Test 2 Flashcards
Bones of the roof of the orbit
Orbital plate of frontal bone
Lesser wing of sphenoid
Bones of the lateral wall of the orbit
Frontal process of zygomatic
zygomatic process of frontal
Greater wing of sphenoid
Bones of the floor of the orbit
Maxilla (orbital surface)
Palatine (orbital process)
Zygomatic (orbital plate)
Bones of the medial wall of the orbit
Maxilla (frontal process)
Lacrimal
Ethmoid (orbital plate)
Lesser wing of sphenoid
What are the margins of the orbit?
Supraorbital margin (frontal bone)
Infraorbital margin (maxilla and zygomatic)
Foramen, grooves and fissures of the orbit
Supraorbital foramen
Infraorbital groove
Optic foramen
Superior orbital fissure
Inferior orbital fissure
Nasolacrimal fossa
Infraorbital groove
Travels into infraorbital canal where it exits as infraorbital foramen
Infraorbital nerve, arteries and veins travel through it
What goes through the superior orbital fissure?
Oculomotor
Trochlear
Branches of opthalamic division of trigeminal
Abducens
Sympathetic roots of ciliary ganglion
Inferior orbital fissure
Separates greater wing of sphenoid from palatine, maxilla and zygomatic bones
Nasolacrimal fossa
Deep concavity within lacrimal bone that harbours lacrimal sac which drains tears into inferior meatus of nose
Three layers of the wall of the eyeball
- Fibrous layer (outer)
- Vascular layer (middle)
- Retina (inner)
Parts of the fibrous layer of the eyeball
- Sclera: white opaque coat of dense collagenous CT that gives eye shape, protects internal parts and is an attachment site for extraocular eye muscles
- Cornea: avascular, transparent; superficial to iris and allows light to enter
Scleral venous sinus (canal of Schlem)
A channel at the junction of cornea and sclera for drainage of aqueous fluid
Parts of the vascular layer of the eyeball
- Choroid: posterior, dark brown portion that lines internal surface of sclera; blood supply nourishes retina and melanin absorbs stray light rays
- Ciliary body: dark brown anterior portion; consists of ciliary processes and ciliary muscles
- Iris: coloured portion btwn cornea and retina
Ciliary processes
Part of ciliary body of vascular layer of eyeball; folds on inner surface that secrete aqueous humour and attach zonular fibres to the lens
Ciliary muscles
Part of ciliary body of vascular layer of eyeball; smooth muscle tissue encircling the lens that allow adaption to near or far sighted vision via contracting and relaxing
Smooth muscle layers of iris
- Spinchter pupillae muscles (circulare muscles): constrict pupil vis parasympathetic function
- Dilator pupillae (radial muscles): dilate pupil via sympathetic function (superior cervical ganglion)
**regulate light entering eyeball
Optic disc
Site of exit of optic nerve; central retinal vein and artery bundled w it
Two major portions of the retina
- Pigmented layer: contains melanin which helps choroid absorb stray light rays
- Inner neural(sensory) layer: contains photoreceptors
Three layers of retinal neurons in neural layer
- Photoreceptor cell layer: contains rods and cones
- Bipolar cell layer: horizontal and amacrine cells that modify signals from photoreceptors to bipolar ganglion cells
- Ganglion cell layer: contains optic nerve axons
Rods and Cones
Rods: vision of shades of grey; periphery
Cones: colour vision in bright light; in fovea centralis
Macula
Centre of retina; contains fovea centralis
Fovea centralis
small depression in macula containing cones; area of highest visual resolution (sharpness of vision)
Lens
Clear, transparent, avascular, refractive bioconvex disc structure located posterior to iris and pupil