Orbit

Question 1

Long axis of the orbit is directed in what 2 directions

Answer 1

Posterior and medially

Question 2

Anterior opening of the orbit is surrounded by the orbital margin - what is the orbital margin formed by

Answer 2

Frontal and zygomatic bones and maxilla

Question 3

Walls of the orbit:

1. Superior wall separates orbit from?
2. Inferior wall separates orbit from?
3. Lateral separates orbit from?
4. Medial separates orbit from?

Answer 3

1. Separates orbit from anterior cranial fossa
2. Separates orbit from maxillary sinus
3. From middle cranial fossa and temporal fossa
4. From ethmoidal air cells

Question 4

Walls of the orbit:

1. Superior wall is formed by?
2. Inferior wall is formed by?
3. Lateral wall is formed by?
4. Medial wall is formed by?

Answer 4

1. Orbital plate of frontal bone and lesser wing of sphenoid
2. Orbital surfaces of body of maxilla and zygomatic bone/orbital process of palatine
3. Orbital surfaces of zygomatic bone and greater wing of sphenoid
4. Frontal process of maxilla, lacrimal bone, orbital plate of ethmoid, and a small part of body of sphenoid

Question 5

Optic canal:

1. Opening between what 2 things?
2. What nerve and artery does it transmit?

Answer 5

1. Opening between 2 roots of lesser wing of sphenoid

2. Optic nerve and ophthalmic artery

Question 6

Superior orbital fissure:

1. Opening between what 2 things?
2. Transmits what vein?
3. Transmits what 3 nerves
4. Transmits branches of what nerve? What 3 branches?

Answer 6

1. Greater and lesser wing of sphenoid 2. Superior ophthalmic vein
2. CN III, CN IV, and CN VI
3. Branches of ophthalmic nerve (V1) - frontal, lacrimal and nasociliary

Question 7

Inferior orbital fissure:

1. Opening between what 2 things?
2. Transmits what nerves/vessels (2)
3. Transmits vein that communicates between what 2 veins?

Answer 7

1. Greater wing of sphenoid and maxilla
2. Infraorbital nerve/vessels and zygomatic nerve/veins
3. Communicating inferior ophthalmic vein with pterygoid venous plexus

Question 8

Supraorbital notch (or foramen):

1. Located at junction of ?
2. Transmits what nerve/vessels

Answer 8

1. Medial and middle thirds of superior orbital margin

2. Supraorbital nerve/vessels

Question 9

Infraorbital groove:

1. Location?
2. Continuous anteriorly with __, which opens onto face via ?
3. These 3 spaces transmit what nerve/vessels

Answer 9

1. Floor of orbit
2. Infraorbital canal which opens onto face via infraorbital foramen
3. Infraorbital nerve/vessels

Question 10

Fossa for lacrimal sac:

1. Depression located where?
2. Continuous inferiorly with? (This houses what?)
3. Communicates orbit with?

Answer 10

1. Anterior part of medial wall of orbit
2. Nasolacrimal canal which houses nasolacrimal duct
3. Inferior nasal meatus

Question 11

Anterior and posterior ethmoidal foramina:

1. Located along?
2. Transmits what nerve/vessels?

Answer 11

1. Frontoethmoidial suture

2. Anterior and posterior ethmoidal nerves and vessels

Question 12

Orbital surface of zygomatic bone:

1. __ part of lateral wall of orbit
2. Has small openings for canals that transmit what 2 nerves/vessels

Answer 12

1. Anterior

2. Zygomaticofacial and zygomaticotemporal nerves/vessels

Question 13

There are 7 extraocular muscles; 6 move the eyeball, 1 does?

Answer 13

Elevates upper eyelid

Question 14

Rectus muscles:

1. How many are there?
2. Origin?
3. Insertion?
4. Innervation?

Answer 14

1. 4 (superior, inferior, lateral and medial)
2. Common tendinous ring which surrounds optic canal and inferomedial part of superior orbital fissure
3. Into sclera, posterior to corneoscleral junction
4. Lateral rectus= abducens nerve; other 3= oculomotor nerve

Question 15

Levator palpebrae superioris:

1. Origin?
2. Course?
3. Insertion?
4. Innervation?
5. Action?

Answer 15

1. Sphenoid, above optic canal
2. Passes forward under orbit roof and ends anteriorly in a broad tendon
3. Into superior tarsus and skin of upper eyelid
4. Oculomotor
5. Elevate upper eyelid

