Head: Orbit Flashcards
1
Q
Bones of the BASE of the Orbit
A
- Orbital margin (orbital opening)
2
Q
Bones of the APEX of the Orbit
A
- At the optic canal (lesser wing of sphenoid)
3
Q
Bones of the SUPERIOR part of the Orbit
A
- Orbital part of frontal bone
4
Q
MEDIAL bones of the Orbit
A
- Orbital plate of ethmoid
- Lacrimal
- Frontal process of maxilla
- Lacrimal groove
- Fossa
5
Q
INFERIOR bones of the Orbit
A
- Zygomatic
- Maxilla
6
Q
LATERAL bones of the Orbit
A
- Frontal process of zygomatic bone
- Greater wing of sphenoid
7
Q
Preorbita
A
- Periosteum that lines the orbit
8
Q
Orbit and Orbital region content
A
- Obicularis oculi
- Eyelids
- Lacrimal apparatus
- Eyeball
- Extraocular muscles and their innervation
- Optic nerve
- Ophthalmic nerve (V1) branches
- Opthlamic veins
- Ciliary ganglion
- Retrobulbar fat
9
Q
Eyelids (protect the eye)
A
- Skin on the outside
- Conjunctiva lines the inside
10
Q
Content of the eyelids
A
- Orbicularis oculi, palpebral part (CN VII)
- Tarsal plate (tarsus)
11
Q
Eyelid is the insertion of
A
- Levator palpebrae superioris (CN III innervation)
- Superior tarsal muscle (sympathetic innervation) onto the upper eyelid
12
Q
A ptosis can result from
A
- Lesion of oculomotor nerve or sympathetics to the head
13
Q
Cornea
A
- Transparent layer that covers iris and pupil
- Avascular
- Continuous with sclera (white of the eye)
14
Q
Corneal reflex
A
- Touching elicits blink response
15
Q
Sensory innervation of upper eyelid and cornea
A
- Ophthalmic division of trigeminal nerve
16
Q
Iris
A
- Colored diaphragm
- Surrounds pupil
17
Q
Orbital Septum
A
- Membranous sheet
- Attaches to orbital rim
- Separates orbit from periorbital region
18
Q
Lacrimal gland
A
- Produces tears that are secreted through the lacrimal ducts
- Tears wash across eye and drain into the nasolacrimal duct
- Empties into inferior nasal meatus in the nasal cavity
19
Q
Presynaptic parasympathetics of the Lacrimal gland originate
A
- In the pons
20
Q
Presynaptic parasympathetics originate in the pons travel in
A
- Facial nerve (nervus intermedius)
- Through pterygoid canal
- Zygomatic and lacrimal nerves
21
Q
Presynaptic parasympatehtics traveling in Facial nerve
A
- Greater petrosal nerve
- Greater petrosal joins deep petrosal forming nerve of pterygoid canal
22
Q
Presynaptic parasympathetics traveling through Pterygoid canal
A
- Enter pterygopalatine fossa
- Synapse on postsynaptics in pterygopalatine ganglion
23
Q
Presynaptic parasympathetics traveling in Zygomatic and Lacrimal nerves
A
- Synapse on the lacrimal gland
24
Q
Sympathetic innervation of Lacrimal gland
A
- Travel in ICA periarterial plexus
25
Postysynaptic sympathetics of Lacrimal gland originate
- Originate in superior cervical ganglion
26
Deep Petrosal nerve (Lacrimal sympathetics) is derived from
- The ICA periarterial plexus
| - Joins greater petrosal nerve to form nerve to pterygoid canal
27
Extra-Ocular muscles
- Muscles that move the eyeballs and eyelids
28
Superior Oblique innervation
- Trochlear nerve (CN IV)
29
Lateral Rectus innervation
- Abducens nerve (CN VI)
30
Extra-Ocular muscles innervated by oculomotor nerve (CN III)
- Inferior rectus
- Medial rectus
- Inferior oblique
- Superior rectus
- Levator palpebrae superioris
31
The 4 recti muscles originate from
- The common tendinous ring
32
Common Tendinous Ring
- Surrounds optic canal
| - Portion of superior orbital fissure
33
Superior Oblique origin
- Sphenoid bone separate from ring
34
Superior Oblique pathway
- Passes through trochlea
| - Redirects line of pull
35
Inferior oblique origin
- Anterior medial wall of orbit
36
Superior/Inferior oblique insertion
- Sclera
37
Muscle action based on primary position
- Based on muscle location and line of pull
| - Angled line of pull in the primary position, more than one function
38
