Eye Flashcards
Which nerve is most likely involved if a patient can look inward but not downward?
Trochlear
The trochlear nerve (IV) innervates the superior oblique muscle, which is responsible for downward movement of the eye when looking inward.
To check the integrity of the trochlear nerve, the patient should look:
Inward, toward the nose and downward
This movement tests the function of the superior oblique muscle innervated by the trochlear nerve.
If someone looking inward cannot look down, which nerve may be injured?
Trochlear (IV)
The inability to perform this action indicates a possible injury to the trochlear nerve.
To direct the gaze downward, which muscle must be active along with the inferior rectus?
Superior oblique
The coordinated action of these muscles is necessary for downward gaze.
The outermost layer of the optic nerve sheath is a continuation of the:
Meningeal dura
The meningeal dura extends to form the outer layer of the optic nerve sheath.
What is the inner lining of the eyelid called?
Palpebral conjunctiva
This mucous membrane covers the inner surface of the eyelid.
The ducts of the lacrimal gland open into the:
Superior fornix of the conjunctiva
This is where tears are released into the conjunctival sac.
Which extraocular muscle does not originate at or near the apex of the orbit?
Inferior oblique
The inferior oblique muscle originates from the maxilla rather than the apex of the orbit.
What signs would be noticed in the eye of a person who has taken a sympathetic blocking agent?
Ptosis and miosis (pin-point pupil)
Sympathetic blocking agents can lead to drooping of the eyelid and constriction of the pupil.
Which sign on the right side would confirm Horner’s syndrome in a patient with a drooping right eyelid?
Constricted pupil
Horner’s syndrome is characterized by ptosis, miosis, and anhidrosis.
What muscle must be paralyzed if a patient has ptosis?
Superior tarsal (smooth muscle portion of levator palpebrae)
This muscle is responsible for elevating the eyelid and its paralysis leads to drooping.
If a person is taking a sympathetic blocking agent, what would you notice in their eyes?
Ptosis and constricted pupil
These symptoms are indicative of the effects of sympathetic nerve blockade.
If a patient has a pituitary tumor involving the cavernous sinus, in which direction would they turn their eye to confirm damage to the abducens nerve?
Inward
Damage to the abducens nerve affects the ability to abduct the eye, leading to inward deviation.
What artery would likely be blocked if a patient is found to be blind in the right eye post-endarterectomy?
Central artery of the retina
This artery supplies blood to the retina, and blockage can lead to vision loss.
In a case of cavernous sinus infection, the route of entry to the cavernous sinus from the face was most likely the:
Ophthalmic vein
The ophthalmic vein can provide a pathway for infections from the face to the cavernous sinus.