Question 16

Superior tarsal muscle (of Muller)

1. Extends from where to where?
2. Innervation
3. Action

Answer 16

1. Extends from inferior surface of levator palpebrae superioris to superior tarsus
2. Sympathetic fibers from superior cervical ganglion
3. Elevates upper eyelid

Question 17

Superior oblique muscle:

1. Location
2. Origin?
3. Course?
4. Tendon changes direction and goes where?
5. Insertion?
6. Innervation

Answer 17

1. In superomedial part of orbit
2. Sphenoid (superior and medial to optic canal)
3. Passes anteriorly and becomes continuous with a tendon, tendon passes thru trochlea attached to anteromedial part of orbital roof
4. Passes posteriorly and laterally, under superior rectus muscle
5. Into sclera of superior posterolateral aspect of eyeball
6. Trochlear nerve

Question 18

Inferior oblique muscle:

1. Location
2. Origin
3. Course
4. Insertion
5. Innervation

Answer 18

1. Inferior to eyeball, close to orbital margin
2. Orbital surface of maxilla, just lateral to fossa for lacrimal sac
3. Passes posteriorly and laterally, below inferior rectus muscle
4. Inserts into sclera of inferior posterolateral aspect of eyeball
5. Oculomotor nerve

Question 19

What position does the eyeball have to be in to test the following muscles clinically

1. Lateral rectus
2. Medial rectus
3. Superior rectus
4. Inferior rectus
5. Inferior oblique
6. Superior oblique

Answer 19

1. Eye abduction
2. Eye adduction
3. Elevation of abducted eye
4. Depression of abducted eye
5. Elevation of adducted eye
6. Depression of adducted eye

Question 20

Which muscle do you lose function of in Horners syndrome?

Symptoms?

Answer 20

Superior tarsal muscle

Ptosis, anhydrosis, and miosis

Question 21

Why does the eye have to be abducted in order to test the inferior rectus and superior rectus

Answer 21

Once the eye is abducted, the inferior rectus is a pure depressor of the eye and the superior rectus is a pure elevator of the eye

Question 22

Optic nerve:

1. Formed by?
2. Begins at?
3. Leaves orbit and enters ? Via?
4. What is the optic nerve surrounded by? These fuse where?
5. What causes swelling of the optic disc (papilledema)

Answer 22

1. Axons of ganglion cells of retina
2. Optic disc
3. Middle cranial fossa via optic canal
4. Pia, arachnoid, and dura mater which fuse with sclera
5. Increased pressure of CSF within cranial cavity

Question 23

Optic nerve is myelinated by __ cells

So optic nerve is commonly affected by what disease?

Answer 23

Oligodendrocytes

Mulitple sclerosis

Question 24

Oculomotor nerve:

1. Contains what 2 types of motor fibers
2. Emerges from?
3. Runs forward in?
4. Divides into superior and inferior branches that enter orbit via
5. Inferior branch supplies which muscles(3)?
6. Also gives a short branch to __

Answer 24

1. Somatic motor and visceral motor (preganglionic parasympathetic)
2. Midbrain
3. Lateral wall of cavernous sinus
4. Superior orbital fissure
5. Medial rectus, inferior rectus, and inferior oblique
6. Ciliary ganglion (contains preganglionic parasympathetic fibers)

Question 25

Ciliary ganglion: 1. What type of fibers? 2. Located between? 3. Receives preganglionic fibers from which nerve? 4. Axons of the postganglionic (after synpase) fibers go where? To do what?

Answer 25

1. Parasympathetic* 2. Between optic nerve and lateral rectus muscle (so posterior part of orbit) 3. Inferior branch of oculomotor nerve 4. Pierce sclera to enter the eye and innervate ciliary muscle and sphincter pupillae muscle

Question 26

Ciliary ganglion 1. Receives general sensory fibers from which nerve 2. Receives post-ganglionic sympathetic fibers from where 3. Do they synapse at the ciliary ganglion?

Answer 26

1. Ophthalmic nerve 2. Superior cervical ganglion 3. No, these fibers pass thru and get incorporated into short ciliary nerves

Question 27

Trochlear nerve: 1. Contains what type of fibers 2. Where does it attach 3. Runs where? 4. Enters orbit thru? 5. Innervates which muscle?

