Anatomy Flashcards
What 7 bones make up the orbit of the eye?
Frontal
Zygomatic
Maxilla
Palatine
Sphenoid
Ethmoid
Lacrimal
Does the nasal bone make up part of the orbit?
No
What passes through the optic canal?
Optic nerve
Ophthalmic artery
This opening is found on the sphenoid bone.
Which cranial nerves are responsible for movement of the eye?
CNIII (trigeminal)
CNIV (trochlear)
CNVI (abducens)
What is a blowout fracture?
When major force is exerted on the orbital rim, the pressure is transferred from the thicker bones to the thinner bones.
What is a complication of a trap-door/blowout fracture?
Contents of the orbit may become trapped.
What is the name of the sphincter muscle that completely encircles the orbit?
Obicularis oculi
This is innervated by CNVII (facial nerve).
What is the role of the levator palpebra superioris?
Elevation of the upper eyelid.
Is the levator palpebra superioris mainly skeletal or smooth muscle?
Mainly skeletal, although has a smooth muscle component.
The area related to smooth muscle control may be called Mueller’s muscle.
Which gland is found superolateral to the eye?
Lacrimal gland
This is innervated by CNVII (facial nerve).
What is the role of the iris?
It is a diaphragmatic/sphincter-like muscle that controls the amount of light entering the eye.
What 2 parts make up the fibrous layer of the eye?
Cornea
Sclera
What are the 3 layers of the eye?
Fibrous
Uvea/Vascular
Retina
Which part of the eye is responsible for 2/3rds of the total refractive power?
Cornea
What 3 components make up the uvea layer of the eye?
Iris
Ciliary body
Choroid
What area of the eye is considered to be the anterior chamber?
All of the structures located anterior to the lens.
What area of the eye is considered to be the posterior chamber?
All of the structures behind the lens.
What is the limbus?
The angle found between the cornea and the sclera.
What is the indocorneal angle?
The angle between the iris and the cornea.
It is important in the pathology of glaucoma.
What is the purpose of aqueous humor?
It is a liquid required to provide nutrition to the avascular lens and cornea.
Production occurs in the posterior chamber, by the ciliary body.
Where is the aqueous humor resorbed?
Scleral venous sinuses located at the indocorneal angle.
If aqueous humor nourishes the cornea from the inside, what provides the surface area nutrition?
Lacrimal fluid (tears).
What controls intra-ocular pressure?
The balance between production and resorption of aqueous humor.
Input must be equal to output to prevent issues.
What may result from raised intra-ocular pressure?
Ischaemia of the retina
Glaucoma
Which artery supplies the majority of bloodflow to the eye?
Ophthalmic artery
This is a branch of the internal carotid artery.
What is an end artery?
An artery with insufficient anastomoses.
This means that blockage of this will leave the tissue supplied by this cut-off from their blood supply.
An example is the central retinal artery.