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83 Cards in this Set
- Front
- Back
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study osteology of orbit
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study osteology of orbit
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7 bones of the orbit
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frontal, zygomatic, maxillary, palatine, lacrimal, sphenoid, ethmoid
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what four openings are found on the posterior orbit?
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optic canal, superior orbital fissure, ethmoid foramina, and inferior orbital fissure
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what passes through the optic canal?
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optic nerve (CN II) and ophthalmic artery
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what passes through the superior orbital fissure?
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CN III, IV, V1, VI
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what passes through the inferior orbital fissure?
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infraorbital nerve and vessels
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what passes through the ethmoidal foramina?
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anterior/posterior ethmoidal nerves and vessels
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what causes a blow-out fracture of orbit?
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striking impact on eyeball
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what is conjunctiva?
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thin membrane covering inner eyelid
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where are meibomian glands found?
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tarsus of the eyelid
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what is the frontal nerve a branch of?
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V1
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where is the trigeminal ganglion found?
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Meckel's cave
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where are symptoms of Herpes Zoster typically found?
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along the V1 division of the Trigeminal Nerve
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what is the lacrimal nerve a branch of?
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V1
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parasympathetic innervation of lacrimal gland (stimulation of tears)
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VII-->greater petrosal nerve of VII-->Pterygoid canal-->pterygopalatine ganglion-->zygomaticotemporal nerve of V2-->Lacrimal nerve of V1-->Lacrimal gland
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what is the nasociliary nerve a branch of?
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V1
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what are the 3 direct branches of V1?
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frontal, lacrimal, and nasociliary nerves
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what are the 2 branches from the frontal nerve?
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supraorbital and supratrochlear nerve
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what are the 6 branches of the nasociliary nerve?
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long ciliary nerves, short ciliary nerves, posterior ethmoidal nerve, infratrochlear nerve, anterior ethmoidal nerve, external nasal nerve
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what do the ciliary branches of the nasociliary nerve innervate?
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sensory to cornea
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what does the supraorbital nerve (from frontal nerve) innerate?
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sensation to frontal scalp skin
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origin of optic nerve?
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lateral geniculate body
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components of optic nerve (CN II)?
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special sensory
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what is the only ganglion of the optic nerve (CN II)?
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in retina
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what three eye movements compose incyclotorsion?
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depression, abduction, and medial rotation?
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what three eye movements compose excyclotorsion?
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almost the opposite of incyclotorsion: elevation, abduction, lateral rotation
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which muscle abducts the eye? adduct?
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lateral rectus, and medial rectus respectively.
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how does the superior rectus act on the eye?
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elevation and some adduction.
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how to test superior rectus muscle?
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look lateral and up
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action of inferior oblique on the eye?
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elevation and some abduction
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how to test inferior oblique muscle?
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look medially and upward
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what two muscles act together to create pure elevation?
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superior rectus and inferior oblique
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what is the action of the inferior rectus on the eye?
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depression and some adduction
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how to test inferior rectus?
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look laterally and downward
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which two muscles act together to create pure depression?
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inferior rectus and superior oblique
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action of the superior oblique on the eye?
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depression and some abduction
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how to test superior oblique?
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look medially and downward
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which eye muscle utilizes a trochlea (pulley)?
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superior oblique
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which muscle creates incyclotorsion? excyclotorsion?
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superior oblique, and inferior oblique respectively
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other name for CN III?
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oculomotor
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what are the two divisions of CN III?
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superior and inferior
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what two muscles does the superior division of CN III innervate?
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levator palpebrae superior and superior rectus
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which division of CN III sends parasympathetic fibers to the ciliary ganglion?
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inferior division of CN III
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what types of fibers does III carry?
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visceral motor (para) and somatic motor
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what two smooth muscles does CN III innervate?
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ciliary body and sphincter pupillae
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where do sympathetic fibers going to the head generally synapse?
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superior cervical ganglion
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how do postganglionic sympathetic nerve fibers typically reach their destinations in the head?
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travel along the internal carotid then "piggyback" on cranial nerves
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three symptoms of horner syndrome?
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ptosis, anhydrosis, miosis
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what is miosis?
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constriction of pupil
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what causes Horner syndrome?
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interruption of a cervical sympathetic trunk
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what are 3 possible locations of the sympathetic interruption with regards to Horner syndrome?
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1. CNS
2. Pre-ganglionic neuron 3. Post-ganglionic neuron |
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what is CN IV? what does it innervate?
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trochlear nerve innervates superior oblique muscle
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what opening in the orbit does CN IV travel through?
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superior orbital fissure
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what is the course of CN IV?
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middle cranial fossa, cavernous sinus, superior orbital fissure
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what type of fiber is carried by CN IV?
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somatic motor
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does CN IV have a ganglion?
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NO
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what makes the trochlear nerve susceptible to damage?
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it has the longest intracranial course of any cranial nerve
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what is the other name for CN VI? what does it innervate?
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the abducens nerve innervates the lateral rectus muscle.
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what orbital opening does CN VI pass through?
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superior orbital fissure
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where does CN VI originate?
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pons
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does CN VI have a ganglion?
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NO
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what are the four causes of isolated CN VI palsy?
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hypertension, diabetes, raised intracranial pressure, acoustic neuroma
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what is the ophthalmic artery a branch of?
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internal carotid
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what vein can allow facial infections to pass into the cavernous sinuses?
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ophthalmic vein
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of the things that pass through the superior orbital fissure, which travel within the common tendonous ring?
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III, VI, nasociliary of V1
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mnemonic for things that travel through superior orbital fissure but outside the common tendonous ring
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LOFT
Lacrimal nerve of V1 Ophthalmic vein Frontal nerve of V1 Trochlear Nerve |
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what are the 3 main layers of the eyeball?
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outer fibrous layer, middle vascular layer (uveal tract), retina.
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what are the 2 smaller layers of the outer fibrous layer of the eye?
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sclera, cornea
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what 3 things are found in the middle vascular layer of the eye?
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choroid, ciliary body, iris.
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what are the three functions of the ciliary body?
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controls shape of lens, suspends the lens, forms aqueous humor
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which layer of the middle vascular layer is vascularized?
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the choroid
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what are the two layers of the retina?
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pigmented layer and neural layer
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what are the borders of the anterior chamber of the inner eye?
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between cornea and iris
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what are the borders of the posterior chamber of the inner eye?
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between iris and lens
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what is the vitreous chamber?
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large space behind the lens filled with vitreous humor
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what is the optic disc?
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where the optic nerves leave the retina
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how to identify location of optic disc?
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branches of retinal artery converge here
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what is the macula lutea?
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thinnest area of retina
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where is the area of highest visual sensitivity on the retina?
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macula lutea
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what does the ciliary muscle do to the lens?
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constricts the ciliary body, which relaxes tension on the lens. this makes the lens more rounded and better for near vision
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what does the sphincter pupillae do?
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constricts pupil
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what is the dilator pupillae and what innervates it?
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dilates pupil and is innervated by sympathetic fibers
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what causes refractive errors?
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variations in eye size or corneal shape
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