Anatomy Flashcards
(162 cards)
1
Q
Label the following diagram showing the bones and features of the bony orbit
A
- Orbital plate of frontal bone
- Optic canal
- superior orbital fissue
- Sphenoid bone
- zygomatic bone
- infraorbital foramen
- maxilla
- orbital plate of ethmoid bone
- Lacrimal bone
- nasal bone
- supraorbital notch / foramen
2
Q
What is the shape of the bony orbit
A
pyramidal shape
3
Q
What is at the apex of the bony orbit?
A
optic canal
4
Q
What helps to protect the eye from a direct blow?
A
the superior and inferior orbital margin
5
Q
What is most vulnerable during an orbital blowout fracture?
A
The medial wall and orbital floor - extremely thin
6
Q
What is the main external muscle of the eyelids?
A
obicularis oculi
7
Q
Label the following diagram of obicularis oculi
A
- Orbital part
- Palpebral part
8
Q
Label the following diagram of the ligaments of the eye
A
- Lateral palpebral ligament
- Orbital septum
- inferior tarsus
- medial palperbral ligament
- superior tarsus
- tendon of levator palpebral
9
Q
What is the orbital septum?
A
A sheet of fascia
10
Q
What are the tarsal glands and what do the secrete?
A
They are modified sebaceous glansa embedded in the tarsi - they are involved in lipid secretion
11
Q
Label the following diagram of the surface anatomy of the eye
A
- The location of the lacrimal gland
- The limbus - corneoscleral junction
- White sclera covered by conjuctiva
- The conjuctival fornix
- Lower eyelid lined by conjunctiva
- inferior lacrimal papilla and punctum
- lacrimal lake
- a conjuctival vessel
- iris - covered by cornea
12
Q
Which nerve is responsile for the parasympathetc production of lacrimal fluid?
A
CN VII
13
Q
What are the 3 layers of the eye?
A
Fibrous layer
Vascular layer
Photosensitive layer
(from outer to inner)
14
Q
What makes up the fibrous outer layer of the eye?
A
sclera - muscle attachment
Cornea
15
Q
Label the following diagram of the fibrous part of the eye
A
- Sclera
- Cornea
16
Q
What 3 components make up the vascular layer (uvea) of the eye?
A
Iris - pupil diameter
Ciliary body - controls iris, shape of lens and secretion of aqueous humour
Choroid - nutrition and gas exchange
17
Q
Label the following diagram of the uvea (vascular layer)
A
- Ciliary body
- Iris
- choroid
18
Q
What is the photosensitive layer of the eye?
A
The retina
19
Q
Where is the anterior segment of the eye?
A
In front of the lens
20
Q
What are the chambers of the anterior segment? state their boundaries
A
Anterior chamber - between cornea and iris
Posterior chamber - between iris and suspensory ligaments
21
Q
What does the anterior segment contain?
A
aqueous humour
22
Q
Where is the posterior segment and what proportion of the eye is posterior segment?
A
behind the lense
2/3rds of the eye
23
Q
What does the posterior segment of the eye contain?
A
virteous body
24
Q
Label the following diagram of a slit-lamp view of the anterior segment:
A
- A pharmacologically dilated pupil
- The corneal reflection
- The iris
- The location of the iridocorneal angle in the anterior chamber
- The limbus - corneoscleral junction
- Catarct
25
What is the ciliary body made from?
smooth muscle and blood vessels
26
Where does the aqueous circulate and what is its function?
within the posterior chamber - nourishes the lens
27
After the aqueous is secreted from the ciliary body and circulated around the posterior chamber, where does it pass?
passes through the pupil into the anterior chamber and nourishes the cornea
28
Where is the aqueous reabsorbed?
The aqueous is reabsorbed into the scleral venous sinus at the iridocorneal angle
29
What is the iridocorneal angle?
the angle in “open-angle” & “closed-angle” glaucoma
30
What is the fundus of the retina?
posterior area where light is focussed
31
Where is the optic disc found?
