Eye Flashcards
Which bone makes up the roof of the orbit?
Orbital plate of the frontal bone
Which bone makes up the floor of the orbit?
The maxilla
Which structure is being indicated here?
Supraorbital notch/foramen
Which structures are being indicated here?
- Optic canal
- Superior orbital fissure
(Both part of sphenoid bone)
Which structures of which bone are indicated here?
Infraorbital canal and foramen of maxilla
Which bone of the orbit is indicated in blue?
Lacrimal
Which bone of the orbit is indicated in yellow?
Orbital plate of ethmoid bone
Which structure protects the eye from a direct blow?
The orbital margins
Which bones tend to fracture in an orbital blowout fracture and why?
Orbital plate of ethmoid bone (medial wall)
Maxilla (floor)
They are extremely thin - 0.5-1mm thick
How does a fractured zygoma tend to displace?
Tends to rotate medially to the floor of the orbit
Which structure is held within the infraorbital canal?
Infraorbital NVB
Which muscle makes up the ‘sphincter’ of the eye and what movement does it allow?
Obicularis oculi
Allows us to screw up the eyes
Which two ligaments attach the eyelid to the orbital rim?
Medial and lateral palpebral ligaments
Which structure is being indicated here and what is its function?
Tendon of levator palpebrae superioris
Contains skeletal and smooth muscle to elevate the superior eyelid
Which structures are being indicated here?
Superior and inferior tarsal plates
What is the orbital septum?
A sheet of fascia attaching to the peripery of the orbital rim
What does the orbital septum do?
Assists with preventing the spread of infection from superficial (periorbital cellulitis) to deep (orbital cellulitis)
What is the conjunctival fornix?
Where the conjunctiva is reflected off the sclera and onto the internal aspect of the eyelid
What is the name given to the orbital opening into the nasolacrimal duct?
Puncta
What is the name of the junction between the cornea and the sclera?
The limbus
What is the parasympathetic supply of the lacrimal gland?
CN VII
What is the name of the superior end of the nasolacrimal duct?
Lacrimal sac
Where should corneal reflections be seen normally?
Slightly medial i.e. nasal side of the pupil (as opposed to temporal side)
What are the two parts of the outer fibrous layer of the eye?
Sclera
Cornea
What is the function of the sclera?
Protects the eye
Provides attachment for the extraocular muscles
What is the function of the cornea?
Provides 2/3 of the eye’s refractive power
What are the three parts of the uvea?
The iris
The ciliary body
The choroid
What is the vascular layer of the eye?
The uvea
What is the function of the ciliary body of the eye?
Control of the iris and the shape of the lens
Secretion of aqueous humour
What is the photosensitive layer of the eye?
The inner retina
What is the function of the choroid?
Nutrition and gaseous exchange for the other layers
Which is the ‘vascular’ layer of the eye?
Choroid
What is the vitreous body?
A structure in the posterior segment which holds a clear gel consisting of ~98% water that provides pressure to hold the retina in place
What is the anterior chamber?
The space containing aqueous humour between the cornea and the iris
What is the posterior chamber?
Contains the lens and aqueous (humour) and is located between the iris and the vitreous body