Cranial nerves Flashcards
How many extraoccular muscles are there? name them and the nerves which innovate them
6 4 rectus muscles superior, medial, inferior (oculomotor) Lateral (abducens) 2 oblique muscles Superior (trochlear) Inferior (oculomotor)
What is the origin and attachment of the rectus muscles?
Origin- common tendinouse ring
Attachment- sclera
Where do the oblique muscles attach?
Behind the equator
What does the suprior oblique muscle hook around?
fibrocartilaginous pulley (trochlear)
What is the action of the superior and inferior oblique muscle?
Superior- Down and intorsion (inward rotation)
Inferior- up and extorsion (outward rotation)
What Is the parasympathetic nervous pathway of the oculormotor nerve?
Pre-synaptic fibers travel to the ciliary ganglion
Post-synaptic fibers innervate the sphincter pupillae and ciliary muscles
What is the sympathetic innervation to the eye?
Sympathetic fibres go from the carotid plexus to the dilator pupillae blood vessels of the eye
What is the primary action of the medial, lateral, inferior and superior rectus muscles?
Medial- adduction
lateral- abduction
Superior- elevate
inferior- depress
What are the symptoms of an oculomotor palsy?
ptosis (lev palpebrae) Stabismus (eyes not aligned) Dyplopia (double vision) Dilated pupil Down and out due to the unapposed action of superior oblique (down) out (lateral rectus)
What cause cause an oculomotor palsy?
Ischemic event from diabetes and hypertension
aneurysm at the junction of internal carotid and posterior communicating arteries
What are the is the cause and symptoms of a trochela pasly?
Paralysis of superior oblique
Hardest to diagnose but also rarest.
Patients attempt to minimise diplopia by tilting head away from paralyzed eye
Eyes move up and in
What is the cause and symptoms of an abducens pasly?
Paralysis of lateral rectus
Effected eye cannot abduct
Goes through cavernous sinus – abducens palsy can be a sign of raised intracranial pressure
What is the name of the intermediate facial nerve? What are the categories of its function?
nervus intermedius– special sensory, and parasympathetic
What are the muscles of facial expression?
post belly digastric, stylohyoid, stapedius
What is bells palsy? What is the potential cause?
Facial muscle paralysis LMN injury
swelling of nerve in facial canal
Explain the concept of for-head sparing
a patient with forehead sparing (i.e. no involvement to the occipitofrontalis muscle) will have a UMN origin to the palsy, due to the bilateral innervation of the forehead muscle).
UMN- stroke
LMN- bells palsy-forhead will crease
What are the symptoms of bells palsy? State the inhibited branch of the facial nerve causing each symptom
Droopy eye lid (can not close eyes), (temporal and zygomatic branches)
Facial paralysis
Hyperacusis (increased sensitivity to sound) (nerve to stapedius)
Metallic taste (chorda tympani)
Reduced lacrimation (greater petrosal nerve)
Droopy corner of the mouth
dry mouth
What are the branches of the vagus nerve in the neck?
Auricular nerve
external acoustic meatus and tympanic membrane
Pharyngeal nerves – pharyngeal plexus
muscles and mucous membranes
Superior laryngeal nerve –
sensory to laryngeal mucosa above vocal folds, motor to cricothyroideus
Right recurrent laryngeal nerve – loops under RSCA
sensory to mucosa below folds, motor to all intrinsic laryngeal muscles (excluding cricothyroideus)
Left recurrent larnygeal – loops under the aortic arch
What is the parasympathetic innervation to the intrinsic eye muscles?
Ocularmotor nerve, ciliary ganglion, opthalmic branch of trigeminal
What is the parasympathetic innervation to the lacrimal gland, nasal cavity, maxillary sinus ans palate?
Facial nerve
Pterygopalatine ganglion branch
maxillary trigeminal
What is the parasympathetic innervation to the submandibular and sublingual glands?
facial nerve
Submandibular ganglion
mandibular trigeminal
What is the parasympathetic innervation to the parotid gland?
glosso nerve
otic ganglion
mandibular trigeminal
List the nerves found in the …
3, 4, 5, 6
What is the consequnce of damage to the olfactory nerve?
Anosmia
