This document provides an overview of the brain, cranial nerves, and their anatomy and functions. It begins with an introduction and outline of topics to be covered, including the main parts and protective coverings of the brain. It then describes each of the 12 pairs of cranial nerves in detail, including their names, numbers, points of exit from the brainstem, classification based on innervation and function, and mnemonics to remember their functions. The document concludes with descriptions of the foramina through which the cranial nerves exit the skull.

1. BRAIN &
CRANIAL
NERVE
Prepared By:
Dr.Hemal R. Brahmkshatriya
MDS PartI

2. Under guidance of:
 Dr. Kiran Desai sir
 Dr. Navin Shah sir
 Dr. Rakesh Shah sir
 Dr. Kruti Shah mam
 Dr. Amit Mahajan sir
 Dr. Dixit Shah sir
 Dr. Rohit Tatu sir
 Dr. Prachur Kumar sir
 Dr. Rushit Patel sir

3. CONTENTS
 Introduction
 Brain
 Cranial nerve
 Cranial nerve vs Spinal Nerve
 Topography of nerves.
 Functional Anatomy of Cranial nerves.
 Examination of Cranial nerves.
 Surgical Aspects of Nerves.

4. Central Nervous System

6. Parts of Brain:
1. Forebrain
(prosencephalon)
a) Telencephalon (cerebrum)
b) Diencephalon
(thalamecephalon)
2. Midbrain
(mesencephalon)
3. Hindbrain
(rhombencephalon)
a) Metencephalon (pons+
cerebellum)
b) Myelencephalon or
medulla oblongata.

7. Cerebrum
 Anatomy
 Frontal lobe
 Parietal lobe
 Occipital lobe
 Precentral gyrus
 Postcentral gyrus
 Functions
 Sensory cortex
 Motor cortex
 Emotion
 Intellectual processes
 Auditory
 Visual
 Speech

8. Brain Stem
 Anatomy:
 Medulla oblongata
 Pons
 Midbrain
Medulla:
-Relays motor and
sensory information.
-Regulates heartbeat,
breathing and blood
vessel dilation.
 Pons: Control breathing.
 Mid Brain:
 vision, hearing,
motor control,
sleep/wake, arousal
(alertness), and
temperature
regulation

13. Protective Coverings
(Meninges)
 Dura mater:
Dense connective tissue.
 Arachnoid:
Nonvascular connective tissue.
 Pia mater:
Highly vascular.
Covers surface of the brain and spinal cord and
invaginates along cortical surface to form
perivascular spaces.

15. Cerebral Spinal Fluid
 Formed in the choroid plexus of leteral ventricles
and 3rd and 4th ventricles, capillaries of brain and
spinal cord.
 Total contain 150 ml formation rate 500ml/day.
 Absorbed arachnoid villi layer to cranial venous
sinus, spinal nerve.
 Protects, nutritive and pathways for metabolisum.

17.  Nerves that emerge directly from the
brain (spinal nerves emerge from
segments of the spinal cord).
 12 pairs of cranial nerves.!!!!!?

19.  Numbered Anterior to Posterior
 Attach to Ventral surface of brain
 Exit brain through foramina in skull
 I + II attach to Forebrain
 III-XII attach to Brainstem (midbrain, pons,
medulla)
 Only X goes beyond the head-neck

22. Cranial nerve v/s spinal nerve
 Contain inflow/outflow of brain; spinal nerves contain
inflow/outflow of spinal cord.
 Certain types of similar to those found in spinal nerves; ex.
Sensory axons to skin.
 Certain types of neurons not found in spinal nerves; ex. taste
fibers.
 Many cranial nerves contain more than one type of neuron.

23. BASIS OF CLASSIFICATION
1) First letter: G = General = types of neurons found both in
spinal nerves and cranial nerves.
S = Special = types of neurons only found in
cranial nerves not spinal nerves.
2) Second letter: S = Somatic = types of neurons innervating
structures derived from somites.
V = Visceral = types of neurons innervating
gut, structures derived from or associated with gut and brachial
arches; also vascular system, smooth muscle, internal organs
and glands.
3) Third letter: A = Afferent = sensory neurons.
E = Efferent = motor neurons to skeletal and
smooth muscle; also secretomotor neurons to glands.

24. A. General Innervation - like spinal cord
1. GSE (General Somatic Efferent) - motor to somatic
voluntary skeletal muscles (derived from somites).
2. GSA (General Somatic Afferent) - sensory to skin,
joints, muscle and tendon receptor endings, nasal and oral cavity.
3. GVE (General Visceral Efferent) = Autonomic
Efferents - motor to smooth muscles in general and smooth
muscles of skin (arrector pilae muscles) and blood vessels,
secretomotor to glands.
4. GVA (General Visceral Afferent) - sensory to gut and its
derivatives, pharynx, blood vessels, glands and internal organs.

25. B. Special Innervation - only found in head.
1. SSA (Special Somatic Afferent) - special senses of vision,
auditory sensation and vestibular apparatus.
2. SVA (Special Visceral Afferents) – chemical senses of taste
and by analogy smell.
3. SVE (Special Visceral Efferents) - motor to voluntary
skeletal muscles derived from branchial arches (these muscles
develop in association with pharynx, which is rostral end of gut
and therefore visceral).

27. Oh! Oh! Oh! To Touch And Feel Very Good
Velvet! At Heaven!
 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

28. According to functions
 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
Ⅵ Abducent nerve
Ⅺ Accessory nerve
Ⅻ Hypoglossal nerve

29.  Mixed nerves: contain both sensory and motor
fibers---
ⅤTrigeminal nerve
Ⅶ Facial nerve
ⅨGlossopharyngeal nerve
ⅩVagus nerve

30. Mnemonic for CN Function
I. Some
II. Say
III. Marry
IV. Money
V. But
VI. My
VII. Brother
VIII. Says
IX. Big
X. Brains
XI. Matter
XII. Most!
S = Sensory function
M = Motor
function
B = BOTH (Sensory
and Motor function

31. Cooks Out Spurt Some Spunk Right Over
Silly Isabel's Incredible Jiggling Jizz Jet
hole
 Cribiform plate (Olfactory)
 Optic canal (Optic)
 Superior Orbital
Fissure(Oculomotor)
 Superior Orbital
Fissure(Trochlear)
 Superior Orbital
Fissure(Trigeminal -
Ophthalmic)
 Foramen Rotundum
(Trigeminal- Maxillary),
 Foramen Ovale (Trigeminal -
Mandibular),
Superior Orbital Fissure
(Abducens)
• Internal Acoustic Meatus
(Facial)
• Internal Acoustic Meatus
(Vestibulocochlear)
• Jugular Foramen
(Glossopharyngeal)
• Jugular Foramen (Vagus)
• Jugular Foramen
(Accessory)
• Hypoglossal Canal
(Hypoglossal)