BRAIN POWER!

“Any fool can know. The point is to understand.”

-Albert Einstein

Chapter 8

CHAPTER 8

DISEASES OF THE NERVOUS SYSTEM

Neurological Diseases

PNS

Anatomy of the Nervous System

• Central Nervous System (CNS)– Brain, spinal cord

• Peripheral Nervous System (PNS-Links CNS to body)– Cranial nerves (from brain)– Peripheral nerves (from spinal cord)

• Autonomic nervous system controls smooth muscle and cardiac muscle – Parasympathetic vs. Sympathetic Nervous system

• Somatic (voluntary) system – skeletal m.

Cranial nerves

NUMBER NAME TYPE KEY FUNCTION

I Olfactory S Smell

II Optic S Vision

III Oculomotor M Eye movement, pupil size, focusing lens

IV Trochlear M Eye movement

V Trigeminal B Sensations – head & teeth; chewing

VI Abducent M Eye movement

VII Facial B Face and scalp movement, salivation, tears, taste

VIII Vestibulocochlear S Balance, hearing

IX Glossopharyngeal B Tongue movement, swallowing, salivation, taste

X Vagus B Sensory from: GI, respiratory; Motor: larynx, pharynx, parasympathetic, abdomen and thoracic

organs

XI Accessory M Head movement, accessory motor with vagus

XII Hypoglossal M Tongue movement

Mneumonics

• Olfactory, Optic, Oculomotor, Trochlear, Trigeminal, Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal

– “Oh, Oh, Oh, To Touch And Feel Various Girl's Very Angelic Hands”

– “Some Say Marry Money, But My Brother Says Big Business Makes Money”

Neurological Exam

• Observe– Attitude, mentation (alert, lethargic, coma, etc),

Gait• Agitation, anxiety• Seizures

– Posture (Higher center)• Upright or sternal• Head tilt (vestibular?VIII)• Wide based stance (ataxia, weakness)

Neuro Exam• Gait– Walking and running on flat, non-slippery surface• Walk slowly back and forth with turns and circles

– Proprioceptive deficits (knuckling)-spinal cord defect– Paresis (weakness)/paralysis (no movement) – cerebral

cortex, brainstem, spinal cord or peripheral spinal nerves or muscles

– Circling/pacing – • Tight circling with head tilt – vestibular (VIII)• With dementia – ipsilateral cerebral cortex

Posterior Paresis

• Reflexes present or exaggeratedin the rear legs if lesion is betweenT3-L3• Reflexes arediminished orabsent in the rear legs if lesion is betweenL4-S2

Neuro Exam– Ataxia/incoordination – cerebellum, vestibular

system, or spinal cord

– Dysmetria - cerebellar• Hypermetria – too long movements• Hypometria – movements too short

http://www.youtube.com/watch?v=0QOKPFMt0Rc&feature=endscreen&NR=1

Neurologic Exam

•Cranial Nerves- I (S) Olfactory: ether /alcohol on cotton—will pull away- II (S) Optic: follow moving objects; drop cotton ball- III (M), IV (M), VI (M) Oculomotor, trochlear, abducent: look up, down, sideways- V (B) Trigeminal: sensory to face, motor to muscles of mastication, weakness in jaw muscles

Neurologic Exam–VII (M) Facial: unilateral droop; drool; no

menace–VIII (S) Vestibulocochlear: balance

(nystagmus, head tilt); hearing– IX (B), X (B), XI (M) Glossopharyngeal, Vagus,

Accessory: swallowing; muscle atrophy–XII (M) Hypoglossal: loss of tongue

movement; unilateral atrophy

Neuro Exam – Cranial Nerves• Blind II• No menace II/VII• Anisocoria II, III• Atrophy of temporal muscles V

• Dropped jaw V• Nares, lip pinch, cornea V

– Inside ear• Lip/ear droop VII• No blink VII• Head tilt VIII

Neuro exam – Cranial Nerves

• Nystagmus VIII• Deafness VIII• Difficulty swallowing IX, X• Loss of gag reflex IX, X• Laryngeal paralysis IX, X• Weakness, asymmetry of tongue XII

Cranial nerve

• http://www.youtube.com/watch?v=S8f9-GPW9IE&feature=related

Female Brain

Male Brain

Neuro Exam

• Postural reactions–Knuckling–Hopping–Wheelbarrowing–Hemiwalking

http://www.youtube.com/watch?v=IXpGX6xhJdM

Knuckling

Neuro Exam• Muscle Tone– Atrophy – occurs slowly from disuse• Rapidly from nerve damage

– Lower Motor Neuron signs – decreased reflexes and muscle tone (spinal cord)

– Upper Motor Neuron – reflexes & muscle tone increased (brain)

– Test by flexing/extending joints

Neuro exam – Spinal Reflexes

• Thoracic limb withdrawal – pinch toe• Patellar – strike patellar ligament – extension of

stifle• Pelvic limb withdrawal – pinch toe • Sciatic – Strike between greater trochanter and

ischium – flexion of stifle and hock• Cranial tibial – strike cranial tibial m just below

proximal end of tibia – flex hock• Perineal – pinch perineum/anus – anal sphincter

contraction, tuck tail• Panniculus – stimulate skin over dorsum just lateral

to vertebral column – twitch of cutaneous trunci m.

Neuro Exam: Upper Motor Neuron vs. Lower Motor Neuron signs

UMNLMN• Muscle tone N or I D• Spinal reflexes N or I D• Motor fxn Spastic Flaccid• Muscle atrophy Mild Severe• disuse neuro• Bladder Tense Flaccid

Patellar Reflex

Patellar Reflex

Reflex examination

• http://www.youtube.com/watch?v=NFqFABsIa7Q&feature=related

Pelvic Limb Withdrawal – Or Not

Panniculus Test