Orbit and Eye

Question 1

Bones of Orbit

Answer 1

1. Frontal
2. Zygyomatic
3. Maxillary
4. Lacrimal
5. Ethmoid
6. Palatine
7. Sphenoid

Question 2

Structures passing through Optic Canal

Answer 2

1. CN II
2. Opthalmic artery

Question 3

Structures through Superior Orbital Fissure

Answer 3

1. CN III
2. CN IV
3. CN V1
4. CN VI

Question 4

Structures through Inferior orbita fissure & infraorbital groove

Answer 4

1. Infraorbital nerve
2. Infraorbital vessels

Question 5

Strucutres through Anterior & Posterior Ethmoidal Foramina

Answer 5

• Ant/Post ethmoidal nerves
• Ant./Post Ethmoidal vessels

Question 6

Components of Eyelid

Answer 6

• Skin
• Subcutaneous tissue
• Levator Palpebrae Superioris
• Orbital Septum
• Tarsus
  
  • contain Meibomian (tarsal) glands
  • superior/inferior tarsus muscle
• Conjunctiva
  
  • Thin membrane covering inner eyelid

Question 7

Branches of V1

Answer 7

• Frontal
• Supratrochlear
• Supraorbital
• Lacrimal

Question 8

Terminal ganglion of V1 and location

Answer 8

Gasserian/Semi-lunar ganglion in Meckel’s Cave

Question 9

Pathway of tears from lacrimal gland

Answer 9

Lacrimal glands–>surface of cornea–>lacrimal canaliculi –> lacrimal sac–> nasolacrimal duct

Question 10

Innervation of Lacrimal Gland

Answer 10

• _General Sensory _
  
  • Lacrimal Nerve (Branch of V1)
• Parasympathetic
  
  • Greater Petrosal Nerve (branch of VII) via **V1 **
• _Sympathetic _
  
  • **Deep Petrosal Nerve **(branch of Carotid Plexus) via V1

Question 11

Path of parasympathetic innervation of Lacrimal Gland

Answer 11

VII –> Greater Petrosal Nerve –> Pterygoid canal –> Pterygopalatine ganglion –> Zygomaticotemporal nerve of V2 –> Lacrimal nerve of V1 —> Lacrimal Gland

Question 12

Path of Sympathetic Innervation of Lacrimal Gland

Answer 12

Carotid Plexus –> Deep Petrosal nerve –> pterygoid canal –> pterygoid ganglion –> Zygomaticotemporal nerve of V2 –> Lacrimal Nerve of V1 –> Lacrimal Nerve of V1

Question 13

Branches of V1 Nerve

Answer 13

• Frontal
• Supratrochlear
• Lacrimal
• Supraorbital
• Nasociliary Nerve

Question 14

Branches of Nasociliary Nerve

Answer 14

• Long ciliary
• Short Ciliary
• Anterior ethmoidal
• Posterior ethmoidal
• Infra-trochlear

Question 15

Optic Nerve (II)

Answer 15

• Origin: Lateral Geniculate Body
• Course: Left and Right Optic Tracts cross and travel through optic canal
• Components: Special Sensory
• Ganglion:“Ganglion cells” of Retina (cell bodies here)`a
• Function: Vision

Question 16

Incyclotorsion and what mediated by

Answer 16

Depression, abduction, and medial rotation

• Mediated by **Superior Oblique **

Question 17

Excyclotorsion and mediated by what muscle

Answer 17

Elevation, abduction, lateral rotation

• Mediated by Inferior Oblique

Question 18

Superior Rectus

Answer 18

• Elevation and Adduction
• Innervated by III (Superior division)

Question 19

Inferior Rectus

Answer 19

• Depression and Adduction
• Innervated by III (Inferior division)

Question 20

Superior Oblique

Answer 20

• Depression and Abduction
• Incyclotorsion
• Innervated by IV (Trochlear)
• Goes through Trochlea (pulley system)

Question 21

Inferior Oblique

Answer 21

• Elevates and Abducts
• Innervated by III (Inferior division)
• Excyclotorsion

Question 22

Lateral Rectus

Answer 22

• Abducts eye
• Innervated by VI (Abducens)

Question 23

Medial Rectus

Answer 23

• Adducts eye
• Innervated by III (Inferior division)

Question 24

Levator Palpebrae Superioris

Answer 24

• Elevates eyelid
• Innervated by III (Superior Division)

Question 25

Occulomotor Nerve (III)

Answer 25

**Origin:** Oculomotor nucleus (Somatic Motor) & E-W nucleus (para visc. motor) **Course:** Post. Cranial foss --\> mid cranial fossa --\> Cavernous sinus --\>superior orbital fissure **Branches:** Superior & Inferior Division **Components**: Somatic motor & parasympathetic Ganglion: Ciliary **Distribution:** All eye muscles except Superior Oblique and Lateral Rectus **Function:** eye movements, 2 smooth muscles \*\*\*sympathetics from symp. trunk travel w/ III to reach eye

Question 26

What nerve and type of nerve synapses in cilliary ganglion?

Answer 26

Parasympathetic of III * all other nerves pass through cilliary ganglion but **do not synapse**

Question 27

Trochlear Nerve (IV)

Answer 27

**Origin:** Trochlear Nucleus **Course:** Middle cranial fossa --\> Cavernous sinus --\> Superior orbital fissure **Components:** Somatic motor **Ganglion**: [NONE] **Distribution:** Superior Oblique muscle **Function:** Eye movement **\*\*\*\***is only cranial nerve to emerge from brainstem...longest intracranial course and susceptible to damage from blunt trauma

Question 28

Abducens (VI)

Answer 28

**Origin:** Pons **Course:** Post. cranial fossa --\> middle cranial fossa --\> cavernous sinus --\> SOF **Components:** Somatic Motor **Ganglion**: [NONE] **Distribution:** Lateral Rectus Muscle **Funciton:** Eye movement

Question 29

Structures of Superior Orbital Fissure

Answer 29

* **_Outside Tendinous Ring (Made by eye muscles)...*LOFT*_** * **L**acrimal of V1 * **O**pthalmic vein * **F**rontal of V1 * **T**rochlear (III) * _**Inside Tendinous RIng...*NC 36***_ * IV * VI * Nasocilliary of V1

Question 30

Layers of Eyeball

Answer 30

* Outer Layer * Sclera * Cornea * Middle Layer * Choroid * Cilliary Body * adjusts shape of lens * Iris * Retina

Question 31

Chambers of Eyeball

Answer 31

Question 32

Retina

Answer 32

* Optic Disc * location where blood vessels leave retina * blind spot; not rods/cones there * lighter than surrounding retina * Macula lutea * thinnest area of retina * few rods, more cones * highly sensitive to light * "yellow spot"

Question 34

Intrinsic Muscles of the Eye

Answer 34

* Ciliary Muscle * Constricts cilliary body * Innervated by III * Spincter pupillae * circularly arranged * innervated by III * constricts pupil * Dialator pupillae * radially arranged * innervated by sympathetics * dilates pupil