8.1 Cranial Nerves III, V and VII Flashcards
Where does the oculomotor nerve originate from?
Anterior midbrain
Which two arteries does the oculomotor nerve pass through as it leaves the brain?
Inferior to cerebral artery
Superior to superior cerebellar artery
Which layer does the oculomotor nerve pierce to enter the cavernous sinus?
Dura mata
Via which fossa does the oculomotor nerve exit the cranial fossa?
Superior orbital fissure
Name the 2 structures that the superior branch of the oculomotor nerve innervates
Superior rectus muscle
Levator palpabrae superioris muscle
Sympathetic- superior tarsal muscle
Name the 2 structures that the inferior branch of the oculomotor nerve innervates
Inferior rectus
Medial rectus
Inferior oblique
Parasympathetic- sphincter pupillae + ciliary muscles
Where does the trigeminal nerve originate from?
3 sensory nuclei and 1 motor nucleus from the midbrain to the medulla
Where does the sensory root of the trigeminal nerve form?
At the level of the Pons
When does the sensory root become the trigeminal ganglion?
Middle cranial fossa, lateral to the cavernous sinus
To which branch of the trigeminal nerve is the motor root distributed to?
V3- mandibular nerve
Name the 3 branches of the trigeminal nerve
V1- opthalmic
V2- maxillary
V3- mandibular
Where does the ophthalmic nerve exit the cranial cavity?
Superior orbital fissure
Where does the maxillary nerve exit the cranial cavity?
Foramen rotundum
Where does the mandibular nerve exit the cranial cavity?
Foramen ovale –> Infra-temporal fossa
What are the 3 branches of the ophthalmic nerve?
Frontal
Lacrimal
Nasocilary
Which area of the face does V1 innervate?
Skin and mucous membranes of scalp, forehead, dorsum of nose, cornea, upper eyelid, conjunctiva, frontal and ethmoidal sinuses
Which area of the face does V2 innervate?
Skin and mucous membranes of fronto-nasal prominence derivatives
Lower eyelid, conjunctiva, cheeks, maxillary sinus, nasal cavity, upper lip, superior palate, upper molars, incisors and canines
Which area of the face does V3 give sensory innervation to?
Skin, mucous membranes and striated muscle derivatives of the mandibular prominence:
Floor of oral cavity, external ear, lower lip, chin, anterior 2/3rds tongue, lower molar, incisor and canines
Which area of the face does V3 give motor innervation to?
Muscles of mastication, anterior belly of digastric, mylohyoid, tensor veli palatini, tensor tympani
Which structures do the parasympathetic fibres which run with the trigeminal nerve innervate?
Submandibular and sublingual glands
Parotid gland
Lacrimal gland
Mucous glands in nasal cavity
Where does the facial nerve originate from?
Large motor root in the Pons and a small sensory root
Which fossa do the roots of the facial nerve travel through as they leave the Pons?
Internal acoustic meatus in the temporal bone
Where do the roots fuse?
Facial canal
What is the name of the ganglion that the facial nerve forms?
Geniculate ganglion
Name the 3 nerves which the facial nerve gives off after the geniculate ganglion
Greater Petrosal Nerve
Nerve to stapedius
Chorda tympani
What does the facial nerve go through to exit the facial canal?
Stylomastoid foramen
Which nerves branch from the facial nerve when it is extracranial?
Posterior auricular
Nerve to digastric
Nerve to stylohyoid
Where does the motor root of the facial nerve split into branches?
Parotid gland
Name the 5 motor branches of the facial nerve
Temporal Zygomatic Buccal Marginal Mandibular Cervical
What do the motor nerve branches of the facial nerve innervate?
Muscles of facial expression- derivatibes of the 2nd pharyngeal arch
What special sensory innervation is the chorda tympani responsible for?
Taste sensation in anterior 2/3rds of tongue
What is the corneal reflex?
Involuntary blinking of the eyelids stimulated by tactile, thermal or painful stimulation of the cornea.
What is the afferent limb of the corneal reflex?
Opthalmic nerve (V1)
What is the efferent limb of the corneal reflex?
Facial nerve
Describe how a oculomotor nerve lesion will present
Ptosis
Down and out eyeball
Dilated pupil
Describe how a trigeminal nerve lesion will present
Cannot look laterally
Describe how an intercranial facial nerve lesion will present
Facial muscles of expression paralysed
Reduced salivation and loss of taste sensation
Hypersensitive to sound
Reduced lacrimal fluid production
Describe how an extracranial facial nerve lesion will present
Paralysis or weakening of the muscles of facial expression ONLY
