Week 1 - A - Anatomy of the orbit and eye Flashcards
What bone forms the inferolateral margin of the orbital?
The zygomatic bone
What bone forms the superior margin of the orbit?
The frontal bone
What bone forms the inferiormedial margin of the orbit?
The maxillary bone
From medial t lateral state the bones So the: blue, yellow then pink
Blue bone - lacrimal bone Yellow - ehtmoid bone Pink - sphenoid bone
What is the hole in sphenoid bone? - lying immediately lateral to the ethmoid bone
This is for the optic canal
The ethmoid air cells (sinus) lie behind the ethmoid bone, where does the ethmoid sinus drain? (remember the ethmoid air cells have a posterior, anterior and middle)
Posterior ethmoidal air cells - superior meatus Anterior ethmoidal air cells - semilunar hiatus of middle meatus Middle ethmoidal air cells - ethmoidal bulla of middle meatus
thin, semitransparent mucous membrane that covers the posterior surface of the eyelids and is then reflected onto the eyeball
This is the conjuctivae It is non-keratinized stratified columnar epithelium with goblet cells
What is the foramina just below the orbit in the maxillary bone? What nerve passes through here that provides sensory innervation to the skin of the lower eyelid, side of the nose, moveable part of nasal septum, anterior cheek and upper lip?
The infra-orbital foramen The ifra-orbital branch of the maxillary division of the trigeminal nerve passes through here
The eyelids contain glands which secrete an oily substance to stop the evaporation of tears What is this substance known as
Meibum Produced by the tarsal glands (aka the meibomian glands)
The arrows pointing towards the yellw and green in the middle of the picture are what?
Pointing towards yellow - the tarsal gland (meibomian gland) produces meibum Pointing towards green - tarsal plate
What is the function of the tarsal plate?
Contributes towards support of the eyelid
What muscles are responsible for the movements of the eyeball and superior eyelid?
The extra-ocular muscles
What muscles causes elevation of the upper eyelid?
The levator palpabrae superioris
What is the concentric muscle of facial expression? (supplied by CN VII) What is its function?
The orbicularis oculi Closes the eylid when contracting and sweeps tears across the eyeball and on its way to drainage via the punctum
What glands produce tears? Where are they situated?
Lacrimal gland - situated int he superiolateral region of the orbit
What is the function of tears?
Tears lubricate the eyes and capture dirt and then drain them into the nasal cavity
After tears are produced and travel across the cornea (helped by orbicularis oculi moving the eyelid), how do they travel to the nasolacrimal duct?
Tears are produced by lacrimal gland then go to - cornea - then through the lacrimal punctum to the lacrimal canaliculi (superior and inferior) - the lacrima canaliculi connects to the lacrimal sac which connects to the nasolacrimal duct
Where does the nasolacrimal duct drain?
Drains into the inferior meatus on the lateral wall of the nasal cavity
What nerve supplies the lacrimal gland?
The greater petrosal nerve - branch of the facial nerve (CN VII)
Are glands usually supplied by sympathetic or parasympathetic? What are the parasympathetic cranial nerves?
Usually by parasympathetic apart from the sweat glands which are sympathetic CN III - oculomotor nerve CN VII - facial nerve CN IX - glossopharngeal nerve CN X - vagus nerve