder in ChildNutritional deficiency disorder in Child
Nutritional deficiency disorder in Child
 
Pollen and Fungal allergy: aeroallergy.pdf
Pollen and Fungal allergy: aeroallergy.pdfPollen and Fungal allergy: aeroallergy.pdf
Pollen and Fungal allergy: aeroallergy.pdf
 
Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...
Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...
Demystifying Fallopian Tube Blockage- Grading the Differences and Implication...
 
Cervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptxCervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptx
 
13. PROM premature rupture of membranes
13.  PROM premature rupture of membranes13.  PROM premature rupture of membranes
13. PROM premature rupture of membranes
 
KENT'S REPERTORY by dr niranjan mohanty.pptx
KENT'S REPERTORY by dr niranjan mohanty.pptxKENT'S REPERTORY by dr niranjan mohanty.pptx
KENT'S REPERTORY by dr niranjan mohanty.pptx
 
Hemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.Gawad
Hemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.GawadHemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.Gawad
Hemodialysis: Chapter 6, Hemodialysis Adequacy and Dose - Dr.Gawad
 

Medicina felina semiologie féline - examen nerveux

  • 1. HOW TO PERFORM A NEUROLOGICAL EXAMINATION NEUROLOGY ON A CAT AND LOCALIZE THE LESION Simon Platt, BVM&S, MRCVS, DACVIM (Neurology), DECVN The nervous system plays a role in nearly all body processes. Disease syndromes may affect the central nervous system (CNS), which includes the brain and spinal cord, and the peripheral nervous system, which includes cranial nerves, spinal cord nerve roots, spinal nerves, peripheral nerve branches, and the neuromuscular junction. Suspicion of neurological dysfunction arises from the history and physical examination. The signalment, presenting chief complaint, time course of clinical signs, and history may suggest the type of disease process or species-specific disorder. A complete neurologic examination is necessary to localize the anatomic distribution, to determine the severity of the disease process, and to assess the prognosis for patient recovery. A neurological examination is easily integrated into a routine physical examination. The objectives of the neurological examination are to confirm if there is a neurological abnormality and to specifically localize the abnormality within the nervous system. In conjunction with the history, signalment, presenting complaint, and the physical examination, the neurological lesion localization is a piece of a jigsaw essential to creating a list of differential diagnoses for the disease. However, caution must be used as some manipulations necessary for the neurological examination could exacerbate problems such as spinal cord disease. Observation Observation of the dog or cat is essential as it allows evaluation of the mentation, posture, attitude, and gait. Changes in mentation (level and content of consciousness) are revealed by a history of personality change, change in awareness of surroundings, and inappropriate behavioural responses. Consciousness is a function of the brainstem (responsible for arousal) and the cerebral cortex (responsible for content and regulation). The evaluation of the state of consciousness can classify the patient as depressed, demented or obtunded, delirious, stuporous, and comatose. Palpation The musculoskeletal system should be palpated for asymmetry, masses, tenderness, and tone. A mass, tenderness, or contour change requires further investigation. The vertebral column should be palpated for deviations and pain being cautious not to apply too much pressure if suspicious of an instability. Unilateral muscle mass loss or atrophy may indicate disuse if it is chronic or a neurogenic loss if it is acute (within seven to 10 days). Cranial Nerves Cranial nerves have specific functions and evaluation of these functions can help to precisely locate a neurological lesion due to their well-documented anatomy. The general functions and specific tests are summarized in Table 1. Simplistically, cranial nerve dysfunction may indicate a central nervous system (CNS) lesion (brainstem disease) or a peripheral lesion (affecting the cranial nerves after they have exited the brainstem and course through the skull). Evaluation of the cranial nerves should follow observation and palpation, with particular attention paid to normal functions of eye movement, head movement, blinking, jaw and tongue movement, and general symmetry of the head. Initially an ophthalmic exam should be performed, which will assist with the evaluation of the optic (CN II), oculomotor (CN III), trochelar (CN IV), and abducens (CN VI) nerves. The following tests are essential to the evaluation of cranial nerve function: The Menace Response 1. How to perform—obscure the vision in one eye and make slow threatening hand gesture toward the other eye. 2. How to interpret—this is a learned response, not a reflex, to a perceived threat, which evaluates CNs II and VII (responsible for innervation of the orbicularis oculi muscle which closes the eyelids), as well as the central visual pathways and the cerebellum. Normal function is demonstrated by a blink or retraction of the globe in response to the threat. To localize the lesion, other cranial nerve tests would be required.
