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LECOM MS1 Gross Anatomy - Head/Neck 2022 (+Shelf) > Orbit & Eye > Flashcards

Orbit & Eye Flashcards

1
Q

What is in the bony orbit?

A

Zygomatic, ethmoid, maxillary, frontal, lacrimal, palatine

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2
Q

What is a “blowout” fracture?

A

result in bleeding into maxillary sinus; may entrap inferior rectus (restricted upward gaze) or inferior oblique muscle and/or lacerate the infraorbital n. (sensory loss on lower eyelid & maxilla)

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3
Q

What is a medial orbital fracture? What does in impact?

A

impact the ethmoid&raquo_space; sphenoid sinus; can entrap
medial rectus (restricted lateral gaze)

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4
Q

What are the structures of the eyelids?

A

Skin, loose CT, muscular layer, tarofascial layer, conjunctiva

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5
Q

What lubricates the eye?

A

Lacrimal gland along with accessory lacrimal glands

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6
Q

The lacrimal gland’s innervation is…

A

GSA, GVE parasympathetics via CN VII, and GVE sympathetics via T1-T4

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7
Q

Where is the collecting apparatus situated?

A

Medial canthus

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8
Q

What does sympathetics control in the eye?

A

Blood

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9
Q

What does parasympathetics control in the eye?

A

Secretion
Injury to parasympathetics -> dry eye

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10
Q

The suspensory ligament of Lockwood…

A

Holds eyeball inside eye

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11
Q

What are the internal structure of the eye?

A
  1. Fibrous layer
  2. Vascular layer
  3. Nervous layer
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12
Q

What is the fibrous layer continuous with?

A

Dura

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13
Q

What does the fibrous layer make up?

A

Sclera

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14
Q

What is the sclera?

A

Covers 5/6 of the eye, opaque, lamina cribrosa, major attachment of eye muscles

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15
Q

What is continuous with the sclera?

A

Cornea, transparent

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16
Q

What does the vascular layer make up?

A

Choroid

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17
Q

What is the choroid continuous with?

A

Arachnoid + pia

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18
Q

What is the choroid?

A

Covers about 5/6 of the eye, has the optic nerve within

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19
Q

If we block scleral venous sinus, what can occur?

A

Glaucoma

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20
Q

Where is the ciliary body?

A

Vascular layer

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21
Q

What is the ciliary body?

A
  • from ora serrata to scleral spur
  • ciliary process and zonular fibers
  • secretes aqueous humor
  • ciliary muscle
  • scleral venous sinus
  • anterior and posterior chambers
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22
Q

How is the lens anchored?

A

Zonular fibers

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23
Q

What is lens?

A
  • found at the junction of the anterior and posterior compartments
  • anterior surface contacts the iris
  • posterior surface contacts the vitreous body
  • ciliary processes and zonular fibers
  • cataract
24
Q

The action of ciliary muscle when relaxed is…

A

Big opening, tight zonula fibers, lens is flat & skinny

25
Q

The action of ciliary muscle when contracted is…

A

Small opening, slack zonula fibers, lens is rounded & fat

26
Q

What is within the iris?

A

Sphincter pupillae (CN III)
Dilator pupillae (sympathetics, T1-T4)

27
Q

What is the function of the iris?

A

Split into anterior & posterior compartments

28
Q

Pupil is…

A

Empty!

29
Q

When are dilator pupillae most active?

A

Scared, sympathetics, dark room

30
Q

When are constrictor pupillae most active?

A

Surrounded by light

31
Q

What is in the nervous layer?

A

Retina, macula layer, optic disc

32
Q

What does the retina contain?

A
  • contains pigmented epithelium and photoreceptive cells
  • neural and non neural parts
  • from ora serrata to optic disc
33
Q

What is macula layer?

A
  • an area of the retina with a high concentration of photoreceptors
  • fovea centralis - area of highest visual acuity, a tea cup-like depression
34
Q

What is optic disc?

A
  • where optic nerve fibers leave the eye
  • no photoreceptors here = blind spot
  • entry/exit of the central retinal vessels
35
Q

If the macula is flattened, what occurs?

A

Papilledema

36
Q

What is the vitreous body?

A

 gel-like mass that fills the posterior chamber
 functions in refraction of light and maintains the shape of the globe
 hyaloid canal

37
Q

What is the vascular supply of the eye?

A

Ophthalmic artery

38
Q

What are the branches of the ophthalmic artery?

A
  • central artery of the retina
  • muscular
  • ciliary
  • lacrimal
  • supraorbital
  • anterior and posterior ethmoidal
  • meningeal
  • supratrochlear and dorsal nasal
39
Q

What is amaurosis fugax?

A

Vision loss in one eye, fleeting blindness
Sign of impending stroke

40
Q

What is the venous drainage of the eye?

A
  • Superior ophthalmic vein
  • Inferior ophthalmic vein
  • Infraorbital vein
  • Central vein of the retina
    All drain into cavernous sinus -> pterygoid plexus
41
Q

What is the sensory innervation of the eye?

A

CN V1 (ophthalmic nerve)
- Nasociliary
- Frontal nerve
- Lacrimal nerve
CN V2 (maxillary nerve)
- infraorbital & zygomatic

42
Q

What is present within corneal reflex?

A

CN V -> trigeminal ganglion -> close eye -> orbicularis oculi -> CN VII

43
Q

The ciliary ganglion is a …

A

Parasympathetic ganglion

44
Q

What does the ciliary ganglion contain?

A

Cell bodies that innervates the intrinsic eye muscles

45
Q

What are the three roots of the ciliary ganglion?

A
  1. Sensory - returning sensory information from the eye; CN V1
  2. Sympathetic - from internal carotid plexus via ophthalmic artery or CN III; supplies the dilator pupillae
  3. Motor - contains preganglionic axons from CN III to sphincter pupillae and ciliary muscles
46
Q

Postganglionic sympathetic axons….

A
  1. arise from the superior cervical ganglion and travel along the cavernous plexus
  2. reach the orbit on ophthalmic artery, CN III or CN V
  3. traverse the ciliary ganglion without synapse
  4. Innervate the dilator pupillae muscle and superior tarsal muscle
47
Q

What occurs when paralysis of dilator pupillae occurs?

A

Miosis

48
Q

What occurs when paralysis of superior tarsal muscle?

A

Mild ptosis

49
Q

What are the muscles of the eye innervated by?

A

Oculomotor nerve (CN III), trochlear nerve (IV), abducens nerve (VI)

50
Q

Key points of the oculomotor nerve in the eye

A
  • arises from: cavernous sinus:
  • through the supraorbital fissure
  • divides into: parasympathetic root to ciliary ganglion
51
Q

If anisocoria occurs in the dark…

A

Sympathetics injury

52
Q

If anisocoria occurs in the light…

A

CN III injury

53
Q

What are the extraocular muscles?

A
  • a common tendinous ring is derived from the orbital fascia
  • neurovascular structures and the common tendinous ring
54
Q

What is levator palpebrae?

A
  • arises from the roof of the orbit and attaches to the upper eyelid, associated with superior tarsal muscle
  • Innervation: CN III
55
Q

Compressive injury of CN III?

A

PCOM aneurysm, abscess
* a painful and complete oculomotor palsy that involves the pupil is most often an aneurysm
* compressive injuries can affect the pupil but spare eye movements (because of the superficial location of the GVE axons in CN III)

56
Q

Ischemic injury of CN III?

A
  • can spare GVE axons
  • a painless oculomotor palsy that spares the pupil is most often microvascular

LECOM MS1 Gross Anatomy - Head/Neck 2022 (+Shelf) (29 decks)

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