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53 Cards in this Set

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Boundaries of Orbit
Roof: Orbital plate of frontal bone, lesser wing of sphenoid
Floor: maxilla, zygomatic bone, and orbital process of palatine.
Medial: Frontal process of maxilla, lacrimal bone, orbital plate of ethmoid, body of sphenoid
Lateral: Greater wing of sphenoid and frontal process of zygomatic.
7 Bones of orbit acronym
Spenoid - seven
frontal - funny
lacrimal - little
zygomatic - zebras
palatine - play
maxilla - music
ethmoid - easily
Contents of superior orbital fissure
-occulomotor nerve (CN 3)
-trochlear nerve (CN 4)
-Ophthalmic division of trigeminal (V1)
-Abducens Nerve (CN 6)
-Autonomic post ganglionic fibers on other nerves
-Superior Ophthalmic Vein
Location of superior orbital fissure
Between greater and lesser wing of sphenoid.
Contents of inferior orbital fissure
-Infraorbital Nerve (V2)
-Infraorbital Vessels
-Communication between inferior ophthalmic veins and pterygoid plexus of veins
-Infraorbital and zygomatic branches of V2 carry autonomic post ganglionic fibers
Trochlear Fossa
May just be a ridge not a fossa. Is the pivot point for the superior oblique muscle.
Infraorbital Foramen
Associated with canal and groove of same name. Nerves and blood vessels of the same name pass through it.
Fossa for lacrimal Sac
Between anterior and posterior Lacrimal crests
Layers of Eyelid
-Skin
-Subcutaneous tissue
-muscle layer
-tarsus plate
-conjunctiva
Palpebra
Eyelid
Skeleton of Eyelid
Acts as a partition between eyelid. Consists of Tarsal plates, medial and lateral palpebral ligaments, and orbital septum
Medial and Lateral Palpebral ligaments
Attach Tarsal plates to orbital bone.
Orbital Septum
Attaches to orbital rim, tarsal plates, and palpebral ligaments
Tarsal Glands
Brisles on the comb (Tarsal plate). Secrete oily liquid. Can get infected.
Canthus
Medial or lateral angles of palpebral fissure
Lacrimal Lake
Space at medial angle of palpebral fissure for tear accumulation.
Conjunctiva
When skin of eyelids reaches palpebral fissure, wraps around and coats eyelid from inside. Goes from epidermis to epithelial. 2 kinds:
Palpebral conjunctiva - coats inside of eyelid.
Bulbar conjunctiva - coats globe. Is continuation of palpebral after the conjunctival fornix
Conjunctival Fornix
Where conjunctiva leaves the eyelid, folds, and coats globe. Transition point from palpebral conjunctiva to bulbar conjunctiva.
Tarsal Plate
Acts as skeleton for eyelid allowing it to keep its shape. Flexible dense connective tissue.
Fascial Sheaths of Eyeball
Bulbar fascia
suspensory ligament - thickening of bulbar fascia under eyeball
Check ligaments - Expansion of Muscle sheaths to orbital wall
Superior Rectus Muscle
Origin: From common tendinous ring at apex.
Action: Elevates and Adducts Pupil
Innervation: Superior division of Occulomotor Nerve (CN 3)
Inferior Rectus Muscle
Origin: From common tendinous ring at apex.
Action: Depresses and Adducts Pupil
Innervation: Inferior division of Occulomotor Nerve (CN 3)
Lateral Rectus Muscle
Origin: From common tendinous ring at apex.
Action: Abducts pupil
Innervation: Abducens Nerve (CN 6)
Medial Rectus Muscle
Origin: Common tendinous ring at apex
Action: Adducts Pupil
Innervation: Inferior division of occulomotor nerve
Superior Oblique Muscle
Origin: Above and medial to tedonous ring.
Inserts: On sclera, passes through trochlear sling.
Action: Depress and Abduct pupil
Innervation: Trochlear Nerve (CN 4)
Inferior Oblique Muscle
Origin: Anterior, Inferior, and medial in orbit
Insert: Lateral aspect
Action: Abducts and Elevates Pupil
Innervation: Inferior division of occulomotor nerve (CN 3)
Levator Palpebrae Superioris Muscle
Origin: Above common tendinous ring
Inserts: Superior Tarsal Plate. Also attached to tarsal plate via superior tarsal muscle (smooth muscle)
Action: Elevates upper eyelid
Innervation: Superior division of occulomotor nerve (CN 3)
Superior Tarsal Muscle
Smooth muscle which connects levator palpebrae superioris to the tarsal plate. Is innervated by sympathetic nerves.