  • 2. The Pupillary Light Reflex 1. How to perform—shine a bright light in each eye to evaluate the response of the pupil. 2. How to interpret—this is a reflex. Light is sensed by CN II; parasympathetic fibers of CN III cause contraction of the iris muscle with direct and indirect simulation. The pupil is also innervated by sympathetic fibres responsible for dilation, which have their origin in the thalamus and send fibres down the cervical spinal cord to the T1-T3 spinal nerve roots before they ascend up the neck and through the middle ear. A resting inequality in pupil size is termed anioscoria; to determine which pupil is abnormal, the animal should be evaluated in the light and dark. In the dark, a sympathetic lesion will mean the affected pupil will not be able to fully dilate. In the light, a parasympathetic lesion will mean the affected pupil will not be able to fully constrict. Animals with sympathetic lesions will often demonstrate miosis in accompaniment to third eyelid protrusion and enophthalmus, a condition called Horner’s syndrome. Evaluation of Strabismus 1. How to perform—observe the animal’s head in a normal position for a deviation of one or both globes in the orbit(s). 2. How to interpret—cranial nerves III, IV, and VI aid vision by maintaining the globe in a central position. Deviation of the globe from its central axis indicates dysfunction in one or more of these nerves: ventrolateral—CN III, dorsolateral—CN IV, and medial—CN VI. The Palpebral Reflex 1. How to perform—touch the medial canthus of the normal eyelid and watch response. 2. How to interpret—the normal eyelid should close. Cranial nerve V (trigeminal nerve) is responsible for facial sensation, whereas the motor response to facial sensory stimulation is generally provided by the facial nerve (CN VII). Facial paresis presents as a drooping of the facial muscles, most notably the lips and the eyelids. It may also be detected as a reduction or absence in the blink response. Evaluation of Jaw Tone 1. How to perform—observe patient for a dropped lower jaw and/or an inability to eat. Assess the strength of the jaw safely by manually opening the mouth and evaluating the resistance to opening. 2. How to interpret—the mandibular branch of CN V provides motor function to the jaw. A dropped lower jaw or the inability to chew can indicate damage to CN V. The Oculocephalic Reflex/Physiological Nystagmus 1. How to perform—move the head from side to side in a horizontal plane and observe the resulting movement of the eyes. 2. How to interpret—in normal animals, a physiological nystagmus will be induced, with the fast phase in the direction of head movement. This reflex tests the integrity of CN VIII (vestibulocochlear nerve), which is the sensory arm of this reflex, and CNs III, IV, and VI, which are responsible for the motor movement of the eyes. Clinical signs of peripheral vestibular disease are manifest after damage to the inner ear or vestibular branch of CN VIII, which effectively gives unbalanced input to the intact central vestibular system. In the absence of head motion, spontaneous horizontal nystagmus is consistent with CN VIII damage, with the fast component away from the side of the lesion. Unilateral peripheral disease may cause a head tilt and circling to the side of the lesion. Postural Reactions The postural reactions are complex, requiring intact sensory and motor pathways throughout the nervous system as well as unimpaired processing and integration in the brain. The complexity of the postural reactions allows detection of minor deficits in any key component of the pathway. Postural deficits are seen caudal to or at the level of the lesion. Additional testing must be performed to use the postural deficit to help localize the lesion within the pathway of the deficit. 1. How to perform—a leg is placed in an abnormal position and a correcting response by the animal is observed. Knuckling the toes over whilst supporting the body can be done to evaluate how long it takes for the animal to correct. Alternatively, a piece of paper may be placed under each foot and slowly
  • 3. moved sideways, to see if the animal returns its foot to the standing position. Other postural reactions include wheelbarrowing, hopping, hemistanding, and extensor postural thrust. 2. How to interpret—conscious proprioception is the patient’s awareness of limb position and movement without visual information. When the knuckling test is performed, an abnormality is indicated by a delay or absence of the response. The sensory branch of proprioception is carried from the skin, muscle, and joints of the leg through the spinal cord and brainstem to the sensory motor cortex, where the brain responds by sending messages back to the lower motor neuron for motor function, resulting in a rapid correcting foot placement. Ascending sensory pathways are located in the outermost regions of the spinal cord and are very sensitive to compression. With minor spinal cord injury, proprioceptive deficits may be present because of disrupted sensory pathways, while motor function persists because the deeper motor tracts are unaffected. Both visual and tactile placing reactions require an intact motor cortex and intact motor pathways to the involved limb. A cortical lesion may produce deficits in the contralateral limb, whereas lower lesion produces deficits in the ipsilateral limb. Spinal Reflexes It is rare to have any reflex abnormalities if the animal has no evidence of gait abnormality, muscle mass loss, or conscious proprioceptive deficits. In these cases, a complete reflex examination is unlikely to be helpful. Completion of a reflex requires an intact sensory nerve that provides transmission to the spinal cord and an intact motor nerve that elicits function from the innervated muscle. The reflex arc itself does not involve the brain or the remainder of the spinal cord. Lesions in the motor arm of the reflex arc, termed lower motor neuron (LMN), may cause