1:2. Orbit and the Eye Anatomy Flashcards Preview

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Flashcards in 1:2. Orbit and the Eye Anatomy Deck (67)
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Name the bones (not the labels)

Beige = Frontal

Blue = Zygomatic

Purple = Maxilla

Red = Sphenoid

Yellow = Ethmoid

Dark Blue = Lacrimal

Green = Nasal


Name the labels (not the bones)

A --> F

A = Superior Orbital Fissue

B = Optic Canal 

C = Orbital Plate of the Frontal Bone 

D = Supraorbital Notch/Foramen

E = Orbital Plate of Ethmoid

F = Infraorbital Foramen


Name all the same labels on this skull?

Superior Orbital Fissure

Optic Canal

Orbital Plate of the Frontal Bone

Orbital Plate of the Ethmoid Bone

Supraorbital Notch

Infraorbital Foramen


Difference between a foramen and a notch?

Foramen is a complete circle

Notch is uncomplete - like a C shape


The bony orbit is described as a four sided pyramid

The apex is the orbital canal

What does the base make up?

What is it composed of?

The base makes up the orbital rim

Composed of superior, inferior, medial and lateral orbital margins


How is the eye protected from a direct blow?

Orbital Margins - superior orbital margin is further forward than inferior so eye is protected


Orbital rim - nothing bigger than the orbital rim will come into contact with the actual eye



Describe orbital blowout fractures?

The medial wall and orbit floor are very thin

In trauma, the orbital margins and rim don't fracture as they are strong

The medial wall and floor are very thin though and can break

Can cause an orbital blowout fracture


Complications of orbital blowout fracture?

Orbital contents can become trapped

Infraorbital neurovascular bundle can be damaged


If the infraorbital neurovascular bundle was damaged in a blowout fracture, what would happen?

Loss of sensation to face


The external eyelid is split into two parts:

Name them

Identify them

Orbital Part

Palpebral Part

X = Palpebral

Y = Orbital


Name the muscle that surronds the eye in the external layer?

Obicularis Oculi


What is the orbital septum?

This is a sheet of fascia below the eyelid

Found in the middle layer

This separates the superficial part of the eye from the deep part to prevent the spread of infection


Label these parts of the eyelid

Which layer is this?


A = Orbital Septum

B = Inferior Tarsus

C = Medial Palpebral Ligament

D = Superior Tarsus

E = Tendon of Levator Palpebrae Superioris

F = Lateral Palpebral Ligmanent


Internal Layer


What is the Tarsal gland?

Where is it found?

These secrete an oily/waxy substance that prevents the eyelids from sticking together and prevents tears from overflowing and streaming constantly


Found in the tarsal plates of the tarsi


Describe the Tarsi?

Found above and below the eye

Plates of fibrous connective tissue that give the eyelid its half moon shape

Give protection to eye and attachment for muscles


Where does the Levator Palpebrae superioris attach?

The superior Tarsi


Name the surface anatomy of the eye

A = Location of the lacrimal duct

B = Pupil

C = Blood Vessel (Conjuctival vessel)

D = Lacrimal Lake

E = Puncta

F = Lower eyelid, lined with Conjuctiva

G= Conjunctival Fornix

H = Sclera, covered by conjuctiva

I = Limbus/Corneoscleral Junction


What innervates the lacrimal gland?

CN VII (Facial Nerve) 



Describe how the lacrimal apparatus works?

CN VII Parasympathetic innervation

Lacrimal gland produces lacrimal fluid

Washes across eye

Collects in lacrimal lake

Drains out of Puncta

Drains into lacrimal sac

Drains along nasolacrimal duct

Eventually reaches inferior meatus


Where does the lacrimal fluid end?

Inferior Meatus


Coloured bit in the centre of the eye?

Black bit in the very centre of the eye?

White bit in the eye?

Clear, transparent bit that covers the coloured bit?







What control is the pupil under?



Describe the layers of the eye?

Fibrous, Outer Part

Uvea = Middle Layer

Retina (Inner Layer)


Describe the outer layer of the eye

Tough and fibrous

Composed of two parts

Sclera - the white part where extra-ocular muscles attach. Makes up about 5/6ths of the eye


Cornea = Clear, colourless, front of the eye. Makes up most of the refractive power - the ability to focus light


Describe the middle layer of the eye

The Uvea

This is the vascular layer

Has three parts:

- Iris 

- Ciliary Body 

- Choroid


Describe the function of the three parts of the middle layer of the eye (the uvea)

Iris = Changes size of pupil

Ciliary Body = Attaches to iris. Changes shape of lens and secretes aqueous humour

Choroid = Provides nutrition and gas exchange 


Describe the inner layer of the eye?

This is photosensitive


- Retina

- Macula

- Optic Disc


Describe the segments of the eye?

- Names?

- Where is the divide?

- Humour?

Dividied into anterior and posterior

LENS is the borders

Anterior = In front of Lens

Posterior = Behind lens


Anterior = Aqueous Humour

Posterior = Vitreous Humour


Describe the anterior segment of the eye?

Divided into two chambers - anterior and posterior

Anterior: Between cornea and iris

Posterior: Between iris and suspensory ligaments

Both contain aqueous humour


Describe the posterior segment of the eye?

This is everything found behind the lens (2/3rds of the eye)

Contains vitrous body which contains vitreous humour

Vitreous humour is gel like

Vitrous humour holds the lens and the choroid against the sclera