3.1 The Orbit and the Eye Flashcards
What are the 7 bones which form the Orbit?
- The Frontal Bone
- The Lesser Wing of the Sphenoid Bone
- The Greater Wing of the Sphenoid Bone
- The Zygomatic Bone
- The Maxilla
- The Lacrimal Bone
- The Ethmoid Bone
What are the 3 Foramina at the Apex of the Orbit?
- The Optic Foramen
- The Superior Orbital Fissure
- The Inferior Orbital Fissure
What passes through the Optic Foramen?
- The Optic Nerve
2. The Ophthalmic Artery
What passes through the Superior Orbital Fissure?
- The Occulomotor Nerve (Cranial Nerve III)
- The Trochlear Nerve (Cranial Nerve IV)
- The Abducens Nerve (Cranial Nerve VI)
- The Ophthalmic Division of the Trigeminal Nerve (Cranial Nerve V)
- Ophthalmic Veins
What passes through the Inferior Orbital Fissure?
The Maxillary Division of the Trigeminal Nerve (Cranial Nerve V)
Where do the Ethmoid Air Cells lie in relation to the Orbit?
Medially
Where do the Maxillary Sinus lie in relation to the Orbit?
Inferiorly
Where do the Frontal Sinus lie in relation to the Orbit?
Superomedially
What are the Main contents of the Orbit?
- The Eyeball
- Extrinsic Ocular Muscles
- Ligaments Supporting the Eye
- Cranial Nerves II, III, IV, V1, V2, VI
- Branches of the Ophthalmic Artery
- The Lacrimal (Tear) Apparatus
What are the 3 layers of the Eye?
- The Outer Fibrous Layer
- The Middle Vascular Layer
- The Inner Sensory Layer
What does the Outer Fibrous Layer of the Eye comprise of?
- The Opaque Sclera (5/6)
2. The Transparent Cornea (1/6)
What does the Middle Vascular Layer of the Eye comprise of?
- The Choroid
- The Ciliary Body
- The Iris
What does the Inner Sensory Layer of the Eye comprise of?
The Retina
Is the Outer Fibrous Layer of the Eye a complete layer?
Yes, It extends all of the way around the Eye
Is the Middle Vascular Layer of the Eye a complete layer?
No, it is incomplete anteriorly with an apperature in the Iris, known as the Pupil
Is the Inner Sensory Layer of the Eye a complete layer?
No, it is present posteriorly but anteriorly it stops just in front of the Equator of the Eye
What divides the Eye into an Anterior and a Posterior Segment?
The Crystalline Lens ( the lense itself is called crystalline lense)
What is the name given to the watery fluid in the Anterior Segment of the Eye?
Aqueous Humor
What is the name given to the gel in the Posterior Segment of the Eye?
Vitreous Humor
What is the significance of the Optic Nerve Head ( the optic disck)?
It is the blind spot of the eye
What is the significance of the Fovea Centralis?
It is the point where the “Cones” of the retina are most densely compact, so it is the point of best visison