Cranial Nerves And Formina Of Skull

Front 1

Cranial Nerves (CN)

Back 1

1) there are 12 pairs of cranial nerves that emerge from the anterior/inferior brain. These are numbered with roman numerals, starting at the anterior brain and going posteriorly

Front 2

CN I

Back 2

Olfactory Nerve

Front 3

CN II

Back 3

Optic Nerve

Front 4

CN III

Back 4

Oculomotor Nerve

Front 5

CN IV

Back 5

Trochlear nerve

Front 6

CN V

Back 6

Trigeminal nerve

Front 7

CN VI

Back 7

Abducent nerve

Front 8

CN VII

Back 8

Facial Nerve

Front 9

CN VIII

Back 9

Vestibulocochlear Nerve

Front 10

CN IX

Back 10

Glossopharyngeal Nerve

Front 11

CN X

Back 11

Vagus Nerve

Front 12

CN XI

Back 12

Accessory Nerve

Front 13

CN XII

Back 13

Hypoglossal Nerve

Front 14

Cranial Nerves x 12

Acronym

Back 14

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Front 15

CN I Olfactory Nerve

Back 15

a) consists of many small bundles of nerve fibers passing from olfactory epithelium of the superior nasal cavity, through cribiform plate of ethmoid bone to enter olfactory bulb on base of anterior brane

Front 16

CN II Optic Nerve

Back 16

a) from retina of eye, the optic nerve passes through the optic foramen to enter cranial cavity
b) right and left optic nerves come together at base of brain to form optic chiasma
1) location where visual nformation from one side of visual field crosses over to opposite side of brain
c) optic tract - pathway from optic chiasma to thalamus (synaptic relay center)
d) thalamic neurons send visual information to primary visual cortex of occipital lobe - cortical area that surrounds calcarine sulcus

Front 17

CN III Oculomotor Nerve

Back 17

a) exits cranial cavity via superior orbital fissure and enters orbit
b) motor output to:
1) levator palpabrae superioris - muscle tha elevates upper eyelid (palpabae)
2) four extraocular muscles that move eyeball: superior rectus, medial rectus, inferior rectus, & inferior oblique muscles
c) carries preganglionic parasympathetic fibers
1) preganglionic fibers synapse in ciliary ganglion (parasympathetic terminal ganglion located within orbit immediately posterior to eyeball)
2) postganglionic parasympathetic fibers activate muscles that constrict pupil and adjust lens for near viewing

Front 18

CN IV Trochlear Nerve

Back 18

a) exits cranial cavity via superior orbital fissure and enters orbit
b) motor to superior oblique extraocular muscle (muscle that passes through trochlea)

Front 19

CN V Trigeminal Nerve

Back 19

largest of all cranial nerves
- divides in cranial cavity into 3 divisions: Ophthalmic (V1), maxillary (V2), & mandibular (V3)
- each division exits cranial cavity through a seperate opening
- after exiting cranial cavity, each division divides into several named nerves

Front 20

CN V Trigeminal Nerve

Opthalmic Division V1

Back 20

sensory only; exits via superior orbital fissure to enter orbit;
a) sensory to forehead, eyeball, upper eyelid, sphenoid & ethomoid sinus, and superior part of nasal cavity
b) terminal branch = Supraorbital Nerve; passes along roof of orbit & exits skull via supraorbital foramen (notch); snsory to forehead

Front 21

CN V Trigeminal Nerve

Maxillary Division V2

Back 21

sensory only; exits via foramen rotundum; enters maxillary bone
a) sensory to lower eyelid, lateral face, cheek, upper lip, hard & soft palates, inferior nasal cavity, upper teeth & gums, & maxillary sinus
b) terminal brach = infraorbital nerve; runs along floor of orbit & exits via infraorbital foramen - sensory to anterior cheek and upper lip

Front 22

CN V Trigeminal Nerve

Mandibular Division V3

Back 22

motor and sensory; exits via foramen ovale & enters infratemporal fossa region (deep to mandible, inferior to zygomatic arch)
a) motor to muscles of mastication, mylohyoid muscle, & anterior belly of digastric muscle
b) general sensory to lower jaw and teeth, chin, lateral cheek, external ear, lateral scalp, and anterior 2/3 of tongue
c) terminal branches = inferior alveolar and mental nerves
1) inferior alveolar nerve enters mandibular foramen and runs through mandibular canal within body of mandible
2) sensory to teeth of lower jaw (alveolar = L, "hole or socket"; refers to teeth)
3) exits mental foramen as mental nerve - sensory to chin area (mental = L, "chin")