In the fundus of the retina
32
Where is the point of CN II formation?
Optic disc
33
Where is the only poin of entry/exit for blood vessels of CN II?
Optic disc
34
What are cone cells (cones)?
photoreceptor cells associated with colour vission
35
Where is the macula located?
In the fundus of the retina
36
What is the macula?
greatest density of cones
37
What is the fovea?
the center of the macula
depression of 1.55mm diameter
area of most acute vission
38
Label the following fundoscopy image of the retina
1. temporal retina
2. nasal retina
3. macula of retina
4. branches of retinal vessels
5. optic disc
6. the central artery of the retina and central vein of the retina
39
What can complete interruption of flow in a retinal artery / vein branch result in?
Loss of an area of visual field corresponding to the area of ischaemia
40
What can complete interruption of flow of the central artery (end artery) or vein result in?
monocular blindness
41
What are the 3 layers of the retina) from posterior to anterior
the photoreceptors
the ganglion cells
axons of the ganglion cells
42
# Fill in the blanks
The axons in the visual pathway maintain specific spatial relationships to each other:
- light from objects in the right visual field is processed by the visual cortex
- light from objects in the lower visual field is processed by the part of the primary visual cortex
The axons in the visual pathway maintain specific spatial relationships to each other:
- light from objects in the right visual field is processed by the **left primary** visual cortex
- light from objects in the lower visual field is processed by the **upper** part of the primary visual cortex
43
Label the following diagram
1. The Ophthalmic artery
2. The internal carotid artery
3. cavernous sinus
4. pituitary gland
5. the optic nerve (CN II)
44
Label the following diagram of arterial blood supply to the eye
1. The internal carotid artery
2. ophthalmic artery
3. ciliary arteries - supply the choroid
4. the central artery of the retina (end artery)
5. nasal cavity branches - contribute to kiesselbach's area
6. forehead (scalp) branches
7. the central vein of the retina - the only vein draining the retina
45
Label the following diagram of venous drainage of the eye
1. cavernous sinus via the superior orbital fissure
2. The optic nerve
3. The superior ophthalmic vein
4. A forehead vein
5. facial vein (orbit drains anteriorly into this vein)
6. inferior opththalmic vein
46
What does this picture highlight and what is significant about it?
the danger triangle of the face
dangerous in bacterial infections as the veins communicate to cavernous sinus
infection can spread from face to brain
47
How many extraocular skeletal muscles are there?
7
48
how many rectus muscles are there and what are there names?
4 rectus muscles:
superior
inferior
medial
lateral
49
where do the rectus muscles originate from?
Where do the insert?
all originate from the common tendinous ring
all insert onto sclera
50
how many oblique muscles are there ?
what are their names?
where do they instert?
2
inferior and superior oblique
insert onto sclera
51
What is the name of the muscle that lifts the upper eyelid?
levator palpebrae superioris
52
Label the following diagram of the extraocular muscles
1. inferior rectus
2. lateral rectus
3. medial recus
4. superior rectus
5. superior oblique
6. optic nerve
7. trochlea
8. levator palpebrae superioris
9. superior tarsus
10. inferior oblique
11. comon tendinous ring
53
Which nerve provides somatic motor innervation of the lateral rectus?
CN VI - abducent nerve
| (LR6)
54
Which nerve provides somatic motor innervation of the superior oblique nerve?
CN IV - trochlear nerve
| (SO4)
55
What nerve provides somatic motor innervation to the extraocular muscles (apart from the lateral rectus and superior oblique)
CN III - oculomotor nerve
56
What is the movement of the eyeball in the verticle axis?
Abduction / Adduction (away and towards midline)
57
How can the eyball move in the transverse axis?
Elevation and depression
58
What is the type of movement of the eyeball in the Anteroposterior axis?
intorsion (medial rotation)
extorsion (lateral rotation)
59
What momvement does lateral rectus cause?
