Lecture 12: Eye and Eye Movements Flashcards
What structures exit the Optic Canal?
CN II
Opthalmic Artery
What structures pass through the Inferior Orbital Fissure?
Maxillary Nerve –> Infraorbital Nerve
Zygomatic Nerve (CN V2)
Infraorbital Artery
In comparision with the orbit, where are these sinuses located?
Frontal
Ethmoid
Maxillary
Sphenoid
- Frontal: superior and medial
- Ethmoid: medial
- Maxillary: inferior
- Sphenoid: posterior
What can cause optic neuritis?
Chronic infections in the ethmoid sinus that erodes into the orbit
What bone of the orbit is normally involved in an orbital blowout fracture?
Maxillary Bone
-Inferior to orbit
What are some consequences of an orbital blowout fracture?
- Diplopia (eyes not aligned)
- Globe ptosis (eyeball falling through orbit)
- Eye prolapses into maxillary sinus (if inferior bone breaks)
- Eye prolapses into ethmoid sinus (if medial wall breaks)
- Exophthalmos (protrusion of eyeball)
What is the movement of the eyeball around the vertical, horizontal, and AP axis?
Vertical Axis
- Abduction
- Adduction
Horizontal Axis
- Elevation
- Depression
AP Axis
- Intorsion (medial rotation)
- Extorsion (Lateral rotation)
What extra-ocular muscles abduct the eyeball?
Superior Oblique Muscle
Inferior Oblique Muscle
Lateral Rectus Muscle
What extra-ocular muscles adduct the eyeball?
Superior Rectus Muscle
Inferior Rectus Muscle
Medial Rectus Muscle
What extra-ocular muscles are involved in bilateral eyeball depression?
Superior Oblique Muscle
Inferior Rectus Muscle
What extra-ocular muscles are involved in bilateral eyeball elevation?
Superior Rectus Muscle
Inferior Oblique Muscle
How do you test exta-ocular eye muscles?
How do you test Superior Rectus, Inferior Rectus, Superior Oblique, and Inferior Oblique Muscles?
Trap an individual muscle and test its functional pair.
Basically do the opposite of its normal function
- Superior Rectus: Trap Inferior Oblique
- Inferior Rectus: Trap Superior Oblique
- Superior Oblique: Trap Inferior Rectus
- Inferior Oblique: Trap Superior Rectus
What structures go through the Cavernous Sinus?
- Oculomotor Nerve
- Trochlear Nerve
- Trigeminal Nerve
- Ophthalmic Nerve
- Maxillary Nerve
- Abducens Nerve
- Internal Carotid ARtery
What are branches of the Ophthalmic Nerve?
- Tentorial Nerve
- Lacrimal Nerve
- General sensation to lacrimal gland
- Parasympathetic innervation via Greater Petrosal Nerve (from CN VII)
- Frontal Nerve
- Supratrochlear Nerve (medial)
- Supraorbital Nerve (lateral)
- Nasociliary Nerve
What are branches of the Nasociliary Nerve?
- Anterior and Posterior Ethmoidal Nerve
- Nasal Cavity
- Long Ciliary Nerve (goes to cornea)
- Sensory
- Sympathetic
- Short Ciliary Nerve (comes off ciliary ganglion)
- Parasympathetic to iris and ciliary body
- Sympathetic
- Infratrochlear Nerve
What does the superior and inferior branches of the Oculomotor Nerve innervate?
Superior
- Levator Palpebrae Superioris Muscle
- Superior Rectus Muscle
Inferior
- Inferior Rectus Muscle
- Inferior Oblique Muscle
- Medial Rectus Muscle
What nerves pass through the superior orbital fissure?
- CN II: Optic Nerve
- CN III: Oculomotor Nerve
- CN IV: Trochlear Nerve
- CN V1: Ophthalmic Nerve
- CN VI: Abducens Nerve
What nerves pass through the common tendinous ring of the orbit?
- CN II: Optic Nerve
- CN III: Superior/Inferior divisions of Oculomotor Nerve
- CN V1: Nasociliary Nerve
- CN VI: Abducens Nerve
Common Tendinous Ring is made up of Rectus muscles
How does sympathetic innveration work with the eye muscles?
What are its actions?
Postganglioninc Sympathetic fibers arise from Superior Cervical Ganglion
- Will travel with Internal or External Carotid Plexus
Actions
- Deep Petrosal Nerve: constrict blood vessels
- Innervates Levator Papebrae Suprerioris to open eye
- Oculomotor Nerve
- Innervates Tarsal Muscles to keep eye opens
- Innverates Dilator Pupilae to dilate eye
-
Carries sensory info to choroid, iris, and cornea
- Ophthalmic Nerve
Travels through ciliary ganglion but does not synapse there!
How does parasympathetic innveration work with the eye muscles?
What are its actions?
Preganglioninc Parasympathetic run with Oculomotor nerve and will synapse in ciliary ganglion and then travel with Short Ciliary Nerves
Actions
- Innervate Sphincter pupillae
- Constrict eye
- Innervate ciliary muslce
- Can see farther
- Muscle relaxed and flattened
What are the 3 main symptoms of Horner Syndrome?
- Ptosis: droopy eyelid
- Anhidrosis: No sweat
- Miosis: constricted pupil
(PAM Horner)
A patient who is unable to look laterally with the left eye but is still able to perform all other ocular movements most likely has what disorder? What muscle is affected?
Abducens CN VI
Lateral Rectus M.
In a patient with CN IV palsy, what muscle is affected?
How will the patient compensate?
Superior Oblique Muscle
Patient will turn head down and away from the affected side
When would a patient complain the most of diplopia if they have trochlear palsy?
When they have downward gaze (reading or walking downstairs)