Orbit and eye Flashcards
What are the 3 formaina at the apex of the orbit?
The optic foramen, superior orbital fissure and inferior orbital fissure
What passes through the optic formane?
Optic nerve
Opthalmic nerve
What passes throguh the superior orbital fissure?
- Cranial Nerve VI (Abducens)*
- Cranial Nerve IV (Trochlear)*
- Cranial Nerve III (Oculomotor)*
- Ophthalmic* division of Cranial Nerve V (V1)
- Ophthalmic veins*
What passes through the inferior orbital fissure?
Inferior Ophthalmic division of Cranial Nerve V (V1)
What is the type of view that is shown?
Occipitomental veiw
What paranasal air sinuses can you see in this radiograph.
- Frontal*
- Maxillary*
- Ethmoid*
This makes the floor of the orbit weak.
Infraorbotal groove
What are the main contents of the orbit?
- Eye*
- Extrinsic ocular muscles*
- Ligaments supporting the eye*
- Optic, Oculomotor, Trochlear & Abducens* nerves
- Branches of Ophthalmic artery*
- The lacrimal (tear) apparatus*
- Orbital fat*
What are the components of the outer fibrous layer of the eye?
Cornea and sclera
It is a complete layer
What are the components of the middle vascular layer?
Ciliary body
Iris
Choroid
Is incomplete anteriorly. Anterior aperture (in iris) is called pupil
What are the components of the inner sensroy layer?
Retina
Is present posteriorly but anteriorly it stops short just in front of equator of the eye
What does the crystalline lens divide into?
The eye into an anterior and a posterior segment.
The watery fluid in the anterior segment
Aqueous humour
The gel in the posterior segment?
Vitreous humour
What part of the eye produces (secretes) aqueous humour?
Ciliary body
What are the intrinsic muscles of the eye?
Ciliaris
Sphincter pupillae
Dilator pupillae
What is the location, action and innervation of the ciliaris?
What is the location, action and innervation of the sphincter constrictor pupillae?
What is the location, action and innervation of the dilator pupillae?
What are eye movement produced by?
Extrinsic muscles of the eye
Basic ee movements
What is intort and extort?
These movements occur when the head is tilted- In order to keep the eyeballs focused on an object the eyes rotate in the opposite direction.
What is it called when the top of the eye rotates towards the nose?
Intort
What are the 6 muscles of the eye?
Four of these are straight course and two are oblique
the elevator of the upper eyelid is also considered as an extrinsic eye muscle even though it has no action on the eyeball itself. What is this muscle called?
Levator palpebrae superioris
What innervates the levator palpebrae superioris?
Oculomotor nerve
What are the functions of the medial rectus?
Adduction
What are the functions of the lateral rectus?
Abduction
What are the functions of the superior rectus?
Elevation
Adduction
Intorsion
What is the function of the inferior rectus?
Depression
Adduction
Extorsion
What is the function of the superior oblique muscles?
Depression
Intorion
Abduction
What is the function of the inferior oblqiue?
Elavtion
Extorsion
Abduction
Which is the only muscle that does not arise from the posterior aspect of the orbit?
Inferior oblqiue- Comes from inferior orbital fissure
Name the ligaments that prevent over-adduction and over-abduction of the eye.
Suspensory Ligament of eyeball – Lockwood’s Ligament
What is the function of the suspensory ligament of the eye
Support the eye & prevent downward displacement of the eyeball
Name the branch of the internal carotid artery that supplies the orbit and the eye.
Ophthalmic Artery
Which foramina in the orbit do the ophthalmic veins pass through to enter into the cavernous venous sinus in the cranial cavity?
Superior Orbital Fissure
In which part of the orbit does this structure lie, medial or lateral?
Lacrimal Gland is lateral – Lacrimal Sac etc. Medial
From which cranial nerve does parasympathetic innervation to this structure arise?
Facial nerve
Into which meatus of the nasal cavity does it drain (via the nasolacrimal duct)
Drains into the inferior nasal meatus
