Peripheral distribution of Cranial Nerves I and II Flashcards
1
Q
what is the olfactory nerve involved in
A
involved in sensory of cell
2
Q
what are the fibres of the olfactory nerve
A
- special sensory afferents ( it is purely sensory)
3
Q
where does the olfactory nerve travel
A
- first order neurones are in the nasal cavity and they trap the odour molecules, then go through the cribriform plate of the ethmoid bulb and into the olfactory tract
4
Q
what is the optic nerve involved in
A
vision
5
Q
what fibres does the optic nerve have in it
A
special sensory fibre
- it is purely sensory
6
Q
describe the pathway of the optic nerve
A
- extends out of the cerebrum
- made up of the axon of the ganglion retinal cells that receive input from the photoreceptor cells
- they feed into the optic nerve
- the two optic nerves come together at the optic chiasma
- they then cross over and go into the optic tract
- this goes to the lateral deiculum ganglia and to the visual cortex
7
Q
what are the photoreceptor cells
A
rods and cones
8
Q
what do cones do
A
- colour vision rods
9
Q
what do rods do
A
- low light vision
10
Q
what are the nerves that move the eyeball
A
- Oculomotor (CNIII), Trochlear (CNIV), & Abducens (CNVI)
11
Q
how man extraocular muscles are there
A
- 6 extraocular muscles that move the eye and a 7th muscle that controls the upper eyelid
12
Q
what are the 6 extraoclular muscles
A
- superior rectus
- medial rectus
- lateral rectus
- inferior rectus
- superior oblique
- inferior oblique
13
Q
where do the rectus muscles attach
A
- they have a common origin of the annulus of Zinn and all attach to the sclera of the eyeball
14
Q
what innervates the four rectus muscles
A
- superior rectus - - Oculomotor (CNIII)
- medial rectus - Oculomotor (CNIII),
- lateral rectus - abducens (CNVI)
- inferior rectus - Oculomotor (CNIII),
15
Q
what does the superior oblique muscle attach to
A
attaches posterior to the sphenoid bone, it then courses media and goes through the trochlea of the frontal bone this inserts on the eyeball just inferior to the superior rectus muscle on the sclera
16
Q
what innervates the superior oblique muscle
A
Trochlear (CNIV)
17
Q
what does the inferior oblique muscle attaches to
A
its origin is the maxilla bone, it then attaches to the sclera posterior to the lateral rectus
18
Q
what is the inferior oblique muscle innervated by
A
- Oculomotor (CNIII)
19
Q
what attaches to the annulus of Zinn
A
- the 4 rectus muscles are attached onto this ring
20
Q
What is the annulus of Zinn
A
- tendinous ring
- it divides up the superior orbital fissure into two spaces
21
Q
what movements does - superior rectus - inferior rectus - medial rectus - lateral rectus - superior oblique - inferior oblique do?
A
superior rectus – elevation adducts and internally rotates (main movement is elevation )
inferior rectus – depression adduction and externally rotates (main movement is elevation)
medial rectus – adduction
lateral recuts – abduction
superior oblique – depresses, abducts, and internally rotates (main action is depression)
inferior oblique – elevates, abducts and externally rotates (depress the eye main movement)
22
Q
what is abduction in terms of eye movement
A
– away from the midline – eye moves laterally
23
Q
what is adduction in terms of eye movement
A
– towards the midline eye moves medially
24
Q
what are the fibres of the oculomotor nerve
A
- general somatic efferent – voluntary control (SOMATIC – IN CONTROL)
- general visceral efferent – this is out of our control ( VISCERAL – OUT OF CONTROL)
25
what is the muscle that causes the eyelid to move
Levator palpebrae
26
what does the oculomotor nerve innervate
- superior, medial and inferior rectus and Levator palpebrae – parts that we can control
- ciliary ganglion which goes to the sphincter pupillae and ciliary muscle – the ciliary ganglion is a parasympathetic ganglion this is involuntary
27
what fibres pass through the ciliary ganglion
- presynaptic parasympathetic fibres that travel to the cillary ganglion
- the sympathetic fibres passing through ciliary ganglion from the internal carotid plexus these innervate dilator papillae and the blood vessels of the eyes
28
what are the fibres of the Trochlear Nerve CNIV
- general somatic efferent GRE
| - it is in the upper part of the superior orbital fissure
29
what does the trochlear nerve innervate
- superior oblique muscle
30
what are the fibres of the Abducens (CNVI)
- general somatic efferent
| - it passes through the annulus of Zinn in the central region of the superior orbital fissure
31
what does the abducens (CNVI) innervate
lateral rectus muscle
32
the axis does not...
