Anatomy - Orbit Flashcards
What bones form the roof and floor of the orbit?
Floor
- orbital process of maxilla
- palatine bone
Roof
-orbital part of frontal bone
What bones form the walls of the orbit?
Medial walls
- Orbital plate of ethmoid
- Frontal process of maxilla
- Lacrimal
- Sphenoid
Lateral walls
- frontal process of zygomatic bone (ant)
- greater wing of sphenoid (post)
The apex of the orbit is at the __
Optic canal in the lesser wing of the sphenoid
What separates the floor of the orbit from the lateral wall?
Inferior orbital fissure
What houses the lacrimal gland?
Fossa for the lacrimal gland in the orbital part of the frontal bone
Fissures and foramina of the orbit
- Optic canal
- Superior orbital fissure
- Inferior orbital fissure
- Infraorbital groove
- Ethmoidal foramina
The optic canal goes through ___ and allows for passage of ___
Goes through the lesser wing of the sphenoid
Allows for passage of
Optic n. (CN II)
Ophthalmic a.
Superior orbital fissure is located ___ and allows for passage of ___
Between the greater and lesser wings of sphenoid
Allows for passage of: CN III IV VI V1 Ophthalmic v.
Inferior orbital fissure is located ___ and allows for passage of ___
At the right angle to the superior orbital fissure
-between greater wing of sphenoid and maxilla
Allows for passage of CN V2 (maxillary n.) Infraorbital vessels
Travel of the infraorbital groove?
What does it contain?
Begins from inferior orbital fissure Travels anteriorly Becomes enclosed in bone Forms infraorbital canal Opens below orbital rim as the infraorbital foramen
Contains infraorbital n. and vessels
Ethmoidal foramina allows for passage of __
Anterior and posterior ethmoidal nerves and vessels
____ humor is irreplaceable and more dense than ___
Vitreous
Aqueous
The aqueous humor is located in the (anterior/posterior) chamber of the eye
Anterior
Which is between cornea and iris
The posterior chamber is located between ___ and ___
Iris and lens
3 layers of the eyeball and what they contain
- Fibrous
- sclera, cornea
- Vascular
- choroid, ciliary body, iris
- Retinal
- optic disc, macula, ocular fundus
Tough fibrous layer covering the posterior 80% of the eyeball.
The anterior part is visible as the white of the eye
Sclera
Transparent part of the fibrous layer located in the anterior part of the eye.
Cornea
The cornea is more ___ than the sclera and projects ___
Convex
Anteriorly
Blinking and tears are elicited by touching what? and innervation of what nerve?
Cornea
Ophthalmic n. (V1)
The ____ lines most of the sclera and contains a rich capillary bed, with the smallest vessels located next to the ___, which is avascular
Choroid
Retina
The ____ connects the choroid with the iris. It is both ___ and ___
Ciliary body
Muscular
Vascular
The ___ is a thin contractile diaphragm with a central aperture, the ___, for transmitting ___.
Iris
Pupil
Light
Two involuntary muscles control the size of the pupil:
- system
- fibers
- action
- speed
Sphincter pupillae
- parasympathetic
- circular fibers
- constriction
- fast
Dilator pupillae
- sympathetic
- radial fibers
- dilation
- slow
The optic part of the retina consists of 2 layers:
- Neural layer
- light sensitive
- continuation of the CN II - Pigmented layer
- attached to choroid
- helps reduce scattering of light through absorption
During a retinal detachment, which layer of the retina becomes dislodged?
Neural layer only
Where the Optic Nerve (CN II) enters the eyeball, the retina contains the __
Optic disc
True or false:
the optic disc has photoreceptors
False
The oval-shaped area of acute vision is called the __
Macula
The posterior part of the eyeball wig its retina is called the ____.
This is where light is ___
Ocular fundus
Focused
Light traveling to the retina passes through the following structures:
Cornea Anterior chamber Posterior chamber Lens Vitreous humor
The anterior chamber is filled with ___, which is produced by ___
Aqueous humor
Ciliary body