Cranial nerves Flashcards
What nerve is at risk during excision of a submandibular salivary gland?
Mandibular branch of facial nerve
Lingual nerve
Hypoglossal nerve
What structures are contained in the cavernous sinus?
Occulomotor nerve Trochlear nerve Abducens nerve Ophthalmic nerve Maxillary nerve Internal carotid
Name all 12 cranial nerves?
1-olfactory 2-optic 3-occulomotor 4-trochlear 5-trigeminal 6-abducens 7-facial 8-vetibulocochlear 9-glossopharyngeal 10-vagus 11-accessory 12- hypoglossal
After a superficial parotidectomy the patient reports cheek going red and sweating, what nerve has been damaged?
Auriculotemporal branch of trigeminal nerve
What nerve carries parasympathetic innervation to submandibular salivary gland proximal to tongue?
Chorda tympani carried by lingual nerve
What muscles does the facial nerve supply?
Muscles of facial expression
Posterior belly of digastric
Stylohyoid and stapedius muscles
A patient has a head injury and damages foramen rotundum at base of skull- what nerve is damaged?
Maxillary division of trigeminal nerve
What nerve would be damaged if the foramen ovale was affected?
Mandibular division of trigeminal nerve
And Optic ganglion
What is supplied by the mandibular branch of the trigeminal nerve?
Motor component to muscles of mastication, mylohyoid, anterior belly of digastric, tensor veil palate I and tensor tympani
Sensory innervation to the mandibular dentition.
What nerves supply the digastric muscle?
Posterior belly supplied by facial nerve.
Anterior belly supplied by trigeminal nerve vis the mylohyoid nerve
What muscle is supplied by the abducens nerve?
Lateral rectus
What vessel is associated with trigeminal neuralgia?
Superior cerebellar artery
After an IDB patient complains of a watery eye and difficulty blinking, what nerve is affected?
Zygomatic branch of facial nerve.
What structures are derived from the 4th pharyngeal arch?
Pharyngeal constrictors, levator veli palatini, cricothyroid, larynx and vagus nerve
What is the function of the olfactory nerve?
Special sensory supply for smell and advanced aspects of taste
What is the function of the optic nerve?
Special sensory information for vision and pupil responses
What is the function of the occulomotor nerve?
Motor innervation to extra occlular muscles
Parasympathetic supplied the sphincter papillae for constrict the pupil.
Sympathetic fibres help raise eyelid.
What is the function of the trochlear nerve?
Purely somatic function of the superior oblique muscle which depresses the eyeball
What is the function of the trigeminal nerve?
Sensation over face, oral mucosa, conjunctiva, tympanic membrane and sinuses.
Supplies corneal reflex, jaw jerk and taste sensation.
Motor division supplies MoM.
Sensation fibres to anterior 2/3rd of tongue and secretomotor supply to submandibular and sublingual and lacrimal glands
What are the branches of the trigeminal nerve?
Ophthalmic branch sensory from the superior orbital fissure.
Maxillary branch sensory from the foramen rotundum
Mandibular branch motor and sensory from foramen ovale.
What is the function of the abducens nerve?
Somatic motor function to lateral rectus muscle allowing the eyeball to abduct
What is the function of the facial nerve?
Somatic motor supply to muscles of facial expression.
Taste sensation for anterior 2/3rd of tongue via chorda tympani
Branches to stapedius muscles of middle ear.
What is the function of the vestibulocochlear nerve?
Sensory function controlling hearing and balance
What is the function of the glossopharyngeal nerve?
Sensory to posterior 1/3rd of tongue and pharynx
Taste to posterior 1/3rd of tongue
Motor supply to stylopharyngeus.
What is the function of the vagus nerve?
Wide parasympathetic distribution to viscera of upper abdomen.
Motor supply to soft palate, pharyngeal and laryngeal muscles.
What is the function of the accessory nerve?
Motor supply to trapezius and sternomastoid muscles
What is the function of the hypoglossal nerve?
Motor supply to muscles of the tongue allowing for protrusion
What are the potential extra cranial causes of facial sensory loss?
Trauma Inflammatory - osteomyelitis Neoplastic carcinoma of antrum or nasopharynx Metastatic tumours Leukaemia
What are the potential intra cranial causes of facial sensory loss?
Trauma Inflammatory MS, sarcoidosis Neoplastic cerebral tumours Vascular disease Paget’s Medications
What is Bell’s palsy?
It is the most common acute LMN lesion caused by inflammation of the facial nerve which may be associated with infection most commonly HSV leading to demyelination and oedema usually in he stylomastoid canal.
How is Bell’s palsy managed?
Systemic corticosteroids 20mg 4x daily for 5 days then reduce for following 4 days.
Eye patch to protect cornea and eye drops for dryness.
A patient suffers damage to accessory nerve, which muscle would you use to assess the damage?
Trapezius muscle - shrugging shoulders
You are planning on restoring an upper right 1st molar, which nerve will your local anaesthetic aim to anaesthetise?
Superior posterior alveolar nerve
- supplies sensory inner action to molar teeth, gingivae and periosteum.
