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Neuro Exam 1 > Orbit, Cavernous Sinus, And Eye > Flashcards

Orbit, Cavernous Sinus, And Eye Flashcards

1
Q

Bones of the orbit

The thinnest portion of the bones orbit is the _____ aspect.

A 
Sphenoid
Frontal 
Ethmoid
Maxillary
Lacrimal
Zygomatic
Palatine

Medial

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2
Q

What are three foramina in the orbit and what travels through these holes?

A

Supraorbital: supraorbital N

Superior orbital fissure: oculomotor N, trochlear N, ophthalmic division of trigeminal N, abducens N, ophthalmic V

Optic canal: optic N, ophthalmic A

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3
Q

The tendinous ring houses all the ____ of the eye.

The ____ assists in closing the eye. Innervated by _____ (temporal and zygomatic branches). What are the three parts of this muscle and what is their fx?

A

Muscles

Orbicularis oculi

CN VII

Palpebral: closing of lid
Lacrimal: increased lid contact to eye, dilates lacrimal sac

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4
Q

The ____ is skeletal muscle and acts as a direct antagonist to the orbicularis oculi and exposes (opens) the eyeball along with the superior tarsal muscle by lifting the eyelid. Innervated by _____.

A

Levator palpebrae superioris (LPS)

CN III

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5
Q

The _____ is smooth muscle and inserts onto the superior tarsus (dense CT). Innervated by postganglionic fibers originating from level of ____.

The _____ are modified sweat/sebaceous glands. Infection to these glands form a ____.

A

Superior tarsal m

T1

Ciliary glands (mebomian/moll’s glands)

Stye

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6
Q

Tears are formed by the ____ at the supero-lateral aspect of the orbit. Tears are drained by the ____ located on the medial aspect of the orbit and eventually drain into the ____.

A

Lacrimal gland

Lacrimal canaliculi

Inferior meatus

Lacrimal gland -> lacrimal canaliculi -> lacrimal sac -> nasolacrimal duct -> inferior concha

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7
Q

Sympathetic innervation of the lacrimal gland is the _____.

The parasympathetic innervation of the lacrimal gland starts in the ____ nucleus -> facial N(CN VII)/greater petrosal N -> Vidian N -> ______ -> zygomatic N (CN V2)-> _____.

A

Superior cervical ganglion (carotid plexus)

Superior salivatory nucleus

Sphenopalatine ganglion (pterygopalatine ganglion)

Lacrimal N (CN V1)

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8
Q

What are the three main branches of CN V1?

A

Nasociliary N

Frontal N -> supraorbital N and supratrochlear N

Lacrimal N

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9
Q

Fractures of the bony orbit due to high velocity trauma?

Caused by?

Clinical signs?

What causes the diplopia (double vision usually of upward gaze)?

A

Blow-out fracture

High-velocity trauma (AP direction)

Periorbital ecchymosis, edema, point tenderness, diplopia, decreased visual acuity, decreased pupillary reflex, displacement of structures into maxillary sinus

Due to entrapment of inferior rectus muscle (EOM)

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10
Q

Fractures of maxillary region of the skull called?

Caused by?

What are the three types?

A

Le forte fractures

High-velocity trauma

Type 1: above alveolar processes; avoids orbit

Type 2: pyramidal shape involving medial portion of orbit

Type 3: Craniofacial dysfunction; transverse fracture across both orbits and nasofrontal sutures; separation from base of skull; caused by severe lateral force trauma

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11
Q

What are clinical signs of Le forte fractures?

A

Lower lip swelling; ecchymosis; damaged teeth (type 1); periorbital edema; CSF rhinorrhea; nasal disfigurement (type 2); panda facies; complete mobility of facial skeleton; antimongoloid slant (type 3)

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12
Q

Paired dural venous sinuses are found between the ____ and ____ layers of the dura mater. They are parasagittal to the hypophysis and bounded by brain, sphenoid bone, and temporal bone.

Sphenoidal sinuses are inferior to the ____.

A

Endosteal and meningeal

Cavernous sinus

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13
Q

What six structures are contained in the cavernous sinus?

A

CN III, CN IV, CN V1, CN V2, internal carotid A, CN VI

OTOM CAT

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14
Q

Cavernous sinus is a ______ that drains blood from the ophthalmic veins eventually delivering blood to the ____ and the IJV.

A

Paired dural venous sinus

Petrosal sinuses

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15
Q

_____ is enlargement of sinus due to venous congestion secondary to hematological obstruction (thrombus)

Caused by?

