11-orbit brainscape Flashcards by Juan C

1) Lacrimal canaliculus 2) Lacrimal sac 3) Nasolacrimal duct 4) Lacrimal puncta 5) Lacrimal gland 6) Tendon of levator palpebrae superioris muscle

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1) Superior Oblique 2) Supratrochlear 3) Supraorbital 4) Levator palepebrae superior 5) Superior rectus 6) Lacrimal gland 7) Lateral rectus 8) Lacrimal nerve 9) Frontal 10) Trochlear 11) V1 12) Medial Rectus

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Abductors of the Eye

Lateral Rectus Superior Oblique Inferior Oblique

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Adductors of the eye

Medial Rectus Inferior Rectus Superior Rectus

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Bones of the Orbit

1) Frontal 2) Optic Canal 3) Ethmoidal Foramina 4) Ethmoid Bone 5) Lacrimal Groove 6) Ethmoid Bone 7) Palatine Bone 8) Maxilla 9) Inferior orbital fissure 10) Zygomatic bone 11) Greater wing of sphenoid 12) Superior orbital fissure 13) Lesser Wing of Sphenoid

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Chalazion

Inflamed tarsal glands

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Conjunctival sac

potential space between eyeball & eyelides

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Consequence of pushing an object through the floor of the obrit

Entrance into the maxillary sinus

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Consequence of pushing an object through the medial wall of the obrit

Entrance into the ethmoidal sinus

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Conseuqnece of pushing an object in an anterior to posterior direction of the obrit

Middle Cranial fossa

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Cornea vs sclera

Cornea= transparent anterior 1/6 coat of eyebal Sclera= whitish, opaque, posterior 5/6 of the outer coat of eyeball

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Course of the Oculomotor Nerve to the Eye

1) Through lateral wall of the cavernous sinus then through superior orbital fissure 2) Divides into superior & inferior branches before entering the orbit

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Depressors of the Eye

Inferior Rectus Superior Oblique

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Effect of lesion of CN VII on eye

orbicularis oculi cannot close eyelid fully, so protective rapid blinking may be lost

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Elevators of the Eye

Superior Rectus Inferior Oblique

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Esotropia

inward deviation of the eyes

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Exophthalmos

protrusion of eyeball - can occur due to a “blow out” fracture (damage of the thin medial wall) or due to tumors

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Exotropia

outward deviation of the eyes

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Heterophoria

latent tendency for eyes to deviate

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Heterotropia

misalignment of eyes is manifest

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Hyperemia in the eyes

bloodshot, vessels are dilated

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Hypertropia/Hypotropia of the eyes

Hyper= upward deviation, Hypo= downward deviation

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Iris

colored diaphragm seen through cornea

Lateral & medial angle (canthi) of the eye

angles of the palpebral commisure

Lateral Rotators (extorsion) of the eye

Superior Rectus Inferior Rectus

Lesion of CN IV

Should not be able to look inferiorly when eye is adducted

Lesion of VI

Cannot abduct the eye

Lining of the bones of the orbital cavity

Periorbita - continuous with dura mater at the optic canal & superior orbital fissure

Medial Rotators (intorsion) of the eye

Superior Oblique Inferior Oblique

Orbital Septum & Clinical Correlate

Fibrous membrane from the orbital margin to the tarsus, continuous with pericranium \*Fire wall that prevents spread of infection from superior fascia of eyelid to the interior of the orbit

Order of drainage of the lacrimal gland to the nose

1) Lacrimal gland 2) Lacrimal lacrimalis (depression in eye that collects fluid) 3) Lacrimal papilla (projection on each eyelid) 4) Lacrimal punctum (opening on the papilla) 5) Lacrimal canaliculus - duct that drains from punctum 6) Lacrimal sac 7) Nasolacrimal duct

Orthophoria

exact ocular balance

Palpebral Comissure

Unites eyelids medially & laterally

Palpebral conjunctiva:

mucosa covering posterior surface of eyelid: turns back on itself at the superior and inferior conjunctival fornices, where it becomes continuous with the bulbar conjunctiva

Palpebral fissure

opening between lids

Pupil

aperture at center of iris

Sensory/Motor Limbs of the Blink (Corneal) Reflex

Afferent: CN V1 Efferent: CN VII (via orbicularis oculi muscle)

Structure of the optic nerve

not actually a nerve, it is an extension of the brain covered by meninges

Structure of the Orbit:

Medial walls are parallel, 25 mm apart Lateral walls are at right angles Length of both walls= 50 mm Eyeball is 25 mm long, half as long as orbit

Structures that are found on the level of the orbits on an axial CT/MRI

\*Ethmoidal sinus laterally \*Sphenoid sinus posteriorly \*Foramen spinosum, carotid canal, foramen ovale, jugular foramen, foramen magnum, crita galli/cribiform plate

Sty

ciliary gland duct is blocked

Tarsal gland

modified sebaceoius glands within a tarsus \*Oily secretion forms surface film to reduce evaporation of tears

Tarsal muscles

smooth muscle within tendon of the leavator palpebrae superioris \*attaches tarsus to the upper eyelid \*Sympathetic innervation from internal carotid plexus--\> elevate eyelid

Tarsus

Semilunar plate of dence CT between the palpebral conjunctiva and the superficial fascia

Testing the Inferior Oblique

Look medially and up

Testing the Inferior Rectus

Look laterally and down

Testing the Superior Oblique

Look medially and down

Testing the Superior Rectus

Look laterally and up

Through which opening will a tumor of the middle cranial fossa enter the orbit from?

The superior orbital fissure

Through which opening will a tumor of the temporal or infratemporal fossa enter the orbit from?

Inferior orbital fissure

What are the bony boundaries of the optic canal?

Between the lesser wing and body of sphenoid

What are the bony boundaries of the superior orbital fissure?

Between the greater and lesser wings of sphenoid

What is the affect on the eye of a tumor in the ethmoid and sphenoid sinuses?

erosion of the ethmoid and sphenoid bones and affect the optic nerve

What is the communication between opthalamic vessels & arteries/veins of the face?

The superior opthalamic vein enters into the cavernous sinus (inferior opthalamic empties into pterygoid venous plexus) and communicate with the facial and supraorbital veins anteriorly --\> can get meningitis this way

What is the consequence of pushing an object through the roof of the orbit?

It will enter the anterior cranial fossa

Where should a patient look when a surgeon is trying to enter the orbit?

laterally- gives more room