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The EYE. Name the 7 bones associated with the orbital. frontal , ethmoid , maxilla , lacrimal , zygomatic , palatine and sphenoid. The medial wall of the orbital is made off what bone(s). The medial walls are parallel and separated by the ethmoid and sphenoid sinuses.
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Name the 7 bones associated with the orbital. • frontal, • ethmoid, • maxilla, • lacrimal, • zygomatic, • palatine and • sphenoid
The medial wall of the orbital is made off what bone(s) • The medial walls are parallel and separated by the • ethmoidand • sphenoid sinuses.
The roof of the orbital is made up of what bones? • the orbital plate of the frontal bone. • It contains the lacrimalfossa that contains the lacrimal gland laterally
The lateral wall consists of which bones? • the zygomatic bone and greater wing of the sphenoid • This wall is divergent ( it angles inward)
The floor is largely composed of which bones and containes what other structure(s)? • the orbital surface of the maxilla • It contains the infraorbital groove in which the infrorbital nerve (a branch of the maxillary division of the trigeminal nerve, CN V) lies. • Seperates orbit from what sinus? • The maxillary
The medial wall consists of which bones? • orbital lamina of the ethmoidbone which seperates what from what? • ethmoid air cells and sphenoid sinus from the orbit. • lacrimal bone, which contains what? • The lacrimal bone contains the lacrimalfossa that holds the lacrimal sac • the frontal process of the maxilla.
The apex is formed by which bone? • sphenoid bone and contains several openings that include? • 1) the optic canal contains the optic nerve and ophthalmic artery; • 2) the superior orbital fissure contains cranial nerves III, IV, V1, and VI, and superior ophthalmic vein. The inferior orbital fissure contains branches of the maxillary nerve and vessels.
The eyelids contain 5 layers name them NOW! • 1) skin; • 2) subcutaneous tissue; • 3) muscles; • 4) tarsal plate and • 5) conjunctiva.
The eyelids are composed of 3 muscles can you please name them at your leisure? • orbicularisoculi, the sphincter muscle of the • Innervated by what nerve? • Facial nerve (CN VII); • levatorpalpebraesuperioris, • Innervated by what nerve? • Oculomotornerve (CN III), • superior tarsal muscle (Muller’s muscle) • innervated by what? • sympathetic branches from the superior cervical ganglion.
What does the tarsal plate do and what does it contain? • The tarsal plate provides support to the eyelid. • It contains tarsal glands (sebaceous glands).
A meibomian cyst (chalazion) or, when infected, an internal hordeolum is an infection of what? • Inflammation of the tarsal glands
The difference between a chalazion and a hordeolum is that the chalazion is what? • a granuloma formed from extravasated lipid whereas, a hordeolum is an acute suppurative infection usually caused by what pathogen? • Staphylococcus aureus.
The orbital septum is composed of what and its importance? • superior and inferior palpebral fascia. • It connects the tarsal plates with the periosteum of the orbit. • It forms a circumferential curtain that serves as a barrier to infection by separating the superficial subcutaneous tissues from the deeper structures of the orbit.
The conjunctiva consists of what two parts? • palpebraland bulbar • Which is on the sclera? • Bulbar • Which one covers the cornea? • None of them do. • Under the lid? • duh palpebral
What are found at the base of an eyelash? • Ciliary glands • These include which specific glands? • Glands of Zeiss • and Moll)
What gland is associated with a hordeolum or chalazion? • The glands of Zeis are sebaceous glands which may become infected and produce an external hordeolum (sty), or may develop a chalazion (non-infectious).
What tyoe of gland is the gland of Zeis? • a sebacous gland?
The glands of Moll are what type of gland? • Cilliary glands that are apocrineand eccrine sweat glands • What type of infections are ass.ed with them? • external hordeolum
The lacrimal apparatus consists of what structures? • lacrimalgland, • lacrimalpapillae, • lacrimalpuncta, • lacrimalsac, and • nasolacrimalduct
Trace a tear from its source to the nose. • lacrimalgland is • lacrimalducts • the conjunctivalfornix • lacrimalpuncta located on the lacrimal papillae which are found on the medial corner of the eyelid • lacrimalsac • where they drain via the nasolacrimal duct • the inferior meatus of the nasal cavity
Name the6 extraocular muscles that control the movement of the eye. • superior, • inferior, • medial and • lateral rectus muscles; • and superior and • inferior oblique muscles.
Which EOM does not originate at the apex of the orbit? • inferior oblique originate • Then where does it originate? • The medial wall.
