Orbit

Front 1

What are the parts of the conjunctiva?

Back 1

Palpebral - inner surface
Bulbar - reflected on anterior portion of cornea and sclera of eyeball

Front 2

Where does the lacrimal gland secrete tears?

Back 2

superior conjunctival fornix

Front 3

What muscle closes the eyelid? What innervates it?

Back 3

Orbicularis oculi. Facial nerve.

Front 4

What is the muscle that opens the eyelid?

Back 4

Levator palpebrae superior

Front 5

What innervates levator palpebrae superior?

Back 5

Two nerves innervate the muscle.

Striated (voluntary) : oculomotor (CN III)

Smooth (Involuntary): sympathetic

Front 6

What are the possible causes of a drooping eyelid?

Back 6

Oculomotor nerve (CN III) lesion

OR

sympathetic lesion

Front 7

What is the most superior muscle of the orbit?

Back 7

Levator palpebrae superioris

Front 8

What is ptosis of the eyelid?

Back 8

Drooping

Front 9

What are 4 symptoms of Horner syndrome? What is it?

Back 9

Caused by damage to sympathetic nerves to face.

1) Ptosis
2) Decreased sweating
3) Miosis (contraction of pupil)
4) Flushing of face

Front 10

What does the muscular portion of the eyelid contain?

Back 10

1) Palpebral part of orbicularis oculi

2) Aponeurosis of levator palpebrae superioris

Front 11

What is Mueller's muscle?

Back 11

AKA superior tarsal muscle. the sympathetic muscle that opens the eyelid.

Front 12

What is the bulbar sheath?

Back 12

Sheath around the eyeball that is continuous with the sheaths surrounding the extraocular muscles. Make sure eyeball doesn't move around too much.

Front 13

How is lacrimal fluid drained?

Back 13

Through the nasolacrimal duct. lacrimal puncta are located at medial ends of upper and lower eyelids, leading to lacrimal canaliculi, draining into lacrimal sac

Lacrimal punctum --> Lacrimal canaliculi --> Lacrimal sac --> Nasolacrimal duct --> Nasal cavity

Front 14

Where is the lacrimal gland?

Back 14

Latero-superior border of orbit

Front 15

what innervates lacrimal gland?

Back 15

Lacrimal nerve. Branch of ophthalmic division of Trigeminal nerve (CN V).

Superior salivatory nucleus -> Greater petrosal nerve ( of CN VII) --> n. of pterygoid canal --> SYNAPSE IN PTERYGOPALATINE GANGLION. --> Then travel to V2-->Communication branch --> Lacrimal n.

Front 16

What is the superior salivatory nucleus?

Back 16

Cranial nerve nucleus for CN VII (facial) in brain stem. Provides parasympathetic efferents.

Some of the preganglionic fibers travel along the greater petrosal nerve through the pterygoid canal (where they join the postsynaptic fibers of the deep petrosal nerve and are called the n. of pterygoid canal) and synapse in the pterygopalatine ganglion, whereupon the postganglionic, postsynaptic, efferent fibers travel to innervate the lacrimal gland and the mucosal glands of the nose, palate, and pharynx.

Front 17

What does the greater petrosal nerve innervate (wrt orbit)?

Back 17

parasympathetic innervation to Lacrimal gland

Front 18

Where do preganglionic parasympathetics coming from the superior salivatory nucleus synapse, on the way to the lacrimal gland?

Back 18

Pterygopalatine ganglion

Front 19

Parasympathetic innervation of lacrimal gland.

Back 19

Superior salivatory nucleus --> facial nerve --> (splits to) greater petrosal nerve --->Pterygopalatine ganglion. Synapses here.

Then travels via maxillary division of CN V to lacrimal nerve.

Front 20

What 7 bones make up the orbit?

Back 20

Frontal; Zygomatic; Maxilla; Lacrimal; Sphenoid; Ethmoid; Palatine

Front 21

What does blinking do to get tears out?

Back 21

The lacrimal part of the orbicularis oculi squeezes the lacrimal canaliculi to pump tears out into lacrimal sac

Front 22

Parasympathetic Innervation of Lacrimal Gland

Back 22

1. Superior Salivatory Nucleus
2. Facial Nerve
3. Greater (Superficial) Petrosal Nerve
4. Nerve of Pterygoid Canal
5. Maxillary division of CN V
6. Communicating Branch
7. Lacrimal Nerve

Front 23

What is the periorbita?

Back 23

The periosteum lining orbit

Front 24

What does the optic canal transmit?

Back 24

Optic n and opthalmic artery

Front 25

Is the ophthalmic v inside the annulus tendineus?

Back 25

No

Front 26

What goes thru inferior orbital fissure?

Back 26

Infraorbital n and a

Front 27

What goes thru the superior orbital fissue?

Back 27

CN III: Oculomotor
CN IV: Trochlear
CN V, Ophthalmic division
CN VI: Abducens

Ophthalmic veins

Front 28

What structures going thru the superior orbital fissure inside the annulus tendineus/common tendinous ring?

Back 28

CN III: Superior and inferior division of oculomotor

Nasociliary n
Abducens

Look for Three (mnemonic for what's NOT going thru - Lacrimal, Frontal, Trochlear)

Front 29

What muscles arise from the annulus tendineus?

Back 29

The 4 rectus muscles (sup, inf, med, lat)

Front 30

What are the 6 extraocular muscles?