What nerve innervates this muscle?
Abduction of eyeball
CN VI (abducent)
60
what eye movement does superior rectus cause?
What nerve innervates this muscle?
When in abduction superior rectus can only elevate)
CN III (oculomotor nerve)
follow finger laterally and up
61
what eye movement does inferior rectus cause?
What nerve innervates this muscle?
when in abduction inferior rectus can only depress
CN III - oculomotor nerve
62
What eyemovent does medial rectus facilitate?
What nerve innervates this muscle?
can only adduct eyeball
CN III - oculomotor nerve
63
What eye movement does inferior oblique facilitate
what nerve innervates this muscle?
When in adduction inferior oblique can only elevate
CN III - oculomotor nerve
64
what eyemovement is facilitated by superior oblique?
what nerve innervates this muscle?
when in adduction superior oblique can only depress
CN IV - trochlear nerve
65
What muscles are involved in pure elevation of the eyeball?
superior rectus and inferior oblique
66
what muscles are involved in pure depression?
superior oblique and inferior rectus
67
What is the role of the suspensory ligament of the eye?
supports both eyes in the same verticle position within the orbit
68
where does the suspensory ligament attach?
to the zygoma laterally
69
what can damage to the suspensory ligament result in?
diplopia - double vision
70
What is CN V1 and where does it provide general sensory neve supply?
Ophthalmic nerve
the upper eyelid
the cornea
all of the conjunctiva
the skin of the root/bridge/tip of the nose
71
What is CN V2 and where does it supply general sensory nerve supply?
Maxillary nerve
the skin of the lower eyelid
the skin over the maxilla
the skin of the ala of the nose
the skin / mucosa of the upper lip
72
What is CN V3 and where does it provide a general sensory nerve supply?
The mandibular nerve
the skin over the mandible and temperomandibular joint excluding the angle of the mandible
73
Which nerves supply general sensory nerve supply to the angle of the mandible?
C2 and C3 spinal nerves
74
In which direction does a fractured zygoma tend to rotate?
What can this lead to?
rotates medially towards the floor of the orbit
this can damage the infraorbital NVB within the infraorbital canal --\> general sensory deficit of the facial skin
75
How can the blink reflex be clinically tested?
using a sterile point of cotton wool gently touch the cornea
76
Outline the blink reflex
* action potentials are conducted centrally via CN V1 to the trigeminal ganglion
* then in CN V to the pons (afferent [sensory] limb of reflex)
* there are CNS connections between CN V and CN VII
* Action potentials are then conducted periperally in CN VII to the eyelid part of obicularis oculi (efferent [motor] limb of reflex)
77
Outline how sympathetic axons travel from the CNS to the orbit - presynaptic part only
* presynaptic sympathetic axons from the CNS descend in the spinal cord a
* Exit the spinal cord in T1 spinal nerve
* ascend within the sympathetic trunk
* synapse in the superior cervical sympathetic ganglion
78
Outline how sympathetic axons travel from the CNS to the orbit - postsynaptic part only
* From the superior cervical ganglion the post synaptic sympathetic axons enter the internal carotid nerve and external carotid nerve
* They pass onto the surface of the internal and external carotid arteries resepectively
* They are carried to the organs of the head on the surface branches of these arteries
* For the orbit an intracranial branch of the internal carotid artery travels on the ophthalmic artery
79
What do the inferior cervical ganglion and the 1st thoracic ganglia form when they fuse?
stellate ganglion
80
Label the nerves in this posterior view of the pharynx
1. Right and left internal carotid nerves
2. left superior cervical sympathetic ganglion
3. left middle cerrvical sympathetic ganglion
4. left inferior cervical sympathetic ganglion
5. The right vagus nerve
81
Which cranial nerves are involved in the parasympathetic system?