What nerves innervate each eye muscle? • LR6 • Lateral rectus • SO4 • Superior oblique • AO 3 • All others
What is the anatomical movement of Lateral Rectus? • lateral rectus : abduct the lateral movement of eye • Clincal exam • Abduct out
What is the anatomical movement of Superior Oblique? • Superior oblique muscle: depress and Abduct • Down and Out • Clincal Exam • depress and adduct ******** • Down and in
What are the anatomical movements of the Medial rectus • Medial rectus Adduct eye • Clinical Exam • Adduct
What is the anatomical movement of superior rectus ? • superior rectus elevate and adduct • Clincal Exam • elevate and abduct Up and out *******
What is the anatomical movement of the inferior rectus? • Inferior rectus depress and adduct • Clinical Exam • Depress and abduct **********
Anatomical movement of inferior oblique? • Inferior oblique elevate and abduct • Clinical Exam • Elvates and adducts
Why should the anatomic movement and motion for clinical testing be different for 4 of the 6 extraocular muscles? • Since these four muscles have multiple movements it is necessary to isolate one movement for testing. • By turning the eye inward (adduction) you prevent the superior and inferior rectus muscles from elevating or depressing the eye. • Since the superior and inferior oblique also depress and elevate the eye, they are actively tested when the eye is in the adducted position. • Ask the patient to elevate the eye to test the inferior oblique, • Depress the eye to test the superior oblique. • Conversely, when the eye is turned outward (abducted), the superior and inferior oblique muscles cannot depress or elevate the eye. Thus, the superior and inferior rectus muscles are isolated in their movements of elevating and depressing the eye respectively. • To help with remembering cranial nerve innervations use the mnemonic; LR6SO4 AO3 (lateral rectus CN VI, superior oblique CN IV, all others CN III).
The axis of the bony orbit is 23 degrees lateral to the optic axis of the eye. The rectus muscles are arranged parallel to the axis of the orbit. When the superior and inferior rectus muscles contract, they pull the globe of the eye medially as well as superiorly and inferiorly. By abducting the globe of the eye 23 degrees, the superior and inferior rectus muscles become aligned parallel to the optic axis. In this position, they only elevated and depress the eye. In a similar fashion, by adducting the eye 50 degrees, the superior and inferior oblique muscles become aligned parallel to the optic axis. In this position, the superior oblique depresses the eye, and the inferior oblique elevates
A lession in CN II will cause the eye to do what? • CN III lesions result in the eye being “down and out” at rest.
CN IV lesions result in the eye doing what? • Deviated upward (unilateral hypertropia), and the person’s head is held in a contralateral tilt.
What nerve has autonomic and parasympathetic innervations of the eye? • The oculomotor nerve (CN III) carries Autonomic innervation of the eye. and • parasympathetic innervationto what structures of the eye? • the iris and ciliary muscle.
What muscles changes the size of the pupil? • Within the iris CN III innervates the sphincter pupillae muscle resulting in pupil constriction durring which conditions miosis? • during conditions of intense light or relaxation
What muscles acts on the lens? • The ciliarymuscle causes ciliary muscle contraction which relaxes the zonular fibers (suspensory ligaments) attached to the lens, thus permitting the lens to thicken during accommodation (near vision).
What nerve innervates a muscle that cause mydriasis? • The sympathetic nerves from the superior cervical ganglion • What muscle does this innervate? • innervate the dilator pupillae muscle of the iris resulting in pupil dilation (mydriasis) in low light or in the fight or flight response.
Horner syndrome is caused when? • occurs as a result of disruption of the sympathetic nerve pathway to the eye and face
What are the symptoms of Horners syndrome? • unilateral ptosis, caused by? • The ptosis results from weakness of Muller’s muscle in the superior eyelid • miosis, and caused by? • impaired papillary dilation • Anhidrosis caused by ? • lack of sympathetic innervation of sweat glands in the face
Horner syndrome include ? • lateral brainstem infarct, • spinal cord trauma, • apical lung tumor (Pancoast syndrome), trauma or tumor affecting the sympathetic chain, • cavernous sinus thrombosis or infection, • and infections of the orbit of the eye.
The central artery of the retina comes from where? • the first branch of the ophthalmic artery (which is a branch of the internal carotid artery). • Where / what does it innervate? • It pierces the optic nerve and is accompanied by the central vein of the retina.
Where does the superior opthalamic vein enter the orbit? • via the supraorbital notch. Within the orbit it is joined by the inferior ophthalmic vein. • Where does the inf. Opthalmic vein exit the orbit? • via the superior orbital fissure • Where does it go from there? • drains into the cavernous sinus.
This valueless vein serves as a route for the dissemination of infection and emboli from the face into the cranial cavity and brain • The superior ophthalmic
The cavernous sinus lies where? • on either side of the sphenoid bone within the middle cranial fossa
The sphenoid bones contain what structures? • Cranial nerves • III, • IV, • V1, • and VI; • and internal carotid artery. • It is adjacent to the optic nerve and chiasm, and pituitary gland.
The optics nerve enter thru which bone? • The optic nerve enters the optic canal of the sphenoid bone
The optic nerve is covered by what? • dura, • arachnoidand • piamater that • covers the nerve all the way to the back of the eye • The summation of all theses are called what? • the orbital sheath • The subarachnoid space, thus extends all of the way to the back of the eye.