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What does loss of proprioception tell you clinically?
Doesn't localize the lesion, but a sensitive indication of a neurological problem (anywhere along the proprioceptive pathway: peripheral nerves, spinal cord, brain stem, cerebrum, or cerebellum)
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Paralysis
Complete loss of motor activity
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Paresis
Weakness, partial loss of voluntary motor activity
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What are the suffixes -paresis and -plegia used to describe?
Paresis and paralysis, respectively
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Differentiate flaccid and spastic paresis or paralysis.
- Flaccid: decreased or no tone in muscles
- Spastic: increased tone/hypertonicity
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Ataxia
Lack of coordinated movements with or without spasticity or paresis
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What can cause ataxia?
Lesions of the entire NS may cause ataxia. Although not specific, it shows up frequently and is indicative of a NS problem.
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Define intention tremor and what it indicates.
- A tremor (sma,, rapid, alternating movements at rest) that becomes worse with initiation of a movement and disappears at rest
- Indicates cerebellar disease
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Nystagmus
Involuntary movement of the eyes in either a rotatory, vertical, or horizontal direction
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How does nystagmus at rest appear and what does it indicate?
- Eyes move to the side of lesion and snap back
- Abnormality, usually indicates vestibular dysfunction
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Dysmetria and what does it indicate?
- Improper measuring of distance in muscular activity, too short or too long (i.e. goose stepping)
- Indicates cerebellar disease
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How do you screen for neurological problems?
- Mental attitude/consciousness, behavior, seizures
- Stance and head position
- Gait and strength
- Proprioceptive positioning
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Why is mental attitude/consciousness, behavior, seizures observed in a neuroscreening test?
Screen for cerebrum and brain stem problems.
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What does observation of stance and head position of a neuroscreening test check?
Cerebellar problem
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What abnormal stance and head position indicate neurological problems (cerebellum/vestibular system)?
Head tilt, wide based stance; head tremor/bobbing
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What does gait and strength observation evaluate?
Entire NS
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What is gait checked for during a neurological screening test?
Peoprioceptive deficits, paresis circling, ataxia and dysmetria, scuffing, knuckling or atrophy
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What does abnormalities in gait indicate in a neurological screening?
NS problem (cerebrum, cerebellum, brain stem, spinal cord, peripheral nerves, or vestibular lesions
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Do gait abnormalities localize a neurological lesion?
No, just a neurological problem that can be anywhere: cerebrum, cerebellum, brain stem, spinal cord, peripheral nerves, or vestibular system
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How is strength tested during a neurological exam?
Push down on the standing animal
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What does weakness indicate during a neuorlogical screening?
Nervous problem somewhere other than the cerebellum or peripheral vestibular system (cerebrum, brain stem or spinal cord injuries, peripheral nerves)
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What is the only part of the nervous system that will not result in weakness?
Cerebellum (& peripheral vestibular system)
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What is the most common postural reaction used to screen for neurological problems?
Proprioceptive positioning (knuckling)
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What is a neuroscreening test to indicate there is a neurological problem but doesn't localize where the problem is?
Proprioceptive positioning (knuckling), postural reaction (also gait and strength observation)
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For what does proprioceptive positioning test?
Conscious perception of the location of the limbs
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What does loss of proprioception tell you clincally?
Doesn't localize the lesion, but is a sensitive indication of a neurological problem (anywhere along the proprioceptive pathway: peripheral nerves, spinal cord, brain stem, cerebrum, or cerebellum)
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What is done once screening indicates a neurological problem?
Other procedures done to localize the lesion to a specific part of the nervous system
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What is a CSF tap and where is it done?
Removal of cerebrospinal fluid from the subarachnoid space in the cisterna magna or lumbar cistern
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What is epidural anesthesia, where is it commonly given?
Anesthetize the spinal nerves in the area, through the lumbosacral opening (L7-S1) into the epidural space
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What is the affect of UMNs damage on LMNs?
LMNs increase their activity
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To where do LMN signs localize the lesion?
Peripheral nerves, spinal cord, or segment of brain stem the LMN arises from
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Flaccid paresis or paralysis
Decreased or no tone with paresis or paralysis due to lesions of LMNs
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Spastic paresis or paralysis
Extra tone (hypertonicity) with paresis or paralysis due to lesions of UMNs
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What does pointing your thumb down in LMN damage indicate?