Front 23

CN VI Abducent Nerve

Back 23

a) exits cranial cavity via superior orbital fissure and enters orbit
b) motor to lateral rectus extraocular muscle (muscle that abducts eye)

Front 24

CN VII Facial nerve

Back 24

a) in posterior cranial fossa, enters internal acoustic meatus (with vestibulocochlear nerve CN VIII)
b) passes through temporal bone and exits base of skull at sylomastoid foramen
1) sends motor branches to stylohyoid muscle and posterior belly of digastric muscle (are not muscles of facial expression)
c) main nerve trunk continues through parotid gland, where it divides into several branches
1) branches fan out across face and neck to supply muscles of facial expression
d) facial nerve - taste fibers for anterior 2/3 of tongue
e) facial nerve - preganglionic parasympathetic innervation to mandibular & sublingual salivary glands

Front 25

CN VIII Vestibulocochlear Nerve

Back 25

sensory only;
a) exits cranial cavity via internal acoustic meatus - runs to inner ear
b) vestibular part - carries equilibrium & balance sensory information from vestibular apparatus (semicircular canals) of inner ear
c) cochlear part - auditory sensory information (hearing) from cochlea of inner ear

Front 26

CN IX Glossopharyngeal Nerve

Back 26

sensory, motor, taste & parasympathetic innervation:
a) exit cranial cavity via jugular foramen
b) taste & general sensory innervation of posterior 1/3 of tongue
d) preganglionic parasympathetic innervation for parotid salivary gland

Front 27

CN X Vagus Nerve

Back 27

motor, parasympathetic, visceral afferent innervations:
a) exits cranial cavity via jugular foramen then descends within carotid sheath through neck with common carotid & internal jugular vein. (vagus = L; "wandering")
b) motor innervation to muscles of pharynx and larynx
c) preganglionic parasympathetic innervation to heart, lungs, esophagus, stomach, liver, pancreas, spleen, kidneys, small intestine, and first 1/2 of large intestine
d) visceral sensory innervation from pharynx, larynx, & orgns that receive parasympathetic supply from vagus nerve

Front 28

CN XI Accessory Nerve

Back 28

motor only
a) exits cranial cavity via jugular foramen
b) motor to sternocleidomastoid muscle of neck
c) motor to trapezius muscle of superficial back

Front 29

CN XII Hypoglossal Nerve

Back 29

motor only
a) exits cranial cavity via hypoglossal canal
b) motor to muscles of tongue (glossus = "tongue")

Front 30

Foramen or Canal

Cribiform Plate

Back 30

Associated Nerve or Blood vessel

CN I Olfactory Nerve

Front 31

Foramen or Canal

Optic Foramen

Back 31

Associated Nerve or Blood vessel

CN II Optic nerve

Front 32

Foramen or Canal

Superior Optical Fissure

Back 32

Associated Nerve or Blood vessel

1) CN III Oculomotor N.
2) CN IV Trochlear N.
3) CN VI Abducent N.
4) CN V 2 Opthalmic Divison of Trigeminal N.

Front 33

Foramen or Canal

Supraorbital Foramen (Notch)

Back 33

Associated Nerve or Blood vessel

Supraorbital N. (Terminal branch of CN V 1 Opthalmic Division)
Supraorbital Artery

Front 34

Foramen or Canal

Foramen Rotundum

Back 34

Associated Nerve or Blood vessel

CN V 2 Maxillary division of Trigeminal N.

Front 35

Foramen or Canal

Infraorbital Foramen

Back 35

Associated Nerve or Blood vessel

Infraorbital N. (terminal branch of CN V 2 maxillary Division)
Infraorbital Artery

Front 36

Foramen or Canal

Foramen Ovale

Back 36

Associated Nerve or Blood vessel

CN V 3 Mandibular Division of Trigeminal Nerve

Front 37

Foramen or Canal

Mandibular Foramen & Canal

Back 37

Associated Nerve or Blood vessel

Inferior Alveolar Nerve (from CN V 3 - Mandibular division of trigeminal n)
Inferior Alveolar Artery

Front 38

Foramen or Canal

Mental Foramen

Back 38

Associated Nerve or Blood vessel

Mental Nerve (terminal branch of Inferior Alveolar Nerve from CN V 3 - Mandibular Division of Trigeminal N)
Mental Artery (branch of inferior alveolar A.)

