Week 5 Flashcards
What is the crista galli
bony projection which attaches to falx cerebri, front of middle cranial fossa
what is the falx cerebri
large fold of dura mater in the midline of the head, very tough layer of dense irregular connective tissue.
Separates right and left hemispheres
what is the tentorium cerebelli
fold of dura mater which covers cerebellum, almost horizontal fold. Separates back of cerebral hemispheres with the cerebellum underneath
what do the large folds of dura mater and CSF allow
protects the brain by minimising movement
what is the vessel which is in an endotheium lined channel in the attachment of the falx
superior sagittal sinus
what are the walls of the superior sagittal sinus made of
dura
what veins drain the upper part of the brain
superior cerebral veins
do the superior cerebral veins have valves
no
if the superior cerebral veins tear, what haemorrhage do they cause
subdural haemorrhage
what does the great cerebral vein drain
the midline part of the forbrain (area of thalamus and hypothalamus
where does the great cerebral vein pass into
where the falx meets the tentorium
if a patient can’t see out of half of both of their eyes what does this indicate
the problem must be before the optic chiasm
what could cause a lesion at the optic chiasm which would result in only half of your vision on both eyes
e.g. pituitary adenoma
if a patient can’t turn their eye medially and the eyelid can’t stay open what could this indicate
occulomotor nerve problem
what muscle turns the eye medially
medial rectus
if a child can’t look straight with one eye what could this be
not necessarily a cranial nerve problem, lazy eye is common in childhood
what is a dermatome
an area of skin supplied by any particular spinal or cranial nerve
how many dermatomes does the trigeminal nerve have
3
if you have crusty looking lesions over a particular dermatome what is this called
shingles
what virus causes shingles
varicella zoster
how does varicella zoster cause shingles
after having chicken pox the virus stays in the trigeminal ganglion and causes shingles by coming down one of the divisions to the face
what is particularly concerning about shingles to the opthalmic division
that the cornea could become scarred
what is the treatment following a facial palsy caused by local anaesthetic in the lower jaw
close and cover eye with pad until anaesthetic wears off
reassure patient
do a couple of checks to make sure not stroke (other parts of the body normally affected with a stroke)
if someone has problems speaking, eating and controlling dentures what nerves/muscles area are affected
- marginal mandibular branch
- buccal branches
- buccinator
what nerve supplies sensory sensation to the inside of the larynx including vocal chords
vagus nerve
if someone has:
- not squinting
- constricted pupil
- ptosis (drooping eyelid)
- not sweating on one side of face
what might this mean
damage to the sympathetic trunk
e.g. horners syndrome
can be congenital or aquired from tumour
Describe the olfactory nerves
- sensorineural cells whose fibres end in the upper part of the nasal cavity
- synapse with neurons in the olfactory bulb
- nerves too small to see but bulb and tract are visible
describe the optic nerve
- fibres cross over e.g. from right eye to left side of brain
- converge at optic chiasm
- from the optic chaism axons continue back, and some of the pss through the lateral geniculate body to the superior colliculus
- the rest become optic radiation
What do the 3rd,4th and 6th cranial nerves do
work together to produce all movements of the eye
describe the oculomotor nerve
- originates on medial side of the cerebral peduncles
- splits into 2
- goes through superior orbital fissure
- innervates most of the external eye muscles through the ciliary ganglion and all of the intrinsic eye muscles
describe the trochlear nerve
- emerges dorsally from the brainstem
- goes through the superior orbital fissure
- innervates only the superior oblique muscle
describe the abducens nerve
- emerges just below the pons
- goes through the superior orbital fissure
- innervates only the lateral rectus which abducts the eye
describe the trigeminal nerve
- sensation to the entire face and forehead
- innervates muscles of mastication
- opthalmic provides sensation for the nose and forehead
- maxillary provides sensation to the cheeks nd upper lip
- mandibular provides sensation to the lower lip, jaw and anterior to the ear
- ganglion is in meckel’s cave (invagination of the dura mater)
describe the facial nerve
- supplies all the muscles of facial expression and taste sensation from anterior 2/3 of the tongue
- emerge just inferior to the pons
describe the vestibulocochlear nerve
- two nerves tightly bound together
- sensation of balance and hearing
- emerge just inferior to the pons and lateral to where abducens begins
describe the glossopharyngeal nerve
- relates closely with 10th and 11th CN
- sensory to posterior 1/3 of tongue and general sensation to whole of pharynx
describe the vagus nerve
- relates closely with 9th and 11th CN
- parasympathetic innervation for a huge portion of the body as far as the splenic flexure of the colon
- muscles of pharynx and larynx
describe the accessory nerve
- relates closely with CN 9 and 10
- has 2 parts (spinal and cranial portions)
- cranial follows the vagus nerve and performs similar functions
- spinal accessory innervates the trapezius and sternocleidomastoid muscles
describe the hypoglossal nerve
- originates as a number of small rootlets near the midline from the medulla oblongata
- goes through a channel in the occipital bone just above the foramen magnum
- controls intrinsic and extrinsic muscles of the tongue