Answer 27

1. Somatic motor fibers 2. Posterior aspect of brainstem (only CN that attaches here) 3. Forward in lateral wall of cavernous sinus 4. Superior orbital fissure 5. Superior oblique muscle

Question 28

Abducens nerve: 1. Contains what type of fibers 2. Attaches to? 3. Runs ? 4. Enters orbit via 5. Innervates which muscle

Answer 28

1. Somatic motor fibers 2. Medullopontine sulcus (close to midline) 3. Forward inside cavernous sinus 4. Superior orbital fissure 5. Lateral rectus muscle

Question 29

Contents of the cavernous sinus?

Answer 29

ICA and CN III, IV, V1, V2, IV

Question 30

What innervates the ciliary muscle and sphincter pupillae muscle?

Answer 30

Post-ganglionic parasympathetic fibers that arise from the ciliary ganglion

Question 31

Lesion of oculomotor nerve: 1. Eye will be in what direction 2. 4 symptoms

Answer 31

1. Turned down and out | 2. Double vision, dilated pupil, palpebral ptosis, loss of accommodation/light reflex in affected eye

Question 32

Lesion of trochlear nerve 1. Eye will be in what direction 2. *Will result in inability of eye to do what 3. Symptom? What makes this symptom improve

Answer 32

1. Extorsion (outward rotation of the eye) and elevation of affected eye 2. Inability to depress adducted eye on side of lesion 3. Double vision which worsens when looking down (can’t go down stairs); improves when tilting your head away from affected eye

Question 33

Lesion of abducens nerve 1. Inability to do what motion 2. Location of affected eye 3. Symptom

Answer 33

1. Abduct affected eye 2. Medially deviated 3. Double vision

Question 34

Ophthalmic nerve (V1) 1. Contains what kind of fibers 2. Origin 3. 4 branches? 4. Runs ?

Answer 34

1. General sensory fibers 2. Trigeminal ganglion 3. Tentorial (meningeal), frontal, lacrimal, and nasociliary nerves 4. In lateral wall of cavernous sinus

Question 35

Tentorial branch of V1 supplies?

Answer 35

Dura mater of tentorium cerebelli

Question 36

Lacrimal nerve branch of V1: 1. Runs? 2. Receives communicating branch from? 3. Supplies? 4. Its terminal branches supply?

Answer 36

1. Along superior border of lateral rectus muscle 2. Zygomaticotemporal nerve 3. Lacrimal gland 4. Lateral part of upper eyelid

Question 37

Zygomaticotemporal nerves contains what kind of fibers

Answer 37

Post-ganglionic parasympathetic fibers for lacrimal gland

Question 38

Frontal nerve branch of V1 1. Location 2. Divides into what 2 nerves

Answer 38

1. Immediately above levator palpebrae superioris | 2. Supraorbital and supratrochlear nerves

Question 39

Supraorbital nerve: 1. Passes through? 2. Innervates what 4 things?

Answer 39

1. Supraorbital notch | 2. Mucosa of frontal sinus, central part of upper eyelid, forehead, and anterior scalp

Question 40

Supratrochlear nerve: 1. Passes above? 2. Innervates what 2 things?

Answer 40

1. Trochlea of superior oblique muscle | 2. Medial part of upper eyelid and medial forehead

Question 41

Nasociliary nerve of V1 1. Course? 2. Divides into what 2 terminal branches?

Answer 41

1. Passes above optic nerve and then runs anteriorly along medial rectus 2. Anterior ethmoidal and infratrochlear nerves

Question 42

Branches of nasociliary nerve: 1. Communicating branch has? 2. Long ciliary nerves innervate? 3. Posterior ethmoidal nerve innervates? 4. Infratrochlear nerve ? 5. Anterior ethmoidal nerve

Answer 42

1. Ciliary ganglion; general sensory fibers 2. General sensory innervation to eyeball 3. Mucosa of ethmoidal air cells and sphenoidal sinus 4. Lacrimal sac, medial part of upper eyelid, and adjacent part of nose 5. Ethmoidal air cells

Question 43

Long ciliary nerves supply general sensory to eyeball and also contain what kind of fibers for what muscle?

Answer 43

Post-ganglionic sympathetic fibers for dilator pupillae muscle

Question 44

Anterior ethmoidal nerve: 1. After supplying ethmoidal air cells, nerve enters where? 2. Divides into what 2 branches? 3. What do these branches supply

Answer 44

1. Nasal cavity (near side of crista galli) 2. Internal and external nasal branches 3. Internal= mucosa of anterior parts of lateral wall and septum; External= skin of lower part of nose