Orbit Flashcards
What causes complete ptosis of the eyelid?
destruction of the occulomotor nerve or one of its branches to the levator palpebrae superioris muscle
what nerve innervates the levator palpebrae superioris muscle?
occulomotor nerve
what innervates the tarsal muscle?
postganglionic sympathetic fibers
what is Horner’s syndrome and what is a classic sign?
usually involves paralysis of the tarsal muscle; slight ptosis
where are the ciliary glands located?
in the subcutaneous layer of the orbit
What sends the preganglionic parasympathetics to the sphenopalatine ganglion?
the superior salvatory nucleus
what is the pre-ganglionic parasympathetic nerve that will eventually synapse in the sphenopalatine ganglion?
greater superficial petrosal nerve
which nerve does the greater superficial petrosal nerve branch off of?
facial nerve (CN VII)
where do the postganglionic parasympathetic fibers go after leaving the sphenopalatine ganglion?
to the lacrimal gland- via the maxillary, zygomatic, and lacrimal nerves
what sends postganglionic sympathetic fibers to the internal carotid plexus and eventually the sphenopalatine ganglion?
superior cervical ganglion
what is the post-ganglionic sympathetic nerve that will eventually travel to the spehnopalatine ganglion?
deep petrosal nerve
what do you get when you fuse the greater superficial petrosal nerve and the deep petrosal nerve?
vidian nerve
The nasolacrimal duct empties tears into what?
inferior meatus
forces applied to the temporal, maxillary, and frontal regions are transmitted where? and cause what?
to the optic canal and cause bony deformations
what portion of the optic nerve is the most frequent site of injury in cases of traumatic optic neuropathy?
the intracanalicular portion of the optic nerve
what does traumatic optic neuropathy result in?
immediate or slowly progressive loss of vision in the affected eye
what does the inferior orbital fissure convey?
the infraorbital artery, infraorbital nerve, and the zygomatic nerve
what does the superior orbital fissure convey?
CN III, IV, first part of V, and VI
what causes a blow-out fracture?
trauma to the front of the eyeball or a depressed fracture of the zygomatic bone (which is displaced medially
Which le forte fracture is an extensive trnasverse fracture of the face involving many facial bones and both orbits (panda bear appearance)?
Le forte type III
which le forte fracture is a transverse fracture of the maxillae just above the alveolar processes?
le forte type I
which le forte fracture is a pyramidal-shaped fracture of the maxillae usually involving part of the medial margin of one of the orbits?
le forte type II
paralysis of the levator palpebrae superioris results in what?
complete ptsosis
paralysis of the superior rectus results in what?
inability to abduct and elevate the affected eye
paralysis of the medial rectus results in what?
inability to adduct the affected eye
paralysis of the inferior rectus results in what?
inability to abduct and depress the affected
paralysis of the inferior oblique results in what?
inability to adduct and elevate the affected eye
paralysis of the superior oblique results in what?
inability to adduct and depress the affected eye
paralysis of the lateral rectus results in what?
inability to abduct the affected eye
if a patient presents with complete ptosis of the eyelid, external strabusmus, and the eye is directed outward, dilated and unreactive pupils, what do they have?
occulomotor palsy
if a patient presents with the inability to adduct and depress the eye (inability to look in and down)
trochlear palsy
if a patient has an inability to abduct the affected eye what do they have?
abducens palsy
what are the causes of hydrocephaly?
it is congenital
hydrocephaly causes compression of what nerve?
CN VI
Compression of CN VI causes what?
sundown gaze
what is the blink reflex important for?
testing brain stem function
what is another name for the blink reflex?
direct and consensual corneal reflex
what is the afferent nerve of the corneal reflex?
nasocilliary nerve ( CN V)
what is the efferent nerve of the corneal reflex?
zygomatic branch of the facial nerve
what is the chief blood supply to the orbit?
the opthalmic artery
what is the blood supply of the optic nerve?
the central retinal artery
the presence of blood in the anterior chamber of the eyeball usually due to trauma and rupture of the great arterial circle of the iris
hyphema
what vessel is involved with a hyphema?
arterial circle of iris
rupture of the deep pericorneal plexus- bleeding restricted to the subjunctival tissue
subconjunctival hemorrhage
what vein in the orbit leads to the cavernous sinus?
superior opthalmic vein
where is the maxillary sinus located?
beneath the orbit