* CN III - oculomotor nerve
* CN VII - facial nerve
* CN IX - glossopharyngeal nerve
* CN X - vagus nerve
82
In the sympathetic nervous system what is the presynaptic neurotransmitter?
acetylcholine
83
In the sympathetic nervous system what is the the postsynaptic neurotransmitter?
noradrenaline
84
In the sympathetic nervous system where is the synapse?
in the sympathetic trunk
85
In the parasympathetic nervous system what is the presynaptic neurotransmitter?
acetylecholine
86
in the parasympathetic nervous system what is the postsynaptic neurotransmitter?
acetylcholine
87
In the parasympathetic nervous system where is the synapse located?
Within the organ
88
Where does the oculomotor nevre (CN III) synapse?
ciliary ganglion in the orbit
89
Which nerve provides parasympathetic innervation to the lacrimal gland? Where does this nerve synapse?
CN VII - facial nerve
synapses in the Pterygopalatine ganglion
90
What nerve provides parasympathetic innervation to the submandibular and sublingual salivary glands?
Where does this nerve synapse?
facial nerve CN VII
synapses in the submandibular ganglion
91
which nerve provides parasymapthetic innervation to the parotid salivary gland?
Where does this nerve synapse?
glossopharyngeal nerve CN IX
synapses in the otic ganglion
92
Which cranial nerve provides sympathetic innervation to the organs of the neck/chest and abdomen (as far as the midgut)?
CN X - the vagus nerve
93
where do the sacral spinal nerves provide parasympathetic innervation?
hindgut, pelvis and perineum
94
what type of innervation does CN III supply?
somatic motor
parasympathetic (autonomic)
95
What muscles does CN III provide somatic motor innervation to?
superior rectus
medial rectus
inferior rectus
inferior oblique
lavator palperbrae superioris
(all extraocular muscle apart from lateral rectus and superior oblique)
96
where does the presynaptic parasympathetic axon of CN III synapse?
ciliary ganglion
97
Where does CN III connect to the CNS?
near the midline at the junction between the midbrain and pons
98
through which foramen does CN III pass?
| (base of skull part of the course)
superior orbital fissure
99
which extraocular muscles does the superior branch of CN III supply?
superior rectus and levator palpebrae superioris
100
Which extraocular muscles do the inferior branch of CN III supply?
Medial rectus
inferior rectus
inferior oblique
(also parasypathetic supply to the ciliary ganglion)
101
State which nerves pass through the ciliary ganglion and state whether or not they synapse.
general sensory fibres from the cornea and conjunctiva - doesn't synapse
postsynaptic sympathetic fibres from the superior cervical ganglion (long cillary nerve) - doesn't synapse here
Inferior branch of CN III - does synapse here
102
What nervous system do the cilliary nerves belong to? what do they control?
autonomic - control diameter of iris and the refractive shape of lens
103
What are the 4 autonomic reflexes of the eye?
Maximal eyelid elevation
pupillary dilation / constriction
focussing the lens
lacrimation
104
what is the vestibulo-ocular reflex?
What CNS connections are involved?
turns the eyes in the opposite direction to a head movement (to stabilise the gaze on an object during head movements)
CNS connections between CN VII and CNs III, IV and VI (extraoccular muscles)
105
What is the oculocardiac reflex?
What CNS connections are involved?
reflex bradycardia in response to tension on the extraocular muscles or pressure on the eye
CNS connections between CN V1 and CN X
106
What are the effects of sympathetic stimulation on the eye?
open eyes wider
get more light into eyes - pupil dilation
focus on far objects
emotional lacrimation
107
What are the effects of the parasympathetic system on the eye?
allow obicularis oculi to work
get less light into eyes (pupil constricts) - protect retina
focus on near objects
reflex lacrimation - wash away stimulant foreign body and clean the cornea
108
What type of muscle is levator palpebrae superioris?