Everything decreased or disappears
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4 LMN disease signs (thumb down)
- Decreased or absent tone (hypo- to areflexia)
- Decreased to absent reflexes (hypo- to areflexia)
- Flaccid paralysis
- Rapid atrophy (neurogenic atrophy); usually 1 week
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4 UMN disease signs (thumb up)
- Normal to increased muscle tone
- Normal to increased reflexes (hypereflexia)
- Spastic paresis or paralysis
- Slow (disuse) atrophy
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List how the reflexes are checked for the limbs.
Withdrawal reflex
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How is a withdrawal reflex performed?
Pinch (pain) the toe; normal response = withdrawal of the limb
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How is tone evaluated?
Palpate the muscles of the limbs
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Localize the lesions: flaccid paralysis, absent reflexes and tone, and rapid atrophy to the pelvic limbs with normal thoracic limbs.
L4-S1 spinal cord lesion (area 4) (LMN signs to pelvic limbs, normal thoracic limbs)
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Localize the lesion: spastic paresis, increased reflexes and tone to the left pelvic limb and flaccid paralysis, decreased reflexes and tone to the left thoracic limb
Unilateral C6-T1 (area 2) on the left (LMN: left thoracic and UMN: left pelvic limb)
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Localize the lesion: spastic paresis, increased reflexes and increased tone to all limbs
Lesion crnial to C6 (area 1)
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Localize the lesion: spastic paresis, increased reflexes and tone to the pelvic limbs, and normal thoracic limbs
T3-L3 (area 3) (UMN: P limbs; Normal = Shiff-Sherington)
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Presenting signs of C1-5 spinal cord
All 4 limbs: UMN (thumbs up) (no LMN signs to any limb)
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Presenting sings of cervical enlargement, C6-T2
- Pelvic limbs: UMN (thumb up)
- Thoracic limbs: LMN (thumb down)
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Presenting signs of T3-L3
- Pelvic limb: UMN (thumb up)
- Thoracic limb: no effect (+/- Shiff;Sherington)
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Presenting signs of L4-S1
- Pelvic limb: LMN (thumb down)
- Thoracic limb: no effect
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What causes a coma?
Complete disconnection of the reticular activation system from the cerebral cortex, usually due to a severe brain stem lesion
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List 3 primary deficits that may be seen with lesions to the cerebrum?
- Seizures
- Behavior and mentation abnormalities
- Depression
- Abnormal posture with normal gait
- Blind with normal pupillary reflexes
- Complusive pacing, head pressing
- Proprioceptive deficits
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Unilateral cerebral lesions will cause _____ signs?
Contralateral
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How is brain stem disease characterized?
Abnormal gait and abnormal posture and cranial nerve deficits, decreased mental states, proprioception deficits and weakness
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What is the range of decreased levels of consciousness due to brainstem lesions?
Depression to coma
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What is the best evidence of brainstem lesions?
Multiple dysfunction of cranial nerves 3-12
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When should brain stem disease be suspected?
If cranial nerves abnormalities, UMN paresis, or decreased consciousness
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How does a cerebellar lesion present?
Uncoordinated without paresis (no weakness), proprioceptive deficits vestibular signs
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What do vestibular system lesions affect?
The ability to control posture in relationship to gravity and eye movements in relationship to head movements
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What are signs of vestibular disease?
Head tilt, nystagmus, asymmetric ataxia with possible circling
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What is the primary diagnostic concern with vestibular disease?
Differentiating peripheral (no pareses or depression) from central (paresis and depression) vestibular disease
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What is the first deficit to show with a neurological deficit?
Proprioceptive positioning
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What does BAR stand for?
Bright, alert, and responsive
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What does multiple dysfunction of cranial nerves indicate?
Brain stem lesion
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What would cause a dropped jaw?
Paralysis of trigeminal nerve
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Why is paralysis of the orbicuaris oculi and loss of lacrimation the most vital results of facial nerve paralysis?
Drying the eye; animals are not vain (facial paralysis)
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How is auricopalpebral nerve manipulated clinically? In what species?
Blocked to paralyze eyelids for eye procedures; large animals
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How is the facial nerve commonly injured in the horse?
