W3: S1+2 - Orbit and Eye Flashcards
What structures pass through the optic foramen (optic canal)?
- Optic nerve
- Opthalmic artery
What 5 structures pass through the superior orbital fissure?
- Abducens nerve
- Occulomotor nerve
- Trochlear nerve
- Opthalmic division of trigeminal nerve
- Opthalmic veins
What nerve passes through the inferior orbital fissure?
Maxillary division of trigeminal
What are the main contents of the orbit?
- Eyeball
- Extrinsic ocular muscles
- Ligaments supporting the eye
- Optic nerve
- Branches of opthalmic artery
- Lacrimal apparatus
- Opthalmic veins
What are the three component parts of the eyeball?
Outer fibrous layer
Middle vascular layer
Inner sensory layer
What structures make up the outer fibrous layer and is it a complete layer?
- Cornea
- Sclera
It is a complete layer
What structures make up the middle vascular layer of the eye and is it a complete layer?
- Ciliary body
- Iris
- Choroid
Incomplete layer anteriorly as the pupil
What structures make up the inner sensory layer and is it a complete layer?
- Retina
Only present posteriorly
What is the name given to the watery fluid in the anterior segment of the eye?
Aqueous humor
What is the name given to the gel like fluid in the posterior part of the eye?
Vitreous humor
What secretes aqueous humor and where?
Ciliary body
In the posterior chamber
What are the three intrinsic muscles of the eye?
Ciliaris
Sphincter pupillae
Dilator pupillae
Where is the ciliaris muscle located?
The vascular layer surrounding the iris
What is the action of the ciliaris?
Used in accomodation
What is the innervation of the ciliaris?
Parasympathetic
- Occulomotor
Where is the sphincter pupillae located?
Pupillary border of the iris
What is the action of the sphincter pupillae?
Narrowing the pupil
What is the innervation of the sphincter pupillae?
Parasympathetic
- Occulomotor nerve
Where is the dilator pupillae located?
Outer to inner border of the iris
What is the action of the dilator pupillae?
Widens the pupil
What is the innervation of the dilator pupillae?
Sympathetic innervation
What eye movement is looking up?
Elevation
What eye movement is looking medially?
Adduction
What eye movement is looking down?
Depression
What eye movement is looking towards the temples?
Abduction
What is the name given to the eye movement that keeps the eye on a level plane when the head is tilted?
Intorsion and extorsion
What are the 6 extrinsic muscles of the eye?
4 Recti
- Lateral
- Medial
- Superior
- Inferior
2 Obliques
- Superior
- Inferior
Identify
A: Medial rectus
B: Superior rectus
C: Superior oblique
D: Inferior oblique
E: Inferior rectus
F: Lateral rectus
What other muscle is also considered an extrinsic eye muscle even though it has no effect on the eyeball itself?
Levator palpebrae superioris
What muscles are supplied by occulomotor nerve?
Recti
- Superior rectus
- Medial rectus
- Inferior rectus
Oblique
- Inferior oblique
Other
- Levator palpebrae superioris
What muscle is supplied by the trochlear nerve?
Superior oblique
- Remember this by the fact that the superior oblique is attached to a trochlea to allow it to turn the eye
What muscles are innervated by abducens nerve?
- Lateral rectus
What is the only muscle that does not arise from the posterior aspect of the orbit?
Inferior oblique
What ligaments prevent overadduction and overabduction of the eye?
Medial and lateral check ligaments
What is the function of the extrinsic suspensory ligament?
Resist the posterior pull of the recti
What branch of the ICA supplies the orbit and the eye, shown below
Opthalmic artery
