Orbit, eyelids, conjunctiva, lacrimal apparatus (dave's notes) Flashcards
Describe the orbit
A boney cavity shaped like a pyramid with the base facing anteriorly
What forms the medial wall of the orbit? What does this enclose? What is at the top of the medial wall?
The anterior lacrimal crest, across the lacrimal bone (thus enclosing the lacrimal sac). At the top is the A/P?? ethmoidal foramina
What is the lateral wall composed of? What else is found here? What spaces are communicated with?
Largely the zygomatic bone with the superior orbital fissure posterior at the top and the inferior orbital fissure extending from the superior orbital fissure leading into the pterygopalatine and infratemporal fossae.
What would happen if the lateral wall of the orbit continued?
It slopes away at 45’, and if prolonged would meet at the pituitary fossa.
What does the floor of the orbit consist of?
The orbital surface of the maxilla
Describe the orbital margin
Four curved sides
What covers the eyelids?
Loose skin anteriorly and adherent conjunctiva posteriorly, which is attached to the orbital septum.
What occurs to the lateral parts of the conjunctiva?
?It thickens laterally to form the tarsal plates?
Describe the tarsal plates ??
Crescent shaped, curving around the eyeball.
What is found at the medial end of each lid?
The lacrimal papilla and punctum, leading to the canaliculus of the lacrimal sac
Describe the conjunctiva
A transparent membrane attached to the sclera, reflected to the inner parts of the eyelids
What is the lacrimal gland?
A serous gland with a large orbital part and a small palpebral part.
How many ducts does the lacrimal gland have? Where do they lead?
Approximately 12 ducts leading to the superior fornix
Where is the large orbital part of the lacrimal gland found?
In the lacrimal fossa
What is the nerve supply to the lacrimal gland?
Secretomotor fibres from the superior salivatory nucleus travel on the greater petrosal nerve to the pterygopalatine ganglion to the zygomatic nerve.