Lying on a halter buckle during surgery (buccal on buckle)
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Complaint: blindness
Optic nerve (2)
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Complaint: Anisocoria (unequal sized pupils)
Sympathetic, parasympathetic (3)
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Complaint: Strabismus (uncontrolled deviation of the eye)
Oculomotor (3), trochlear (4), abducens (5)
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Complaint: Dropped jaw and head atrophy
Trigeminal nerve (5)
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Complaint: increased or decreased facial sensation
Trigeminal nerve (5)
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Complaint: facial paralysis
Facial nerve (7)
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Complaint: Deafness and/or loss of balance
Vestibulocochlear nerve (8) damage
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Complaint: Dysphagia (difficult swallowing)
Glossopharyngeal (9), vagus (10)
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Complaint: megaesophagus
Vagus (10)
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Complaint: Laryngeal paralysis
Vagus (10), recurrent laryngeal nerve
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Complaint: paralysis of the tongue
Hypoglossal (12)
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Paralysis of which nerve results in a weak tongue?
Hypoglossal nerve
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How is the facial/trigeminal reflex arc checked?
Prick the face, pulling away indicates intact trigeminal nerve, twitch of face muscles indicate intact facial nerve
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What cranial nerve problem can be seen with middle ear infections?
Paralysis of the facial nerve and resulting dry eye
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What procedure can be used to facilitate the exam of the eye? How?
Auriculopalpebral nerve block, eliminates blinking and closing of the eye (rare in dogs, common in horses)
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What are signs of damage to the recurrent laryngeal nerve?
- Laryngeal paralysis/hemiplegia: failure of the glottic cleft to open
- Seen in horses (roarers) and dogs - high pitched, whistling on inspiration and exercise intolerance occur
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Discuss the clinical significance of the accessory nerve (XI)
Little clinical significance
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Describe the pupillary light reflex and what structures it involves?
Shining a light in the eye, noting if the pupil constricts in that eye and then the other eye; checks both cranial nerves II and III (optic and oculomotor nerves)
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Describe the signs of facial nerve (VII) damage
Paralysis of the muscles of facial expression resulting in a distorted face, paralysis of the orbicularis oculi muscle and if proximal enough, the ANS fibers to the lacrimal gland, thus, can result in a dry eye
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What is dysfunction of the sympathetic fibers to the eye?
Horner's syndrome
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List the cardinal signs of Horner's syndrome
- Miosis (small pupil)
- Enophthalmos (small eyes)
- Ptosis (drooping eyelid)
- Protrusion of nictitating membrane
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What results in swelling or draining (pus) below the carnivore's eye?
Carnassial tooth abcess (upper premolar 4)
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How is aging of dog by their teeth used practically in dogs?
- Baby teeth in by 6 weeks: vaccination time
- Adult by 6 months: spay/neuter time
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Which dog teeth have three roots?
Last 3 on top
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Which cat permanent teeth have 3 roots?
Upper PM 4 (carnassial)
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How is a nasogastric tube placed?
Through the nostril and the ventral nasal meatus or it will break the ethmoid turbinates, resulting in nasal bleeding (epitaxis)
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A laryngotomy to open the larynx goes through which paired muscles to expose the larynx?
Sternohyoid muscles, middle "strap" muscle
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The esophagus is accessible to surgery in the ____ half of the neck region on the _____ side.
caudal; left
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What surgical landmark indicates the ventral midline of the larynx?
Cricothyroideus or bowtie muscle
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Paralysis of what muscle results in 'roarers' in horses
Cricoarytenoideus dorsalis muscle
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How is a tranqulized dog intubated?
Gently pull the tongue rostrally, push the soft palate up with the endotracheal tube, hold the epiglottis down with the tube, direct tube between the vocal folds into the trachea
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What causes laryngeal paralysis (dogs and horses)?
Damage to the recurrent laryngeal nerve resulting in paralysis of the cricoarytenoideus dorsalis muscle, the only muscle to open the glottic cleft, producing a roaring sound when breathing
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What is a roarer?
Dog or horse with laryngeal paralysis due to the recurrent laryngeal nerve damage and resulting paralysis of the cricoarytenoideus dorsalis muscle
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