Orbit and Eye Flashcards
what is the entrance to the conjuctiva?
palpebral fissure
what are tarsal glands?
modified sebaceous glands behind the eyelashes that secrete an oily substance that prevents the overflow of tears
What bones make up then roof of orbit?
Frontal bone
What bones make up lateral wall of orbit?
Zygomatic bone
Greater wing of sphenoid
What bones make up the floor of the orbit?
Orbital plate of the maxilla
What makes up the medial wall of the orbit?
Frontal process of maxilla
Lacrimal bone
Orbital plate of ethmoid bone
Body of the sphenoid
What is the fibrous sheet that supports the eyelids?
Orbital septum
What does the orbital septum connect to?
The periosteum at the orbital margins
WHat do the orbital margins form?
Tarsal plates with tarsal glands
What are the two parts of the lacrimal gland?
Small palpebral part
Large orbital part
What ganglion is involved in lacrimal gland innervation?
Pterygopalantine ganglion
What nerves are involved with lacrimal gland innervation?
Fibers from lacrimal nucleus of c7 Greater petrosal n. Nerve of pterygoid canal Deep petrosal n. Zygomatic n. Lacrimal n.
What is the route of tears in the eye?
Lacus lacrimalis Lacrimal canaliculi Lacrimal sac Nasolacrimal duct Inferior meatus of nose
What sheaths is the optic nerve surrounded by?
Dura mater
Arachnoid
Pia
How does a change in cranial pressure affect the eyeball?
The cerebrospinal fluid surrounds optic nerve in subarachnoid space so a change presses on the nerve
What foramina does the trigeminal nerve go through?
Superior orbital fissure
What are the three branches of the ophthalmic division of trigeminal nerve?
Nasociliary
Frontal
Lacrimal
What does the frontal nerve ( division of trigeminal) divide into?
Supratrochlear and supraorbital
What fissure does the oculomotor come out of?
Superior orbital fissure
What does the superior branch of the oculomotor nerve supply?
Superior rectus
Levator palpebrae superioris muscle
What does the inferior branch of the oculomotor supply??
Inferior rectus
Middle rectus
Inferior oblique
What fissure do both the trochlear and the abducens nerve come out of?
Superior orbital fissure
What is the function of the branches of the nasociliary nerve?
Communicating branch to ciliary ganglion
Ciliary nerves with sympathetic fibers
What are the two branches of the nasociliary nerve?
Anterior ethmoidal
Infra trochlear
What foramen does the anterior ethmoidal nerve pass through?
Anterior ethmoidal foramen
What is the opthalmic artery a branch of?
internal carotid artery
what are the branches of the opthalmic artery?
ciliary arteries central artery of the retina muscular branches lacrimal artery supratrochlear artery supraorbital artery
what are the 2 main opthalmic veins?
inferior ophthalmic vein
superior opthalmic vein
where do both opthalmic veins drain that can serve as a route of infection?
backward into the cavernous sinus
what type of ganglion in the ciliary ganglion?
parasympathetic
what nerve do the preganglionic parasympathetic fibers for the ciliary ganglion come from?
oculomotor nerve
what nerve do the postganglionic fibers of the ciliary ganglion travel through?
short ciliary ganglion
which muscle fibers control the dilator pupillae of the eye?
postganglionic sympathetic (from ciliary ganglion)
what fibers control the sphincter pupillae of the eye?
postganglionic parasympathetic (from ciliary ganglion)
what needs to happen in the eye for distant vision to occur?
ciliary muscle relaxed
fibers under tension
lens is stretched
what needs to happen in the eye for near vision to occur?
parasympathetics cause ciliary muscle to contract
fibers relax
lens relaxes
what are the 6 main optic muscles?
middle rectus inferior rectus superior rectus lateral rectus superior oblique levator palpebrae superioris
what are the 2 parts of the lacrimal gland?
Large orbital part
Small palpebral part
