26.neuro_exam

Question 1

6 parts of a neuro exam

Answer 1

1. sensorium and behavior2. posture and gait3. postural reactions4. spinal reflexes, muscle mass, muscle tone5. cranial nerves6. cutaneous sensation

Question 2

obtunded vs stupor vs coma

Answer 2

—obtunded—decreased arousal in response to touch/voicedepression—stupor—arousable to vigorous stimuli but response is incomplete or inadequate–coma—sustained unresponsiveness to stimuli

Question 3

alteration in sensorium is typically due to what disturbances

Answer 3

1. disturbance in the ascending reticular activating system2. disturbance in cerebrum3. disturbance in the limbic system (cerebrum/brainstem–diencephalon)suggests intracranial disease

Question 4

define lower motor unit

Answer 4

1. ventral horn cell2. axons of peripheral nervous system3. NMJ4. innervated muscle

Question 5

decerebrate vs decerebellate rigidity

Answer 5

both indicate disruption of descending inhibitory influence on the nerves going to extensor musclesdecerebrate—opisthotonous, mentation changes/menace, rigid neck x 4 limbs—-indicate midbrain or rostral cerebellar lesiondecerebellate—opisthotonous, do not always affect mentation, rigid neck x 4 limbs but hind limbs FLEXED—-indicate SEVERE cerebellar lesion

Question 6

area of nervous system leading to gait abnormalities

Answer 6

midbrainstem and caudal (caudal brainstem, spinal cord, peripheral nerve)ataxia (vestibular, cerebellar, proprioception)weakness (can be UMN or LMN)lameness (LMN or ortho)

Question 7

T/Fchronic structural changes in prosencephalon do NOT result in obvious gait abN

Answer 7

TRUEchronic structural changes in prosencephalon do NOT result in obvious gait abN

Question 8

variation in LMN paresis/gait

Answer 8

mild-moderate LMN dz: ambulatory with short, choppy, stilted gaitSevere LMN dz: non ambulatory or tetraplegicnot usually ataxic bc GP pathways are unaffected

Question 9

modified franked scoring

Answer 9

0 plegia with no deep pain1 plegia with no superficial pain2 plegia with nociception intact3 nonambulatory paresis4 ambulatory paresis , ataxic5 spinal hyperesthesia only

Question 10

variation in UMN paresis/gait

Answer 10

long strided, spastic gaitgeneral proprioceptive ataxia

Question 11

why is it difficult to separate general proprioceptive ataxia vs UMN dz

Answer 11

adjacent pathway anatomicallytherefore it is difficult to separate the effect on gait caused by dysfunction of descending UMN path vs dysfunction of ascending proprioceptive pathwaysdogs w only proprioceptive ataxia are assumed to have UMN dz

Question 12

T/Fanimals with LMN dz/neuromuscular dz actually have NORMAL postural rxn

Answer 12

TRUEanimals with LMN dz/neuromuscular dz actually have NORMAL postural runbecause a LACK of disruption of general ascending proprioceptive pathways. Therefore, rely on spinal reflexes to dx

Question 13

what do normal postural run depend on

Answer 13

intact conscious AND UNCONSCIOUS proprioception and intact UMN and LMNSENSORY –>DORSAL HORN (IPSILATERAL SPINAL CORD TO MIDBRAIN Unconscious Proprioception, CONTRALAT PROESNCEPHLAON Conscious Proprioception)

Question 14

T/Fa dog with NM dz (ie. myasthenia gravis) may still have proprioceptive deficits

Answer 14

TRUEeven though the lesion is NOT in the proprioceptive pathway the dog is too weak to return paw to normal anatomic position

Question 15

most reliable spinal reflexes

Answer 15

patellar withdrawal

Question 16

patellar reflex

Answer 16

L4-L6femoral nstifle extension(maybe abN in older dogs without signs of neuro dz)

Question 17

the finding of an absent or hyporeflexia spinal reflex indicates a problem where?

Answer 17

1. afferent limb2. efferent limb3. spinal cord segment involved in reflex arc

Question 18

the finding of a hyper reflexive spinal reflex indicates a problem where?

Answer 18

lesion cranial to the spinal cord segment containing the reflex arc

Question 19

biceps and triceps spinal reflex

Answer 19

biceps reflex–musculocutaneous n (C6-8)–slight flexion of elbow, and movement over muscletriceps reflex–radial n (C7-T2)–slight extension of elbow, contraction of triceps

Question 20

pelvic vs thoracic withdrawal spinal reflex

Answer 20

pelvic withdraw–sciatic n (L6-S1)thoracic withdraw–brachial plexus n (C6-T2)(S-S)-M-A-R-M-UComplete flexion of all joints!!