follow the pyramidal shape of the orbit therefore it needs to be aligned, the eye needs to move so that the gaze of the orbit sits across the muscle
33
How do you isolate and test superior and inferior rectus
- need to align the axis of the eye with the vector pull of the muscle
- therefore we need to abduct the eye this the axis of the eye runs over the vector pull of the muscle therefore you are in alignment then we can just test for elevation therefore you are just testing superior rectus
- to test inferior rectus abduct the eye and test depression
34
How do you isolate and test inferior and superior oblique
- the vector pool is not aligned with the axis of the eye
- need to move the eyeball so it is aligned
- therefore adduct the eye to test these muscles
- isolate inferior and superior oblique
- they we can test superior oblique for elevation and inferior oblique for depression
35
How do you isolate and test the medial and lateral rectus
- medial and lateral rectus – get patient to look medially and laterally – abduction and adduction – they only have one movement easy to isolate
36
what is oculomotor nerve palsy
- this is relating the movement of the eye and what would go wrong if the nerve had a lesion on it
37
what are the symptoms of oculomotor nerve palsy
- Ptosis (Levator palpabrae superioris) – get a droopy eye lid
- Stabismus (eyes not alligned)
- Dyplopia (double vision)
- Dilated pupil
- Down and out – unopposed “down” of superior oblique and “out” of lateral rectus
38
what can cause oculomotor nerve palsy
- Head injury, infection, migraine, brain tumour, aneurysm, diabetes, or high BP
39
what are the symptoms of trochlear nerve palsy
- paralysis of superior oblique – depression, abduction and intorsion
- patients attempt to minimise diplopia by tiling head
- diplopia – double vision, axis of the eye, ptient will tilt there head to minimise diplopia by tilting head
40
what is the nerve palsy that is hardest to diagnose and rarest
Trochlear
41
what are the symptoms of abducens Nerve palsy
- paralysis of lateral rectus
- effected eye cannot abduct
- a long course through the cavernous sinus – abducens palsy can be a sing of raised intracranial pressure
42
what are the fibres of the Trigenimal nerve
- general somatic afferent GSA – sensory vontrol
- branciomotr effernet – BE1 – has development in the branchio – it comes from the 1st pharygenal arch compared to myotomes
43
what are the 3 branches of the trigeminal Nerve
- V1 ophthalmic nerve (GSA) – sensory only
- V2 maxillary nerve (GSA) – sensory only
- V3 mandibular nerve (GSA, BE) – mixed nerve
44
what is the mixed nerve branch of the trigeminal nerve
- V3 mandibular nerve (GSA, BE) – mixed nerve
45
what is the sensory innervation of the trigeminal nerve to the face
- Skin, Mucous membrane of nasal cavity, Mucous membrane of oral cavity
- Anterior 2/3 tongue, Upper and lower dentition, Paranasal sinuses
46
what are the motor innervation of the trigeminal nerve to the face
- msucles of mastication and other muscles of the 1st pharyngela arch
47
post ganglionic neurones of parasympathetic ganglia....
travel with branches of trigeminal nerve
48
what are the 3 branches of the V1 ophthalmic nerve
Lacriminal
frontal
nasocillary
49
describe the 3 branches of the V1 ophthalmic nerve and what they supply
- lacrimal – piereces through the gland is the gland is parasympathetic, it supplies sensory input to the upper eye lid and conjutiva of the eye
- frontal – divides into = supratrochlear and superorbital
- nasociliary – the main function is the cornea, it gives a sensory supply to the cornea
50
How many branches are there of V2 Maxillary
there are 14 differnet branches
51
what are some of the divisions of V2 maxillary
infraorbital
superior alveolar branches – to upper teeth
palatine
zygomatic
52
what does V3 innervate
muscles of mastication
ant belly digastric/mylohyoid
tensor tympani – msucel that tenses the tympahni membrane within the ear
tensor veli palatini
```
Sensory
buccal (mucous membrane of cheek)
auriculotemporal
inferior alveolar
lingual
```
53
there is no dermatome for region....
C1
54
what happens if there is damage to trigeminal nerve
• Pressure aneurysm, tumour infiltration (rarely injury)
– Paralysis muscles of mastication
– Loss of sensation to face
– Loss of corneal reflex
– A 3rd molar extraction can damage lingual nerve – loss of sensation to anterior tongue (taste and somatosensory) and reduced salivation due to involvement of the lingual nerve
