Eye and Eye Movements Flashcards
What bones form the orbit?
Frontal Ethmoid Sphneoid (greater wing) Zygomatic Lacrimal Maxillary
Draw the anatomical relationship of the paranasal sinuses - frontal, ethmoid and maxillary sinuses
REfer to drawings
What happens if you get an infection in the ethmoid sinuses?
Infection can erode to the orbits and cause optic neuritis
Orbital Blow out fractures:
Fracture of the orbital walls caused by indirect trauma
Usually occurs medially and inferiorly involving the maxillary bone
Contents of the orbit may prolapse and entrapped in the maxillary sinus
Clinical: diplopia, globe ptosis, exophthalmos (protrusion of eyeball)
Describe the position of the orbital globe
Medial walls are parallel but lateral walls are right angles to each other , causing the axes of the orbit to diverge at 45 degrees while the axes of gaze are parallel
Draw out the different movements of the pupil and their axis
Refer to drawings
Draw the schematic for remembring EOM actions:
Refer to drawings
How would you clinically test the EOMs?
H test, Superior/inferior rectus and obliques are tested through actions opposite their actions
So to test Inferior/superior Oblique: Adduct the eye (since these are abductors)
To test the superior/inferior rectus: Abduct the eye
How do you discriminate between muscle and nerve dysfunction?
Trap one muscle and test the muscle doing opposite the movement. Trapping means the visual gaze axis is perpendicular to muscle fiber direction
Long ciliary N. and short ciliary N. innervation:
Sensation to cornea and sympathetic to dilator pupilae
Short ciliary carries parasympathetic fibers to dilator pupillae
Long ciliary carries … fibers
Short Ciliary carries …. Fibers
Sympathetic to dilator pupilae
parasympathetic to sphincter pupilae
Which nerves go through the superior orbital fissure?
What is the tendinous ring? Which nerves go through it?
Lacrimal, frontal and trochlear. Do NOT pass through the tendinous ring
Formed by the rectus muscles. Oculomotor, Abducens, Nasociliary (also passes through the superior orbital fissure)
*OAN passes through both
Optic nerve passes through ….
Tendinous ring and optic canal
Draw the sympathetic pathway of eye movement:
REfer to drawings
What do the sympathetic fibers of the external carotid plexus innervate?
Salivary glands, sweat glands, blood vessels (vasoconstriction)
What comes off the internal carotid plexus:
Deep petrosal N. (sympathetic). Joins greater petrosal N. (parasympathetic) to form the N. of the pterygoid canal. Sympathetic fibers join the parasympathetic pterygopalatine ganglion to the blood vessels
How is the eye sympathetically innervated?
From the Internal carotid plexus, sympathetic fibers jump on to nerves that will get them where they wanna go.
Via ciliary ganglion (parasympathetic) then short ciliary N. > dilator pupilae (do sympathetic stuff!)
Via the nasociliary N. > dilator pupilae.
Via the Superior root of CN III then > superior tarsal muscle (keep eyes open!)
Horner’s syndrome:
Cause
Clinical
Damage to the sympathetic innervation of the head and neck. No sympathetics = parasympathetics take over.
Constricted pupil, ptosis (eyes staying shut), anhydrosis (no sweat), vasodilation leading to flushing of skin,
Draw the parasympathetic pathway of eye movement:
Refer to drawings
Describe parasympathetic innervation to the eye:
From parasympathetic root of the Ciliary ganglion > Synapse at ciliary ganglion > post synaptic parasympathetic travels to the sphincter pupilae and ciliary muscle to constrict the pupil
Trochlear palsy:
Superior oblique paralysis. Eye is laterally rotated.
Patient presents with eye tilted away from affected side. Diplopia worse on downward gaze.