2: Anatomy - orbit and eye Flashcards
What is the bony orbit?
Hole in the skull which the eyeball (globe) sits in
Which cranial bones make up the bony orbit?
Frontal bone
Maxilla
Zygoma
Sphenoid bone
Ethmoid bone
Lacrimal (a new one)
What are two important features of the frontal bone related to the bony orbit?
Orbital plate - the part of the frontal bone on the inside of the orbit
Supraorbital notch - or foramen, if it’s closed
What is an important feature of the maxilla in relation to the bony orbit?
Infraorbital foramen
Which important structures travel through the supraorbital and infraorbital notches?
Neurovascular bundles
What is an important feature of the sphenoid bone which transmits the optic nerve and blood vessels of the bony orbit?
Which feature of the sphenoid bone transmits other nerves and is found close to this structure?
Optic canal
Superior orbital fissure
What space is found inferior and lateral to the optic canal?
Which bone are it and the optic canal found in?
Superior orbital fissure
Sphenoid bone
The edges of the bony orbit are called ___.
margins
What are the superior, inferior, medial and lateral margins of the bony orbit collectively called?
Orbital rim
Where is the apex of the bony orbit found?
Optic canal
The apex of the bony orbit is slightly (medial / lateral).
medial
or nasal
The superior, inferior, medial and lateral margins are collectively known as the ___ ___.
orbital rim
How does the orbital rim protect the eye?
Anything larger in diameter than the orbital rim cannot make contact with the eye
So it protects the eye from direct trauma
Which is more anterior:
superior orbital margin
inferior orbital margin?
superior orbital margin
where your eyebrows sit
The orbital rim is fairly (thick / thin).
thin
What name is given to fractures of the medial and inferior orbital margins?
Orbital blowout fracture
What can be compromised by an orbital blowout fracture?
Inferior neurovascular bundle
e.g infraorbital nerve, a branch of CN V2 (maxillary division of trigeminal nerve)
causing a sensory deficit to maxillary skin
What would happen if CN V2 was damaged by an orbital blowout fracture?
Loss of sensation to maxillary region of skin
Which structure holds the eye in place and can be damaged by a zygoma fracture?
Suspensory ligament
Eye drops towards floor of orbit, causing diplopia (double vision)
Which circular muscle surrounds the eye and is responsible for closing the eyelids?
Orbicularis oculi
What is the function of the orbicularis oculi muscle?
Closes the eyelids
What are the two parts of the orbicularis oculi muscle?
Orbital (outer)
Palpebral (inner)
Which sheet of fascia connects the orbital rim to the eyelids?
Orbital septum
Which bits of fascia hold the shape of the upper and lower eyelids?
Superior tarsus and inferior tarsus
The tendon of which muscle attaches to the superior tarsus and helps to lift the superior eyelid?
Levator palpebrae superioris
Which muscles are responsible for
a) opening the superior eyelid
b) closing both eyelids?
a) Levator palpebrae superioris
b) Orbicularis oculi
Which ligaments hold the shape of the eye?
Medial palpebral ligament
Lateral palpebral ligament
Name the following structures:
a) Hold the shape of the superior and inferior eyelids (2)
b) Hold the general shape of the eye (2)
c) Extends as a sheet from the orbital rim to the eyelids (1)
d) Attaches to the superior eyelid and helps open it (1)
e) Closes both eyelids
a) Superior and inferior tarsus
b) Medial and lateral palpebral ligaments
c) Orbital septum
d) Tendon of levator palpebrae superioris
e) Orbicularis oculi
Name the important connective tissue structures of the eyelids.
Orbital septum
Superior and inferior tarsus
Tendon of levator palpebrae superioris
Medial and lateral palpebral ligaments
Which glands secrete lipids into the eye?
Tarsal glands
What is the purpose of the fluid secreted by the tarsal glands?
Stops the eyelids from sticking together
Which structures cover the
a) iris and pupil
b) sclera?
a) Cornea
b) Conjunctiva
Which structures are covered by the:
a) conjunctiva
b) cornea?
a) Sclera
b) Iris and pupil
The lacrimal gland is found in the superior and lateral part of the eye.
Where does lacrimal fluid drain?
Where exactly is it found?
Inferior lacrimal papilla
Inferior and medial part of the eye
Through which structure in the inferior lacrimal papilla does lacrimal fluid drain?
Lacrimal punctum
Lacrimal fluid is secreted from the ___ ___ and drains through the ___ ___ ___ via a small ___.
lacrimal gland
inferior lacrimal papilla
punctum
Which cranial nerve supplies the lacrimal glands?
Is it sympathetic or parasympathetic?
CN VII (Facial nerve)
Parasympathetic
Once lacrimal fluid has drained through the punctum of the inferior lacrimal papillae, which structures does it pass through?
Canaliculi
Lacrimal sac
Nasolacrimal duct…
The lacrimal gland is supplied by (sympathetic / parasympathetic) fibres of CN ___.
parasympathetic fibres of CN VII (Facial nerve)
What is the rough diameter of the eyeball in cm?
2.5 cm
Which structure is found in the centre of the iris?
Pupil
What is another name for the eyeball?
Globe