Front 39

Foramen or Canal

Internal Acoustic Meatus

Back 39

Associated Nerve or Blood vessel

1) CN VIII Vestibulocochlear N.
2) CN VII Facial N. (where facial n enters temporal bone)

Front 40

Foramen or Canal

Styloidmastoid Foramen

Back 40

Associated Nerve or Blood vessel

CN VII Facial N. (where facial N exits temporal bone)

Front 41

Foramen or Canal

Jugular Foramen

Back 41

Associated Nerve or Blood vessel

1) CN IX Glossophayngeal N
2) CN X Vagus N
3) CN XI Accessory N
4) beginning of internal jugular vein

Front 42

Foramen or Canal

Hypoglossal Canal

Back 42

Associated Nerve or Blood vessel

CN XII Hypoglossal N

Front 43

Foramen or Canal

Foramen Magnum

Back 43

Associated Nerve or Blood vessel

1) Spinal Cord
2) Vertebral Arteries

Front 44

Foramen or Canal

Carotid Canal (entrance)

Back 44

Associated Nerve or Blood vessel

Internal Carotid A. (artery follows zig-zag path through base of skull before emerging lateral to sella turcica)

Front 45

Foramen or Canal

Foramen Spinosum

Back 45

Associated Nerve or Blood vessel

Middle Meningeal Artery

Front 46

Foramen or Canal

Foramen Lacerum

Back 46

Associated Nerve or Blood vessel

in life, filled with cartilage; nothing passed through this opening

Front 47

Foramen or Canal

Nasolacrimal canal

Back 47

Associated Nerve or Blood vessel

for drainage of tears from medial eye into nasal cavity

Front 48

Cervical Plexus

Back 48

formed by ventral rami of spinal nerves C1- C4
a) provide cutaneous innervation for neck and superior shoulder regions
b) motor innervation to infrahyoid muscles
c) contributes to formation of Phrenic Nerve (C3 - C5) - motor nerve to thoracic diaphragm

Front 49

Brachial Plexus

Back 49

formed by ventral rami of spinal nerves C5 - T1 - innervates upper limb
a) nerves of brachial plexus pass through interscalene triangle with subclavian artery (pass between anterior and posterior-middle scalene muscles)

Front 50

Salivary Glands

x 3

Back 50

1) Parotid Gland - located posterior to ramus of mandible
2) Submandibular gland - under mandible, near junction of two bellies of digastric muscle
3) Sublingual salivary gland - in floor of oral cavity, lateral to root of tongue

Front 51

Autonomic Innervations of Salivary Gland

Sympathetic Innervation

Back 51

1) Parotid Gland
a) sympathetic innervation to parotid gland
1) Preganglionic sympathetic neuron cell bodies in T1-L2 spinal cord
2) postganglionic sympathetic neuron cell body in superior cervical ganglion of sympathetic trunk
3) postganglionic fibers run with common carotid artery then external carotid artry to reach parotid gland

Front 52

Autonomic Innervations of Salivary Gland

Parasympathetic Innervation

Back 52

b) parasympathetic innervations to parotid gland
1) axon of preganglionic parasympathetic neuron exits brain with glossopharyngeal Nerve CN IX
2) synapses onto postganglionic parasympathetic neuron in terminal ganglion located near parotid gland (don't need to know specific name of ganglion)
3) postganglionic parasympathetic neuron innervates parotid gland

Front 53

Submandibular & Sublingual Glands

Sympathetic Innervation

Back 53

a) sympathetic innervation to submandibular and sublingual glands
1) preganglionic sympathetic neuron in T1-L2 spinal cord
2) postganglionic sympathetic neuron cell body located in superior cervical ganglion of sympathetic trunk
3) postganglionic fibers run with common carotid artery , external carotid artery, and lingual artery to reach sublingual gland

Front 54

Submandibular & Sublingual Glands

Parasympathetic Innervation

Back 54

b) parasympathetic innervation to submandibular and sublingual glands
1) axon of preganglionic parasympathetic neuron exits brain with Facial Nerve CN VII
2) synapses onto postganglionic parasympathetic neuron in submandibular ganglion (terminal ganglion located deep, posterior oral cavity, near both glands)
3) postganglionic parasympathetic neurons innervate submandibular and sublingual glands