Partial v.s. Full ptosis
Partial ptosis - partial drooping of eyelid. Caused by loss of sympathetic innervation to superior tarsal muscle.
Full ptosis - Full drooping of upper eyelid. Caused by loss of occulomotor innervation to levator palpebrae superioris
Central Artery of Retina
Given off by ophthalimic artery when inferior to the optic nerve. Pierces optic nerve. Is only blood supply to retina therefore disruption = blindness. Runs with a vein of the same name.
Superior Ophthalmic Vein
Receives from supraorbital, facial, and inferior orbital veins and drains into the cavernous sinus. (No valves, therefore, bacteria can spread this way)
Inferior Ophthalmic Vein
Receives from infraorbital vein and from the pterygoid plexus of veins and drains into superior ophthalmic vein.
Lacrimal Gland
Divided into 2 parts by levator palpebrae superioris. Lacrimal duct drains gland into superior fornix. Stimulated by fibers from pterygopalatine ganglion which come via facial nerve.
Lacrimal Puncta
Hole in lacrimal papilla leading into lacrimal canaliculi.
Acronym for occular muscle innervation
LR6 SO4 Everything else by 3
Lacrimal Canaliculi
Small Canal entering into lacrimal sac
Lacrimal Sac
Upper expanded end of nasolacrimal duct where tears drain.
Nasolacrimal duct
Drains tears from lacrimal sac through inferior meatus of nasal cavity.
Horners syndrome
Sympathetics to head interrupted. Get a small pupil.
Optic Nerve
(CN 2) Special sensory for sight. From back of eyeball through optic foramen. Enclosed in a meningeal sheath; within sheath is central artery and vein of retina.
Occulomotor Nerve
Motor and parasympa. nerve.Enters orbit through orbital fissure and separates into superior and inferior divisions. Innervates most of occulomotor muscles. Also sends EGP fibers to cilliary ganglion.
Superior division of occulomotor nerve
(CN3)Innervates superior rectus and levator palpebrae superioris.
Inferior division of occulomotor nerve
(CN 3)Innervates medial rectus, inferior rectus, and inferior oblique muscles. Sends EGP to cilliary ganglion.
Long Cilliary Nerve
Branch off nasocilliary nerve (V1). Contains sensory fibers for orbit. Also has OGS from internal carotid plexus which dilate pupil.
Short Ciliary Nerve
Comes from cilliary ganglion. Receives sensory nerves from nasocilliary nerve, parasympathetic innervation from inferior branch of occulomotor, and sympathetic innervation (from somewhere). Does sensory for globe, innervates pupil, and is important for corneal reflex.
Trochlear Nerve
(CN 4) Motor. Enters obit through superior orbital fissue, innervates superior oblique muscle
Opthalmic Nerve
(V1) Sensory. Has 3 branches: Lacrimal, Frontal, and Nasocilliary.
Lacrmial Nerve
Branch of V1. Enters orbit through superior orbital fissure. Receives OGP from zygomatic nerve for lacrimal gland. Innervates lacrimal gland. Sensory to skin of upper eyelid.
Frontal Nerve
Largest branch of V1. Enters orbit through superior orbital fissure. Divides into supraorbital and supratrochlear nerves to supply skin.
Nasocilliary Nerve
Branch of V1. Enters orbit through superior orbital fissure passing through common tendinous ring. Gives off long cilliary nerve. Sends sensory fibers to eye via short and long ciliray nerves. Terminal branches are posterior ethmoidal, anterior ethmoidal, and infratrochlear nerve.
Abducens Nerve
(CN 6) Motor. Enters superior orbital fissure through common tendinous ring. Innervates lateral rectus muscle.
Things which pass through common tendinous ring.
-Occulomotor nerve (CN 3)
-Nasocilliary Nerve (V1)
-Abducens nerve (V6)
Things which pass/originate near common tendonous ring
-Superior oblique muscle (superior and medial)
-Levator palpebrae superioris (Superior)
-Trochlear Nerve (Outside)
-Lacrimal Nerve (Outside)
-Frontal Nerve (Outside)