Orbit Flashcards
This deck tests your knowledge of the orbit's anatomy. (14 cards)
What are the important exits in the orbit?
- Optic canal
- Superior orbital fissure
Draw out the skeletal relations of the orbit (frontal, ethmoid, and maxillary sinuses + nasal cavity).
Refer to Notion.
What are the extraocular muscles?
- Sup. / Inf. / Lat. / Med. Rectus
- Sup. / Inf. Oblique
What muscles elevate the eyelid?
- Levator palpebrae superioris
- Superior tarsal muscle (adjoins with LPS)
What does the lacrimal apparatus consist of?
- Lacrimal gland (orbital + palpebral part; palpebral part contains excretory ducts)
- Lacrimal sac (contains canaliculi)
- Nasolacrimal duct
Where does the nasolacrimal duct empty into?
Into nasal cavity, via inf. nasal meatus
What does the lacrimal apparatus do?
Tear production / drainage
What are the Meibomian glands, and where are they located?
- Modified sebaceous glands
- Located along rims of eyelid
What do the Meibomian glands do?
Produce meibum, an oily substance that prevents the eye’s tear film from evaporating
What is the conjunctiva?
A clear membrane that covers the sclera and the inside of the eyelids
What is the arterial supply of the eye?
Ophthalmic a.
What is an important ophthalmic a. branch?
Lacrimal a., which supplies lacrimal gland
What is the venous drainage of the eye?
- Sup. / Inf. ophthalmic veins, which drain into ophthalmic vein
- Ophthalmic vein drains into cavernous sinus
What cranial nerves innervate the orbit?
- CN II (sensory): visual info
- CN III (motor): all extra-ocular muscles except SO4 and LR6 + levator palpebrae superioris; parasympathetic motor innervation of ciliary muscles + sphincter pupillae muscles
- CN IV (motor): sup. oblique
- CN VI (motor): lateral rectus