Back 30

Sup, inf, med, lat rectus
Superior oblique, Inferior oblique

Front 31

What is the innervation of the extraocular muscles.

Back 31

All are CN III except lateral rectus (CN VI) and superior oblique (CN IV)

LR6SO4 (LR sulfate) is mneumonic

Front 32

What movements does superior rectus cause?

Back 32

Adduction in addition to elevation

Front 33

What movements does inferior rectus cause?

Back 33

Adducts in addition to depression

Front 34

What movement does the superior oblique cause?

Back 34

Moves back of eyeball UP and INWARD, so causes one to look DOWN and OUT

Front 35

Diagnosis of Trochlear Nerve
(CN IV) Lesion

Back 35

Trochlear nerve only innervates superior oblique, which causes the motions DOWN and OUT.



However, get them to look IN, then DOWN.

Front 36

What does the ophthalmic division of the trigeminal nerve divide into once it enters the superior orbital fissue?

Back 36

Lacrimal, Frontal, Nasociliary

Front 37

What large artery does the ophthalmic artery branch off?

Back 37

Internal carotid a

Front 38

What are the 9 branches of the ophthalmic artery?

Back 38

1) Anterior ethmoid
2) Posterior ethmoid
3) Short posterior ciliary
4) Long posterior ciliary
5) Lacrimal (meningeal branch attaches to mid meningeal artery)
6) Supraorbital
7) Supratrochlear
8) Dorsal nasal
9) <b>Central Retinal</b>

Front 39

What is the artery you're looking for with an ophthalmoscope, variations of which can have impt clinical consequences?

Back 39

Central Retinal

Front 40

What structure does the central retinal a eventually travel with?

Back 40

Center of optic nerve

Front 41

What are the two main veins the ophthalmic veins drain into?

Back 41

Superior and inferior ophthalmic veins

Front 42

What sinus do the ophthalmic veins drain into? What do they go thru to get there?

Back 42

Cavernous sinus, via superior orbital fissure

Front 43

What is the danger area of the face? Why is it called this?

Back 43

Triangle like region from cheek below orbit around upper lips and along sides of nose. Called this because infections in this area can spread into the cranium via cavernous sinus via ophthalmic veins
* trochlear nerve (CN IV)
* abducens nerve (CN VI)
* ophthalmic nerve, the V1 branch of the trigeminal nerve (CN V)
* maxillary nerve, the V2 branch of CN V

Front 44

What nerves go thru the intercavernous sinus?

Back 44

CN III, IV, VI, V(1)
NOT V(2)

Front 45

What are symptoms of infection in face that's gone to cranial cavity?

Back 45

- red line showing path of infection
- exophthalmos (bulging eye)
- edema of conjunctiva
- impaired eye movements

Front 46

How to diagnose an oculomotor n. lesion?

Back 46

-eyelids will droop, be difficult to open
-Look at eye movements (everything but LR6SO4)
-Size and symmetry of pupils (pupils will be constricted due to parasympathetic activity)

Front 47

Where do the preganglionic fibers associated with CN III arise?

Back 47

Edinger Westphal nucleus in brainstem

Front 48

Where do the preganglionic fibers associated with CN III travel?

Back 48

They arise in Edinger Westphal nucleus, then go thru ciliary ganglion. They synapse there. Then they go thru short ciliary nerves to eyeball where they pass to sphincter pupillae muscle and muscle of accomodation

Front 49

What are the three roots of the ciliary ganglion?

Back 49

Motor, Sensory, Sympathetic

Front 50

What is the motor root of the ciliary ganglion from?

Back 50

It's where the inf division of oculomotor nerve synapses.

Front 51

What is the sensory root of the ciliary ganglion from? What is function?

Back 51

Branch of nasociliary (which is branch of trigeminal). Carries sensation from eyeball back to CNS from short ciliary n.

Front 52

What is the sympathetic root of the ciliary ganglion from? What is function?

Back 52

From the deep petrosal n, carries postganglionic fibers that travel from superior cervical ganglion along carotid plexus. These fibers are responsible for pupil dilation

Front 53

What does the lateral retina receive input from? The nasal?

Back 53

Lateral receives input from medial visual field. Nasal receives from lateral.

Front 54

What fibers cross at the optic chiasm?

Back 54

Fibers from nasal retina

Front 55

What can pituitary tumors cause?

Back 55

Since they would be right at the chiasm, they would damage the nasal retina fibers, and the lateral visual fields would be lost.

Front 56

What is bitemporal hemianopsia?

Back 56

Aka tunnel vision. Results when nasal retina fibers (which get input from lateral visual field) are lost, possibly from a pituitary tumor

Front 57

How does the light reflex work?

Back 57

Optic nerve is sensory limb, oculomotor ciliary ganglion is efferent (motor) limb.

Front 58

How does dilation of pupil work?

Back 58

Occurs in dim light or during stress.

Afferent limb for dim light is optic nerve. For stress it can be several things.

Eferent limb is upper thoracic spinal cord as ultimate source of sympathetic preganglionic fibers, superior cervical ganglion, carotid plexus, etc.

Front 59

How does the blink (corneal) reflex work?

Back 59

The afferent is the ciliary nerves (thru nasociliary) to trigeminal n (CN V). Efferent is via facial nerve to orbicularis oculi