cranial nerves

• What are the cranial nerves?

  •12 pairs of nerves (left and right for each)

  •Come off brain and brain stem

  •Leave skull via little holes called foramina to supply regions of the face, neck and torso.

  •Some are sensory nerves, some are motor, and some are mixed (sensory and motor)
• What are the cranial nerves?

  •Your cranial nerves help you taste, smell, hear and feel sensations. They also help you make facial expressions, blink your eyes and move your tongue.
• What are the cranial nerves?

  •Four cranial nerves also have parasympathetic function: CN 3, 7, 9 & 10
• What are the cranial nerves?

  •Head injuries, tumours, bleeds on the brain etc can all affect the functioning of the cranial nerves. Clinicians perform cranial nerve exams to test the functioning of these nerves and rule out pathology.
• the 12 cranial nerves

  A) Olfactory

  B) optic

  C) Oculomotor

  D) Trochlear

  E) Trigeminal

  F) Abducens

  G) facial

  H) Vestibulocochlear

  I) Glossopharyngeal

  J) vagus

  K) Accessory

  L) Hypoglossal

  
• the cranial nerves

  A) olfactory

  B) optic

  C) oculomotor

  D) trochlear

  E) trigeminal

  F) abducens

  G) facial

  H) Vestibulocochlear

  I) Glossopharyngeal

  J) vagus

  K) Accessory

  L) hypoglossal

  
• to see which cranial nerve is sensory or motor or both

  SOME SAY MONEY MATTERS BUT MY BROTHER SAYS BIG BRAINS MATTER MORE
• SOME SAY MONEY MATTERS BUT MY BROTHER SAYS BIG BRAINS MATTER MORE

  Olfactory - S

  Optic - s

  Oculomotor - M

  Trochlear - M

  Trigeminal - B

  Abducens - M

  Facial - B

  Vestibulocochlear - S

  Glossopharyngeal - B

  Vagus - B

  Accessory - M

  Hypoglossal - M
• The extraocular muscles - CRANIAL NERVES EQUATION

  LR6 SO4 3

  Lateral rectus m.= CN6

  Superior oblique m.= CN4

  All other extraocular muscles =CN3

  
• The extraocular muscles

  A) Superior rectus

  B) lateral rectus

  C) inferior oblique

  D) superior oblique

  E) medial rectus

  F) inferior rectus

  
• What are the cranial nerves?

  A) olfactory

  B) sensory

  C) optic

  D) sensory

  E) oculomotor

  F) motor

  G) trochlear

  H) motor

  I) Trigeminal

  J) both

  K) Abducens

  L) motor

  M) facial

  N) both

  O) Vestibulocochlear

  P) sensory

  Q) Glossopharyngeal

  R) both

  S) vagus

  T) both

  U) Accessory

  V) motor

  W) Hypoglossal

  X) motor

  
• CN1 (I) OLFACTORY - Sensory (smell)

  ‘Old factories smell!’

  Exits cranial cavity via the: Cribriform plate

  
• OLFACTORY nerve

  A) olfactory bulb

  B) Cribriform plate

  C) olfactory filaments

  
• OLFACTORY nerve

  A) olfactory bulb

  B) Cribriform plate

  C) olfactory filaments

  
• olfactory passage

  A) Cribriform plate

  B) olfactory bulb

  
• CN2 (II) OPTIC - Sensory (vision)

  Optic nerve gives us vision!

  Exits cranial cavity via the: Optic canal

  
• Left optic canal opening viewed from external aspect of eye socket

  A) inferior orbital fissure

  B) superior orbital fissure

  C) optic canal

  
• Left optic canal opening viewed from superior intracranial aspect

  
• CN3 (III) Oculomotor - Oculo (eye) Motor (to move)

  Motor: movement of the eyeball up, down and medially, opens eyelids,

  Parasympathetic: pupil constriction and accommodation.