Question 21

stance of dogs with sciatic nerve injury

Answer 21

PLANTIGRADE due to tibial nerve dysfunction (which is a branch of sciatic, courses medially to innervate gastrocnemius muscle)PAW MISPLACED ONTO DORSUM due to peroneal nerve dysfunction (which is a branch of sciatic, courses laterally to cranial tibialis muscle)LMN dz BUT pelvic limb is not usually short strided but rather exaggerated and “flings” foot forwardlimb will be able to support weight if femoral nerve is intact bc stifle can be extended to bear weight; hip is flexed

Question 22

where do the median and ulnar nerves innervate

Answer 22

PALMAR

Question 23

where does the ulnar nerve innervate

Answer 23

LATERAL aspect of DIGIT 5

Question 24

where does radial nerve innervate

Answer 24

dorsum of footcranial and lateral antebrachium

Question 25

where do ulnar and musculocutaneous nerves innervate

Answer 25

caudal and medial antebrachium (ulnar n) and brachium (musculocutaneous n )

Question 26

where do perineal and tibial branches of the sciatic nerve innervate

Answer 26

dorsal (peroneal n ) and plantar (tibial n)

Question 27

where does the saphenous branch of femoral nerve innervate

Answer 27

medial aspect of pelvic limb (digit 1)in some patients, innervation by the saphenous nerve is not present distally.

Question 28

perineal spinal reflex

Answer 28

sacral and caudal branches of pudendal nerveS1-S3

Question 29

Cutaneous trunci reflex

Answer 29

sensory input via dermatomes lateral thoracic nerve C8-T1—>cutaneous trunci musclereflex is preserved for 1-2 vertebral bodies caudal to the level of the spinal cord lesion

Question 30

cranial nerves

Answer 30

ooottafvgvah pg 332olfactoryopticoculomotortrochleartrigeminalabducensfacialvestibularglossopharyngealvagus accessoryhypoglossal

Question 31

menace reflex

Answer 31

most reliable for visiontests 2 optic, 7 fascial innervation orbicularis oculi mlearned response 10-12 wk of age

Question 32

why does an indirect PLR occur

Answer 32

PLR tests 2 optic, 3 oculomotor nindirect/consensual response occurs bc crossing over fibers at optic chasm and pretectal nuclei to stimulate parasympathetic oculomotor nerve and iris muscle–> constriction of pupil

Question 33

horners syndrome

Answer 33

loss of sympathetic innervation to the eye1. ptosis2, third eyelid elevation3. miosis4. enophthalmos

Question 34

course of autonomic nervous system four sympathetic fibers

Answer 34

preganglionic neuron–CNS (throughout TL spinal cord, join vagus/vagosympathetic trunk,ascend in sheath to cranial cervical ganglion)post ganglionic neuron–PNS (synapse at CC ganglion–near bullae, go to cranium via ophthalmic branch of trigeminal n to innervate muscle)effector muscle (muscle innervated dilator muscle of the pupil in the iris)

Question 35

ventrolateral strabismusmedial strabismuseyeball extorsion with CN dysfunction

Answer 35

ventrolateral strabismus–oculomotor n dysfunction (3)medial strabismus–abducens n dysfunction (6)eyeball extorsion–trochlear n dysfunction (4)trochlear dysfunction in cats also displays itself as lateral rotation of the dorsal aspect of the pupil

Question 36

palpebral reflex

Answer 36

5 trigeminal sensory (branches ophthalmic medially maxillary lateral)7 facial motor (branch–palpebral)

Question 37

trigeminal sensory function is tested with

Answer 37

nasal sensation 1. ipsilateral branch of ophthalmic and maxillary2. nociceptive path to contralateral thalamus / cortex

Question 38

what nerves control the GAG reflex

Answer 38

glossopharyngealvagushypoglossal

Question 39

how many spinal cord segments C, T, L, S

Answer 39

cervical 8thoracic 13lumbar 7sacral 3at least 2 caudal coccygealC1-5 C6-T2 (cervicothoracic intumescence) T3-L3 L4-S3 (lumbosacral intumescence)

Question 40

typical gait for C6-T2 lesions

Answer 40

2 engine gaitthoracic limbs–short choppy (LMN)pelvic limbs–long strides (UMN) with GP ataxia

Question 41

when is schiff-sherrington syndrome seen

Answer 41

peracute T3-L3 lesionsmarked increased extensor tone in thoracic limbsdue to disruption in ascending inhibitory axons arising from interneurons

Question 42

describe spinal shock

Answer 42

may occur as T3-L3 lesions in which pelvic limbs display LMN signsdue to transient disconnection btwn the facilitatory descending UMN that modulate function of LMN of the LS intumescence and the spinal neurons

Question 43

NM or LMN diseases

Answer 43

localized to NMJ, nerves (neuropathy) or muscles (myopathy); can be focal, multifocal, or diffusemay need ancillary testingCK, AST, electrolytesTick borne disease panelsTensilon testingAch Ab titerNerve/Muscle bxEMG