Orbit Flashcards
What are the superior and inferior fornices?
Where the bulbar and palpebral conjunctiva meet
What are the two conjunctiva of the eye and what do they cover?
. Palpebral conjunctiva
. Bulbar conjunctiva
. palpebral part covers inside of eyelids and bulbar part covers the sclera and cornea
What is the plica semilunaris?
Medial fold of conjunctiva near the lacrimal lake
What is the iris and where is it found?
. It is a contractile diaphragm
. It lies on the anterior surface of the lens
What is the pupil and which muscles control the diameter?
. The pupil allows for the transmission of light
. Sphincter pupillae and dilator pupillae
What are the tarsal plates?
. Dense bands of CT that strengthen the eyelids
. There are superior and inferior tarsal plates
What are the medial and lateral palpebral ligaments?
They connect the superior/inferior tarsal plates to the medial/lateral angels of the eye
What is the orbital septum?
Weak membrane that spans from the tarsal plates to the margins of the orbit and becomes continuous with the periosteum
What are the 5 layers of the eyelid?
. Skin . Subcutaneous . Muscular (orbicularis oculi, levator palpebrae superioris) . Tarsofacial (tarsal glands and plate) . Conjunctival (palpebral conjunctiva)
The lacrimal gland is split into two parts (which parts) by what structure?
. Levator palpebrae superioris
. Superior (orbital)
. Inferior (palpebral)
What type of fibers is the lacrimal gland stimulated by, and where do they originate from?
Para/post fibers from the pterygopalatine ganglion (PPG)
Describe the innervation of the lacrimal gland.
Superior salivatory nucleus gives off VE para/pre fibers that run through the greater petrosal nerve (has ss-taste from soft palate) of CN VII. The greater petrosal nerve meets up with the deep petrosal nerve (sym/post) to make the vidian nerve. The vidian nerve then goes to the PPG, where para/pre fibers synapse. From the PPG, the para/post fibers run through the pterygopalatine nerve to V2 to zygomatic nerve (branch of V2) to communicating branch to lacrimal nerve (branch of V1) to the lacrimal gland
Describe the course of tear drainage
Lacrimal gland to lacrimal ducts to superior/inferior fornices… then tears collect at the lacrimal lake and then drain through the lacrimal punctum on the lacrimal papilla. They then go through the lacrimal canaliculi to the lacrimal sac, which leads to the nasolacrimal duct and the nasal cavity
Where is the lacrimal caruncle?
Small mound of modified skin tissue in the lacrimal lake
Bones forming the orbit are lined with ________, which forms the _____________ of the eyeball.
Periorbita, fascial sheath
Where does the fascial (bulbar) sheath course on the actual eyeball?
Optic nerve to the corneoscleral junction
Expansions of the fascial sheath at the medial and lateral rectus muscles are called:
Medial and lateral check ligaments
What is the suspensory ligament of the eye?
Blending of the medial/lateral check ligaments with the fascia of the inferior rectus and inferior oblique
What is the tubular sheath?
The fascial sheath is pierced by the extraocular muscle tendons and is reflected onto each of them as the tubular sheath
All of the extraocular muscles are innervated by _______ except?
CN III, superior oblique (CN IV) and lateral rectus (CN VI)
The fovea is _________ to the optic disc (blind spot)
lateral
What are the three axes of rotation of the eyeball?
. Anteroposterior
. Vertical
. Horizontal
Which two muscles are responsible for elevating the eyeball? What axis of rotation is this?
. Superior rectus
. Inferior oblique
. Horizontal axis
Which two muscles are responsible for depressing the eyeball? What axis of movement is this?
. Inferior rectus
. Superior oblique
. Horizontal axis
Which three muscles abduct the eye and what axis of movement is this?
. Lateral rectus
. Superior oblique
. Inferior oblique
. Vertical axis
Which three muscles adduct the eye? What axis of movement is this?
. Medial rectus
. Superior rectus
. Inferior rectus
. Vertical axis