Infection spreading to the facial V leads to _____.

Clinical signs?

A

Cavernous sinus thrombosis

Infection (mainly bacteria), thrombophilic disorders

Leads to obstruction in smaller compartments (petrosal sinus)

Unilateral periorbital edema and proptosis, HA, photophobia, impingement syndrome (CN VI)

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16
Q

What are the fibrous layers of the eye?

Vascular layers?

Inner layers?

A

Sclera: covered by bulbar conjunctiva, thin highly vascular membrane; pink eye is and inflammation of sclera
Cornea

Choroid: between sclera and retina
Ciliary body: attachment for lens that connects choroid to iris; controls thickness of lens; secretes aqueous humor (ciliary processes)

Retina

17
Q

___ is the point for retinal neuronal axons to form optic N.

_____ area for high resolution, color distinction vision.

___ is swelling to optic disc due to increases in CSF.

A

Optic disc

Macula lutes

Papilledema

18
Q

_____ is a blinking response arc directed by what two cranial nerves?

Describe the input verse the output?

A

Corneal reflex

CN V, CN VII

Input: nasociliary N/long ciliary N (CN V1)

Output: facial N -> orbicularis oculi (CN VII)

19
Q

_____ is a pigmented structure acting as a boundary between the anterior and posterior compartments of the eye.

Hole in iris leading to lens is ____.

A

Iris

Pupil

20
Q

Two muscles in the iris that controls the diameter of the pupil?

A

Sphincter pupillae m -> constricts (miosis; parasympathetic)

Dilator pupillae m -> dilates (midriasis; sympathetic)

21
Q

Pupillary constriction reflex

A

J

22
Q

Pupillary dilation reflex

A

J

23
Q

The ____ controls the lens to focus light. They are attached to _____ which attach to lens.

Parasympathetic stimulation causes the ciliary muscle to ____ and zonular fibers to ___.

A

Ciliary muscle

Zonular fibers

Constrict; relax

24
Q

A _____ reflex focuses on close structures/objects.

Outputs are sent out by occipital lobe to perform three fx simultaneously?

A

Cortically mediated

Convergence (pupils adduct)

Pupillary constriction

Lens thickening (nearsightedness)

25
Q

The ophthalmic A is the chief A of the orbit and branches off the internal carotid A

What are branches off the ophthalmic A and what do they supply?

A

Posterior ciliary A and central retina A: optic N

Central retina A: retina

Supraorbital A: upper and lateral portion of eyelid and scalp

Supratrochlear A: medial portion of eyelid and scalp

Anterior ethmoidal A: nasal cavity and external nose

26
Q

Six extrinsic muscles that attach to the sclera assist in movement of the eyeball?

Innervation?

Fx?

A

Medial rectus m: CN III
Lateral rectus m: CN VI
Inferior rectus m: CN III
Superior rectus m: CN III

Superior oblique m: CN IV
Inferior oblique m: CN III

(SO4, LR6, rest 3)

Rectus muscles move in direction of name
Oblique muscles move in opposite direction of name

27
Q

CN III lesion causes pupil to be _____.

CN VI lesion causes pupil to be _____.

CN VI lesion causes pupil to be ____.

A

Down and out pupil

Extorted pupil, verticals diplopia, compensatory head tilt and tucking of chin (torticollis)

Medially rotated pupil

28
Q

Drooping of upper eyelid is ____.

What muscles contribute to motion of upper eyelids?

Which is stronger and why?

Innervation to each muscle?

A

Ptosis

LPS, superior tarsal m

LPS (striated, skeletal m)

LPS: CN III
Superior tarsal m: SNS

29
Q

Complete ptosis is due to ____ palsy.

Caused by?

Pupil presentation?

Brainstem nuclei involved?

A

CN III palsy

Focal obstruction by tumors, vascular malformations, abscess

Down and out; pupillary dilation because loss of pupillary constriction reflex

Edinger Westphal Nucleus

30
Q

Oculomotor N innervates what?

A

SR, IR, IO, MR

Levator palpebrae superioris

Pupillary constriction reflex

31
Q

Partial ptosis is due to dysfunction of ____.

Tarsal muscle innervation is postganglionic nerves arising from ____.

What syndrome does this contribute to?

What causes this?

A

Superior tarsal m

Cervical sympathetic ganglion on internal carotid A

Horner’s syndrome: partial ptosis, anhydrosis, mioisis

Obstruction/destruction of sympathetic ganglion arc (possibly from pancoast tumor/lung cancer)

Neuro Exam 1 (15 decks)

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