  Exits cranial cavity via the: Superior orbital fissure

  
• CN4 (IV) Trochlear

  Motor: Supplies the superior oblique muscle moves the eye downwards and outwards

  Exits cranial cavity via the: Superior orbital fissure

  
• Trochlear= latin for ‘pulley’

  Acts as a cartilaginous sling/pully which the tenson for superior oblique loops through.

  
• CN5 (V) Trigeminal

  Both: Sensory to areas of the face/scalp, corneas, nasal/oral cavities and the teeth!

  Motor supply to the M.O.M

  
• CN5 (V) Trigeminal

  Tri= 3

  Trigeminal has 3 divisions

  V1 (ophthalmic division) sensory to area in green

  V2 (maxillary division) sensory to area in pink

  V3 (mandibular division) sensory to area in purple and also provides motor innervation to the muscles of mastication (chewing!)

  
• CN5 (V) Trigeminal

  3 branches exist cranial cavity separately:

  V1 exists via: Superior orbital fissure

  V2 exits via Foramen Rotundum

  V3 exists via Foramen Ovale

  
• some openings

  A) optic canal

  B) Superior orbital fissure

  C) Foramen Rotundum

  D) Foramen Ovale

  
• CN5 (V) Trigeminal

  V3 Supplies the 4 muscles of mastication AKA chewing muscles!

  Note: there are 4 on the left side and 4 on the right so 8 in total
• CN5 (V) Trigeminal

  4 Muscles of Mastication (MoM)

  1. Temporalis

  2) Masseter

  3) Medial Pterygoid

  4) Lateral pterygoid

  Allow ‘Mastication’ aka chewing! Motor supply to make these muscles contract comes from V3 division of trigeminal nerve (cranial nerve 5)

  
• CN5 (V) Trigeminal muscle

  A) temporalis

  B) masseter

  C) Lateral pterygoid

  D) Medial Pterygoid

  
• CN5 (V) Trigeminal

  V2 provides sensation to the upper teeth

  V3 provides sensation to the lower teeth

  
• CN6 (VI) abducens - LR6 SO4 3

  Motor (movement of the lateral rectus muscle to move the eyeball laterally).

  Exits cranial cavity via the: Superior orbital fissure

  
• CN7 (VII) FACIAL

  Motor (to M.O.F.E, posterior belly of digastric, stylohyoid and stapedius muscles)

  Sensory (taste sensation to anterior 2/3rds of the tongue, and general sensation to a small area of skin in front of the ear)

  Parasympathetic(secretion of tears and saliva)

  Exits cranial cavity via the: Internal acoustic meatus then the stylomastoid foramen

  
• CN7 (VII) FACIAL

  Exits cranial cavity via the: Internal acoustic meatus then the stylomastoid foramen

  Stylomastoid foramen

  (A hole located between the styloid process and mastoid process of the skull)

  
• CN7 (VII) FACIAL

  greater petrosal nerve: Travels to lacrimal gland above the eye to produce tears

  
• CN7 (VII) FACIAL

  nerve to stapedius: Travels to innervate the stapedius muscle moving the stapes bone in the middle ear

  
• CN7 (VII) FACIAL

  chorda tympani: Provides parasympathetic secretomotor supply to the sublingual and submandibular gland to produce saliva.

  Also transmits taste sensation from the anterior 2/3rds of the tongue.

  
• CN7 (VII) FACIAL

  A) greater petrosal nerve

  B) stapedius

  C) chorda tympani

  D) posterior auricular nerve

  E) digastric

  F) stylohoid

  
• CN7 (VII) FACIAL

  Facial nerve exists cranial cavity through stylomastoid foramen, runs onto the face passing through the parotid gland(does not innervate) and its 5 branches spread on to the face to supply motor innervation to the MOFE.

  
• CN7 (VII) FACIAL

  5 branches spread on to the face to supply motor innervation to the MOFE.

  1)Temporal

  2)Zygomatic

  3)Buccal

  4)Marginal mandibular

  5)Cervical

  
• Temporal Branches of facial nerve

  Innervate the frontalis, orbicularis oculi and corrugator supercilli

  
• Zygomatic Branches of facial nerve

  Innervate the orbicularis oculi