a decreased or absent reflex (hyporeflexia or areflexia). An exaggerated response (hyperreflexia) results from an interruption in proximal motor pathways that modulate the reflex, termed upper motor neuron (UMN); however, stress or anxiety may cause an apparent increased reflex response, so it should not be considered too important without other evidence of neurological disease. Lower motor neuron signs indicate damage to one or more components of the reflex arc. Upper motor neuron signs indicate damage anywhere between the reflex arc and the brain (Table 2). The most reliable reflex is the flexor withdrawal in the thoracic and pelvic limbs. The other reflexes can appear to be present in small dogs just because the limbs will move when struck with a reflex hammer irrespective of reflex function. The Anal Sphincter Reflex 1. How to perform—pinch the anal sphincter with haemostats and watch for a wink-like contraction of the external sphincter muscles and tail flexion. 2. How to interpret—this reflex reveals information regarding the pudendal nerve and caudal segments of the spinal cord. A flaccid, unresponsive anus indicates LMN damage to the pudendal nerve or its spinal roots. A hypertonic, hyperresponsive anal sphincter indicates UMN damage at any point cranial to the pudendal nerve. The Pedal Flexor Reflex 1. How to perform—apply a pinch stimulus to each foot and evaluate the response of the ipsilateral and contralateral limb. 2. How to interpret—this is a withdrawal reflex in which stimulation of sensory receptors in the toes elicits contraction of flexor muscle groups in the leg. Presence of a withdrawal reflex requires an intact sciatic nerve (sensory and motor) and an intact spinal segment at the lumbosacral plexus, but does not require transmission along the spinal cord to the brain. Absence of the withdrawal reflex in the pelvic limb denotes extensive lower motor neuron damage involving the lumbosacral spinal cord segments (L6-S2) as well as the nerve roots and the lumbosacral plexus; in the thoracic limb it denotes damage to the cervical spinal cord segments (C6-T2), the spinal nerve roots and the brachial plexus. The Patella Reflex 1. How to perform—a tap stimulus should be applied to the straight patella tendon and the response of the limb should be evaluated. Reflex hammer size must be adapted to patient size for improved accuracy. 2. How to interpret—this is a myotactic (stretch) reflex that effectively stretches the quadriceps muscle. This stretch stimulates the femoral nerve (L4-L5), which generates muscular contraction to extend the stifle. Upper motor neuron lesions cause hyperreflexia and should be accompanied by weakness and poor weight bearing. Disease in the L4-L5 spinal cord segments or nerves causes hyporeflexia. Cutaneous Sensation and Pain
  • 4. Cutaneous sensation testing provides information regarding the location and severity of a spinal cord or peripheral nerve lesion. Evaluation of nociception (deep pain perception) is reserved for those animals showing evidence of spinal cord disease based on abnormalities in gait, proprioception, and spinal reflexes. Lack of deep pain sensation is a poor prognostic factor as it indicates severe nervous system damage. Nociception requires cerebral perception of painful or injurious stimuli. It is important to remember that a withdrawal reflex is not an indicator of pain perception and may be elicited in an animal whose spinal cord has been transected cranial to the segment responsible for that reflex arc. Hyperpathia is the sensation of pain produced by an innocuous stimulus such as palpating the vertebrae. All of the cervical and thoracolumbar vertebra should all be palpated to detect focal points of hyperpathia which may help localize the neurological lesion and will help with the differential diagnosis
  • 5. Table 1. Cranial Nerves: Function and Applicable Tests Cranial Nerve Nerve Function Applicable Tests I Olfactory Smell i. Blindfold the animal and monitor behavioural response to food placed near nose; loss of smell usually due to nasal disease rather than neurological disease II Optic Vision i. Menace response ii. Pupillary light reflex iii. Obstacle course iv. Dropping cotton wool balls in front of each eye III Oculomotor Extrinsic and intrinsic ocular muscles /upper eyelid muscle i. Eyeball position ii. Pupil size (mydriatic in disease) iii. Physiological nystagmus iv. Pupillary light reflex IV Trochlear Extrinsic ocular muscles i. Eyeball position V Trigeminal Facial sensation /jaw movement i. Palpebral reflex ii. Jaw & masticatory muscle palpation VI Abducens Extrinsic ocular muscles i. Eyeball position ii. Physiological nystagmus VII Facial Muscles of facial expression / parasympathetic supply to lacrimal glands i. Palpebral response ii. Evaluation of facial symmetry iii. Shirmer tear test VIII Vestibulocochlear Hearing and balance i. Oculocephalic reflexes ii. Assessment for head tilt IX Glossopharyngeal Muscles of pharynx & larynx i. Gag reflex X Vagus Muscles of larynx & pharynx i. Gag reflex XI Accessory Superficial neck muscles i. None applicable XII Hypoglossal Muscles of tongue i. Tongue grab/inspection Table 2. Clinical signs associated with upper motor neuron (UMN) and lower motor neuron (LMN) disease Clinical Function UMN disease LMN disease Motor function Paresis or paralysis Paresis or paralysis Muscle tone Normal to increased Often reduced Spinal reflexes Normal to decreased Decreased to absent Muscle mass Normal to decreased (disuse atrophy) Dramatically decreased after five to seven days (neurogenic atrophy) Conscious proprioception Often reduced to absent Often reduced to absent