orbit and cavernous sinus CIS

Question 1

lacrimal apparatus, route of tears

Answer 1

lacrimal canaliculi–>lacrimal sac–>nasolacrimal duct–>inferior nasal meatus (why tears cum out of nose)

Question 2

oculumotor nerve palsy gaze

Answer 2

downward and outward gaze, dilated pupil

Question 3

loss of innervation to what muscle causes complete ptosis in a patient
-what nerve

Answer 3

levator palpebre superioris

oculomotor nerve

Question 4

mydriasis seen in oculomotor nerve palsy is caused by disruption of what neural pathway?

Answer 4

parasympathetic fibers to the sphincter pupillae m

Question 5

signs of oculomotor nerve palsy

Answer 5

down and out eye
complete ptosis
pupil dilation

Question 6

which area in the brain is responsible for consensual light reflex

Answer 6

posterior commisure

Question 7

direct light reflex pathway

Answer 7

retina–>optic nerve–>optic tract–>brachiam of superior colliculus–>superior colliculus–>pretectum–>edinger-westphal nucleus–>occulomotor nerve–>ciliary ganglion–>pupillary constrictor muscles

Question 8

horner’s syndrome triad of signs

Answer 8

slight ptosis, miosis and anhydrosis

Question 9

causes of horner’s syndrome

Answer 9

mass effect (pancoast tumor)
aortic or carotid artery aneurysm
idiopathic or congenital

Question 10

decreased light and dilating pupil pathway

Answer 10

retina–>optic nerve–>superior colliculus–>pretectum–>reticular formation–>lateral reticulospinal tract–>preganglionic symp neruons–>superior cervical ganglion–>pupillary dilator muscles

Question 11

argyll robertson pupil

Answer 11

pupil constricts when object brought towards eye but not when light shined on it
(normal accommodation abnormal light relfex)
-associated with syphllyis (Garrett)

Question 12

triad of accommodation

Answer 12

convergence of gaze
pupillary constriction
thickening of lens

Question 13

holmes adie pupil

Answer 13

tonically slow reacting pupil to light
normal response to accommodatino
caused by infection but not syphillis (not garrett)

Question 14

hyphema

Answer 14

blood pooling in anterior chamber of eye due to rupture of arterial circle of iris

Question 15

subconjunctival hemorrhage

vessel involved and description

Answer 15

deep pericorneal plexus

-bleeding restricted to subconjunctival tissue or bulbar fascia

Question 16

conjunctivitis vessel involved and description

Answer 16

superficial pericorneal plexus

-red inflammation or irritation of conjunctiva

Question 17

le fort 1 fracture

Answer 17

• horizontal maxillary fracture
• separates teeth from upper face
• fracture line passes through alveolar ridge, lateral nose and inferior wall of maxillary sinus

Question 18

le fort 2 fracture

Answer 18

pyramidal fracture with teeth at the pyramid base
can involve orbit but only 1 side
fracture passes through alveolar ridge, lateral walls of maxillary sinus and inferior orbital rim and nasal bones

Question 19

le fort 3 fracture

Answer 19

both orbits involved

fracture line passes through nasofrontal suture orbital wall and zygomatic arch

Question 20

branches of nasociliary nerves

Answer 20

posterior ethmoid
anterior ethmoid
long ciliary nerves

Question 21

where do the superior and inferior ophthalmic veins drain

Answer 21

into the cavernous sinus

Question 22

ophthalmic artery gives off what arteries

Answer 22

supraorbital
posterior ethmoidal 
anterior ethmoidal 
lacrimal
short ciliary

Question 23

clinical findings with blow out fracture

Answer 23

• enophthalmos: due to increased orbital volume
• diplopia: due to extra ocular muscle entrament
• orbital emphysema: especially when frature in adjacent paranasal sinus
• malar region numbness: due to injury to inferior orbital nerve

Question 24

where is the central retinal artery located

Answer 24

right in middle of optic nerve

Question 25

presentation of central retinal artery lesion

Answer 25

one eye goes black

abrupt and painless

Question 26

what exits the superior orbital fissure

Answer 26

V1
cranial nerves III,IV,VI
opthalamic vein

Question 27

branches of V1

Answer 27

Nasociliary nerve
Frontal nerve
    -supraorbital
    -supratrochlear
Lacrimal nerve

Question 28

corneal reflex

Answer 28

touch cornea 
receptor nerve endings
afferent: nasociliary n, especially long ciliary
sensory nucleus: descending nucleus of V
motor nucleus: facial nucleus
efferent: facial nerve
effector: orbicularis oculi muscle