skeletal muscle plus smooth muscle
109
outline how postsynaptic sympathetic fibres reach the levator palpebrae superioris
* the superior cervical sympathetic ganglion
* the internal carotid nerve the internal carotid plexus
* axons carried on the ophthalmic artery…
* and on its branches to the orbital structures
## Footnote
**eyes open wider**
110
What effect does sympathetic stimulation have on the pupil size?
causes dilation
111
What is a non-physiologically enlarged pupil called?
i.e remains large even in bright light
mydriatic pupil
112
What can cause a mydriatic pupil?
drugs, tumour and disease
113
how are the dilator pupillae fibres arranged?
where do they originate?
where do they insert?
radially arranged
originate all around the external circumference of the iris (fixed origin)
insert around the internal circumference of the iris (mobile insertion)
114
What division of the nervous system causes pupillary constriction?
the parasympathetic division
115
What is a non-physiologically constricted pupil called?
i.e still constricted in darkness
mitotic pupil
116
in what syndrome is a mitotic pupil seen?
Horner's syndrome
117
What is a fixed pin-point pupil a sign of
pathological sign of opiate drugs
118
how are the pupillae fibres arranged?
sphincter encircling around the internal circumference of iris
119
What is the light reflex in the stimulated eye called?
the direct light reflex
120
What is the light reflex in the non-stimulated eye called?
the consensual light reflex
121
The special sensory (afferent) limb of the light reflex is carried in the the ipsi/bi/conta lateral CN
ipsilateral CN II (optic nerve)
122
the motor limb of the light reflex is ipsi/bi/contra lateral
via CN?
bilateral
CN III - oculomotor nerves
123
In the light reflex where in the brain do the CNS connections occur?
the thalamus
124
How many neurone chains are involved in the pupillary light reflex?
4
125
What are the 1st neurones in the pupillary light reflex?
* the retinal ganglion cells pass via the ipsilateral optic nerve
* to cross over (decussate) in the optic chiasm
* then synapse in the pretectal nucleus in the midbrain
126
What are the 2nd neurones in the pupillary light reflex?
**bilateral**
* located entirely within the midbrain & connect the pretectal nucleus
* to the next synapse in the Edinger Westphal nucleus (the location of the cell bodies of the parasympathetic axons of CN III)
127
What are the 3rd neurones in the pupillary light reflex?
**bilateral**
pass from the EW nucleus, via CN III then its inferior division, to synapse in the ciliary ganglion
128
What are the 4th neurones in the pupillary light reflex?
**bilateral**
course in the short ciliary nerves to the sphincter pupillae muscles
129
what connects the circumference of the lens and the ciliary body?
what is this structure involved in?
the suspensory ligament of the lens
controlling the refractive shape of the lens
130
what structures are involved in controlling the shape of the lens?
suspensory ligament of the lens
ciliary body and smooth ciliary muscle (like a sphincter around circumference of ciliary body)
131
# choose the correct phrase / word
the ciliary muscle _contracts /relaxes_ in “far vision” (**_no**_ parasympathetics) the ligament _**tightens**_ & the lens _**flattens_** to focus on the distance
the ciliary muscle **_relaxes_** in “far vision” (_no/some_ parasympathetics) the ligament _tightens/relaxes_ & the lens _becomes spherical /flattens_ to focus on the distance
132
# choose the appropriate phrase / word:
the ciliary muscle _contracts /relaxes_ in “near vision” (_no/some_ parasympathetics) the ligament _tightens/relaxes_ & the lens _becomes spherical /flattens_ to focus on near objects (reading)
the ciliary muscle **_contracts_** in “near vision” (**_some_** parasympathetics) the ligament **_relaxes**_ & the lens _**becomes spherical_** to focus on near objects (reading)
133
how do you clinically asses all 3 components of the accommadation reflex?