Vertical axis eye movements
- Abduction
| - Adduction
39
Transverse axis eye movements
- Elevation
| - Depression
40
Anterior/Posterior axis eye movements
- Intorsion
| - Extorsion
41
Lateral Rectus function from primary position
- Abduction
42
Medial Rectus function from primary position
- Adduction
43
Superior Rectus function from primary position
- Elevates
- Adducts
- Intorsion
44
Inferior Rectus function from primary position
- Depresses
- Adducts
- Extorsion
45
Superior Oblique function from primary position
- Intorsion
- Depresses
- Abducts
46
Inferior Oblique function from primary position
- Extorsion
- Elevates
- Abducts
47
Eye muscles have
- Resting tone
48
Muscle activity depends
- Eye position
49
Muscles work
- Synergistically with each other
50
Pure depression from primary position involves
- Inferior Rectus
| - Superior Oblique
51
Coordination of both eyes requires
- The yoking of muscle actions
52
Eye position determines
- The primary muscle involved in producing a specific movement
53
Clinical use of eye position
- The eye is positioned so that one muscle dominates action
54
Superior Rectus and Inferior Rectus in the abducted position
- Superior rectus: elevation
| - Inferior rectus: depression
55
Superior Oblique and Inferior Oblique in the adducted position
- Superior oblique: depression
| - Inferior oblique: elevation
56
Oculomotor Nerve Palsy symptoms
- Ptosis
| - Down and out pupil
57
Abducens Nerve Palsy symptoms
- Loss of abduction
| - Medial deviation of eye
58
Trochlear Nerve Palsy symptoms
- Loss of depression while eye is adducted
| - Head tilt
59
Branches of Ophthalmic Nerve (V1) in the orbit
- Frontal
- Lacrimal
- Nasociliary
60
Frontal Nerve branches of the Ophthalmic Nerve
- Supraorbital
| - Supratrochlear
61
Nasociliary Nerve branches of the Ophthalmic Nerve
- Posterior ethmoidal
- Anterior ethmoidal
- Infratrochlear
- Long ciliary
- Sensory root to ciliary ganglia
62
Nerves in the Orbit
- Branches of Ophthalmic Nerve (V1)
- Trochlear nerve (CN IV)
- Optic nerve
- Abducens nerve (CN VI)
- Occulomotor nerve
- Zygomatic nerve (branch of V2)
63
Sensory root to ciliary ganglia
- Short ciliary connect ciliary ganglia to eyeball
64
Occulomotor Nerve divisions
- Superior division: SR, LP
| - Inferior division: MR, IR, IO, presynaptic parasympathetic neurons
65
Superior division of Occulomotor nerve innervates
- Superior rectus
| - Levator palpebrae
66
Inferior division of Occulomotor nerve innervates
- Medial rectus
- Inferior rectus
- Inferior oblique
- Presynaptic parasympathetic neruons
67
Ciliary ganglion
- Cell bodies of postsynaptic parasympathetic neurons to the inner eye
- Sensory and sympathetic nerve fibers pass through the ciliary ganglion
68
Only parasympathetic fibers synapse in the ciliary ganglion...
- Sensory and sympathetic fibers are just passing through
69
Parasympathetic to Intrinsic Eye Muscles
- Iris (pupil constriction)
| - Ciliary muscle (increase lens convexity, near vision)
70
Pathway of Parasympathetic to Intrinsic Eye Muscles
- Pre-synaptic neurons travel in oculomotor nerve
- Synapse in ciliary ganglion
- Postsynaptics travel in short ciliary nerve to inner eye
71
Sympathetic to Intrinsic Eye Muscles
- Iris (pupil dilation)
| - Ciliary muscle (decrease lens convexity, distant vision)
72
Pathway of Sympathetic to Intrinsic Eye Muscles
- Postsynaptics from superior cervical ganglion travel in IC perarterial plexus
- Pass through ciliary ganglion/short ciliary nerves and long ciliary nerve to inner eye
73
Ophthalmic Artery is a branch of
- Internal carotid artery
74
Branches of the Ophthalmic Artery
- Central retinal
- Lacrimal
- Posterior ciliary
- Muscular branches
- Supraorbital
- Anterior ethmoidal
- Posterior ethmoidal
- Supratrochlear
- Dorsal nasal
75
Veins of the Orbit
- Superior and inferior ophthalmic veins
