Introduction toIntroduction to

Neurology Neurology

Prof. Mamun SarhanProf. Mamun SarhanHead of NeurologyHead of Neurology DepartmentDepartment

WHAT IS NEUROLOGY?

Neurology is the branch of medicine that deals with diseases of the nervous system.

Major divisionsMajor divisions

NervousNervousSystemSystem

CentralCentral nervousnervous systemsystem

PeripheralPeripheralnervousnervoussystemsystem

1.Cerebrum 2. Brain stem 3. Cerebellum

Intracranial part

Intracranial part

Spinal part

Spinal part

Spinal cord &

Cauda equina

Cerebrum

Two cerebral hemispheres Connected to:

1. each other by corpus callosum

2. brain stem by cerebral peduncles

EACH CEREBRAL HEMISPHEREDEVIDED INTO :

four lobes: 1. Frontal

2. Parietal

3. Temporal

4. Occipital

Brain stem

Formed of :

Midbrain

Pons

Medulla

Connected to:

1. Cerebral hemisphere

by cerebral peduncles

2. Cerbellum by cerebellar

peduncles

Contains:

• CN 3,4 in midbrain

• CN 5,6,7,8 in pons

• CN 9,10,11,12 in medulla

Names of cranial nerves• Ⅰ Olfactory nerve • Ⅱ Optic nerve • Ⅲ Oculomotor nerve • Ⅳ Trochlear nerve• Ⅴ Trigeminal nerve • Ⅵ Abducent nerve • Ⅶ Facial nerve • Ⅷ Vestibulocochlear

nerve • Ⅸ Glossopharyngeal nerve• Ⅹ Vagus nerve • Ⅺ Accessory nerve • Ⅻ Hypoglossal nerve

Classification of cranial nerves• Sensory cranial nerves: contain only afferent (sensory) fibers

– ⅠOlfactory nerve – ⅡOptic nerve– Ⅷ Vestibulocochlear nerve

• Motor cranial nerves: contain only efferent (motor) fibers– Ⅲ Oculomotor nerve – Ⅳ Trochlear nerve – ⅥAbducent nerve – Ⅺ Accessory nerv – Ⅻ Hypoglossal nerve

• Mixed nerves: contain both sensory and motor fibers--- – ⅤTrigeminal nerve, – Ⅶ Facial nerve,– ⅨGlossopharyngeal nerve– ⅩVagus nerve

Sensory cranial nerves

N. Name Function Assessment

Ⅰ Olfactory Smell Examination of smell

Ⅱ optic Vision Acuity, field & fundus

Ⅷ Vestibular part

Equilibrim Caloric and rotational chair

Cochlear part

Hearing Watch test, weber test

Motor cranial nervesN. Name Function Assessment

Ⅲ Oculomotor Motor to superior, inferior and medial recti; inferior oblique & levator palpebrae superioris

Ptosis, pupil, eye movements & squint

Parasympathetic to sphincter papillae and ciliary muscle

Ⅳ Trochlear Motor to superior oblique Look to opposite shoulder

Ⅵ Abducent Motor to lateral rectus Lateral eye movement

Ⅺ Accessory Motor to sternocleidomastoid and trapezius

Elevaton of shoulders and neck rotation

Ⅻ Hypoglossal Motor to muscles of tongue Tongue movements

Mixed cranial nervesN. Name Function Assessment

V Trigeminal Muscles of mastication & sensations of face

Face sensations & power of muscles of mastication

VII Facial Muscles of facial expression & taste sensation in ant. 1/3 of tongue

Muscles of facial expression & taste sensation in ant. 1/3 of tongue

X Vagus Sensation and movements of Larynx, pharynx, thoracic and abdominal organs

Palatal and pharyngeal reflexes & movements of uvula

XII Glossopharyng-eal

Taste in post 2/3 of tongue & gen. sensation

Taste & general sensation and pharyngeal reflex

Cerebellum

• Behind the brain stem

• Formed of : medline vermis

two cerebellar hemispheres

• Composed of :

outer grey matter and inner

White matter

MBMB

PonsPons CC

MOMO

Superior peduncle connects cerebellum with midbrain. Middle peduncle connects cerebellum with pons. Inferior peduncle connects cerebellum with medulla oblongata

Cerebellar peduncles

lefthemisphere

righthemisphere

Hemispheres and vermis

Cerebellar hemispheres are the two bilateral structures.Vermis is the unpaired midline structure between

the two hemispheres.

vermis

Spinal cord

• Inside spinal canal

• End at lower border of L1

• The lowest 3 segments = Conus

• The above 4 segments = Epiconus

• Inner grey matter and outer white matter

Cauda equina

• Lumbosacral roots collection fills

the lower part of the spinal canal

bellow L1

Cauda equinaBrachial plexusLumbosacral plexusCervical enlargementLumbosacral enlargement

Peripheral nervous system

• A.H.Cs

• Roots

• Plexuses

• Peripheral nerves

Medulla

motor cortex

internal capsule

Uppermotorneuron

Lowermotorneuron

anterior horn cell

Motor pathway

UMNL LMNL

Tone Increased, with ‘clasp knife’ quality

Decreased

Clonus Present Absent Fasciculations Absent Present Muscle Wasting Absent, but disuse

atrophy eventually results

Present (within 2-3 weeks)

Tendon Reflexes Increased. Extensor plantar reflexes.

Decreased or absent. Flexor plantar reflexes.

Distribution Whole limbs, with more weakness in the upper limb extensors and lower limb flexors

Specific muscle groups affected (e.g. in the distribution of a spinal segment, or just the proximal muscles, etc.)

Thank You!!!