Orbit, Cavernous Sinus, And Eye Flashcards
(31 cards)
Bones of the orbit
The thinnest portion of the bones orbit is the _____ aspect.
Sphenoid Frontal Ethmoid Maxillary Lacrimal Zygomatic Palatine
Medial
What are three foramina in the orbit and what travels through these holes?
Supraorbital: supraorbital N
Superior orbital fissure: oculomotor N, trochlear N, ophthalmic division of trigeminal N, abducens N, ophthalmic V
Optic canal: optic N, ophthalmic A
The tendinous ring houses all the ____ of the eye.
The ____ assists in closing the eye. Innervated by _____ (temporal and zygomatic branches). What are the three parts of this muscle and what is their fx?
Muscles
Orbicularis oculi
CN VII
Palpebral: closing of lid
Lacrimal: increased lid contact to eye, dilates lacrimal sac
The ____ is skeletal muscle and acts as a direct antagonist to the orbicularis oculi and exposes (opens) the eyeball along with the superior tarsal muscle by lifting the eyelid. Innervated by _____.
Levator palpebrae superioris (LPS)
CN III
The _____ is smooth muscle and inserts onto the superior tarsus (dense CT). Innervated by postganglionic fibers originating from level of ____.
The _____ are modified sweat/sebaceous glands. Infection to these glands form a ____.
Superior tarsal m
T1
Ciliary glands (mebomian/moll’s glands)
Stye
Tears are formed by the ____ at the supero-lateral aspect of the orbit. Tears are drained by the ____ located on the medial aspect of the orbit and eventually drain into the ____.
Lacrimal gland
Lacrimal canaliculi
Inferior meatus
Lacrimal gland -> lacrimal canaliculi -> lacrimal sac -> nasolacrimal duct -> inferior concha
Sympathetic innervation of the lacrimal gland is the _____.
The parasympathetic innervation of the lacrimal gland starts in the ____ nucleus -> facial N(CN VII)/greater petrosal N -> Vidian N -> ______ -> zygomatic N (CN V2)-> _____.
Superior cervical ganglion (carotid plexus)
Superior salivatory nucleus
Sphenopalatine ganglion (pterygopalatine ganglion)
Lacrimal N (CN V1)
What are the three main branches of CN V1?
Nasociliary N
Frontal N -> supraorbital N and supratrochlear N
Lacrimal N
Fractures of the bony orbit due to high velocity trauma?
Caused by?
Clinical signs?
What causes the diplopia (double vision usually of upward gaze)?
Blow-out fracture
High-velocity trauma (AP direction)
Periorbital ecchymosis, edema, point tenderness, diplopia, decreased visual acuity, decreased pupillary reflex, displacement of structures into maxillary sinus
Due to entrapment of inferior rectus muscle (EOM)
Fractures of maxillary region of the skull called?
Caused by?
What are the three types?
Le forte fractures
High-velocity trauma
Type 1: above alveolar processes; avoids orbit
Type 2: pyramidal shape involving medial portion of orbit
Type 3: Craniofacial dysfunction; transverse fracture across both orbits and nasofrontal sutures; separation from base of skull; caused by severe lateral force trauma
What are clinical signs of Le forte fractures?
Lower lip swelling; ecchymosis; damaged teeth (type 1); periorbital edema; CSF rhinorrhea; nasal disfigurement (type 2); panda facies; complete mobility of facial skeleton; antimongoloid slant (type 3)
Paired dural venous sinuses are found between the ____ and ____ layers of the dura mater. They are parasagittal to the hypophysis and bounded by brain, sphenoid bone, and temporal bone.
Sphenoidal sinuses are inferior to the ____.
Endosteal and meningeal
Cavernous sinus
What six structures are contained in the cavernous sinus?
CN III, CN IV, CN V1, CN V2, internal carotid A, CN VI
OTOM CAT
Cavernous sinus is a ______ that drains blood from the ophthalmic veins eventually delivering blood to the ____ and the IJV.
Paired dural venous sinus
Petrosal sinuses
_____ is enlargement of sinus due to venous congestion secondary to hematological obstruction (thrombus)
Caused by?
Infection spreading to the facial V leads to _____.
Clinical signs?
Cavernous sinus thrombosis
Infection (mainly bacteria), thrombophilic disorders
Leads to obstruction in smaller compartments (petrosal sinus)
Unilateral periorbital edema and proptosis, HA, photophobia, impingement syndrome (CN VI)
What are the fibrous layers of the eye?
Vascular layers?
Inner layers?
Sclera: covered by bulbar conjunctiva, thin highly vascular membrane; pink eye is and inflammation of sclera
Cornea
Choroid: between sclera and retina
Ciliary body: attachment for lens that connects choroid to iris; controls thickness of lens; secretes aqueous humor (ciliary processes)
Retina
___ is the point for retinal neuronal axons to form optic N.
_____ area for high resolution, color distinction vision.
___ is swelling to optic disc due to increases in CSF.
Optic disc
Macula lutes
Papilledema
_____ is a blinking response arc directed by what two cranial nerves?
Describe the input verse the output?
Corneal reflex
CN V, CN VII
Input: nasociliary N/long ciliary N (CN V1)
Output: facial N -> orbicularis oculi (CN VII)
_____ is a pigmented structure acting as a boundary between the anterior and posterior compartments of the eye.
Hole in iris leading to lens is ____.
Iris
Pupil
Two muscles in the iris that controls the diameter of the pupil?
Sphincter pupillae m -> constricts (miosis; parasympathetic)
Dilator pupillae m -> dilates (midriasis; sympathetic)
Pupillary constriction reflex
J
Pupillary dilation reflex
J
The ____ controls the lens to focus light. They are attached to _____ which attach to lens.
Parasympathetic stimulation causes the ciliary muscle to ____ and zonular fibers to ___.
Ciliary muscle
Zonular fibers
Constrict; relax
A _____ reflex focuses on close structures/objects.
Outputs are sent out by occipital lobe to perform three fx simultaneously?
Cortically mediated
Convergence (pupils adduct)
Pupillary constriction
Lens thickening (nearsightedness)