1. bilateral pupillary constriction (CNs III)
2. bilateral convergence - medial rotation of both eyes (CNs III)
3. bilateral relaxation of the lens
the lens becomes spherical due to contraction of the ciliary muscles (CNs III)
134
What causes a raised intracranial pressure?
an increased pressue in fluid surrounding the brain or an increase in pressure within the brain itself:
brain tumour / head injury / hydrocephalus / meningitis / stroke
135
There are 3 main compenents that contribut to the intracranial volume, what are they?
brain, blood and CSF
136
why can't the cranial cavity cope with an increase in intracranial volume?
it is an eclosed space that is not flexible or elastic
137
what proportion of pateints with a raised ICP will report with visual problems?
65-75%
138
What are some common visiual problems people with a raised ICP report with?
transient blurred vision
double vision - diplopia
loss of vision
papilloedema
pupillary changes
139
What is the optic nerve (CN II) covered by?
meninges:
dura matter
arachnoid matter
Pia matter
140
what is the space between the arachnoid and pia called?
What is this space filled with?
sub- arachnoid space
filled with cerebrospinal fluid (CSF)
141
What are the meninges?
protective coverings of the brain and spinal cord
142
how many layers of dura mater are there and what do they enclose?
2 layers that enclose the dural venous sinuses
143
which is nerve provides the sensory supply to the dura mater?
CN V - trigeminal nerve
144
where is the subarachnoid space found?
between arachnoid mater and pia mater:
completely surrounds both the brain and the spinal cord
(continuous)
145
what is the function of the subarachnoid space?
contains CSF which cushions and protects
146
how much CSF is produced / day?
400-500 ml/day
147
Where is the CSF produced?
in the choroid plexus of the ventricles
148
Where is the CSF reabsorbed?
into the dural venous sinus via the arachnoid granulations
149
Where can CSF be sampled?
via lumbar puncture at L3/4 or L4/5 IV disc levels
150
What appearance should CSF have?
should be clear
151
Label the following diagram of the brain ventricles and other important structures:
1. The 3rd ventricle
2. Left lateral ventricle
3. Right lateral ventricle
4. The subarachnoid space
5. Central canal
6. The 4th ventricle
7. The cerebral aquaduct
8. th pituitary gland
9. The optic chiasm
10. The superior sagittal sinus
152
Outline the circularion of CSF :
1. secreted by the choroid plexus (modified pia locared in the lateral and 3rd ventricles)
2. through the cerenral aquaduct into the 4th ventricle
3. into the subarachnoid space( and some into the the central canal)
4. reabsorbed from the subarachnoid space via the arachnoid granulations
5. Into the dural venous sinuses
153
where would a raised ICP be transmitted?
along the subarachnoid space in the optic nerve sheath
154
How does a raised ICP affect the optic nerve, central artery and vein of the retina?
compresses them - can lead to bulging or swollen optic discs (papilloedema)
155
what type of damage is CN III (oculomotor nerve) susceptible in a raised ICP?
compression / tentortial herniation
156
What can damge to CN III result in?
paralysis of somatic motor innervation
paralysis of parasympathetic innervation of the sphincter of the pupil
157
if you ask someone to look straight ahead and they do this, which nerve is damaged?
Oculomotor nerve - supples all extraocular muscles apart from lateral rectus and superior oblique
158
How can the trochlear nerve be damaged by a raised ICP?
stretching / compression
159
what can damage to the trochlear nerve (CN IV) result in?
paralysis of the superior oblique muscle
inferior oblique muscle is unopposed so eye can not move inferomedially
160
If you ask a patient to gaze to the right and they look like this what nerve is damaged?
What visual symptom might this pateint experience?
damage to the trochlear nerve ( CN IV)
diplopia when looking down
161
how can a raised ICP damage the abducent nerve ( CN VI)?
stretching
162
what can damage to the the abducent nerve cause? How will this clinically present?
paralysis of the lateral rectus muscle
eye cannot move laterally in the horizontal plane
medial deviation of the eye
