Anatomy of the Orbit - Double check for all details

Question 1

Name 3 sinuses within the skull

Answer 1

1) Frontal sinus

2) Ethmoid sinuses

3) Maxillary sinuses

Question 2

Describe the orbital septum and its attachments

Answer 2

Extension of periosteum in upper and lower eyelid

Tendon of levator palpebrae attaches to it in upper eyelid

Tarsus attaches to it in lower eyelid

Question 3

Describe position of the conjunctiva

Answer 3

Covers inside of eyelid and outside of eyeball

Question 4

Define superior and inferior tarsus of the eye

Answer 4

Dense connective tissue attached to the orbit via palpebral ligaments

Provides support for each eyelid

Contain modified sebacceous glands

Question 5

Where does the levator palpebrae superiorus act?

Answer 5

It pulls up the superior tarsus with help from superior tarsal smooth muscles

Question 6

Describe motor innervation of the eyelid

Answer 6

Facial nerve helps close orbicularis oris

Oculomotor nerve innervates levator palpebrae superiorus to hold the eyelid open

**Postganglionic Sympathetic Fibers innervate the superior tarsal muscle to hold the eyelid open **

Question 7

Define Ptosis

Answer 7

Drooping of the eyelid

Question 8

Describe movement of tears

Answer 8

Produced in lacrimal gland at superior lateral corner of eye

Moves across eye to inferior medial corner and into lacrimal canaliculi

Lacrimal canaliculi join into the lacrimal sac

Lacrimal sac drains with blinking into the inferior meatus of the nasal cavity

Question 9

What innervates the lacrimal gland? Describe pathways

Answer 9

1) Lacrimal branch of Ophthalmic branch of Trigeminal Nerve

2) Parasympathetic Preganglionic nerve fibers of greater petrosal nerve continue as the nerve of the pterygoid canal, which continues as pterygopalatine ganglion, which enter into maxillary nerve, eventually reach into zygomaticotemporal branch to reach lacrimal gland

3) Sympathetic nerve fibers originate in the superior cervical ganglion, follow blood vessels to reach the head, form the deep petrosal nerve prior to joining the nerve of the pterygoid canal, which continues THROUGH the pterygopalatine ganglion, which enter into maxillary nerve, eventually reach into zygomaticotemporal branch to reach lacrimal gland

Question 10

List extraocular muscles

Answer 10

Levator Palpebrae Superiorus

Superior oblique

Superior rectus

Medial rectus

Lateral Rectus

Inferior Rectus

Inferior Oblique

Question 11

Which two extraocular muscles always work in conjunction?

Answer 11

**The superior oblique and the medial rectus **

Question 12

Which muscle helps you look downward and medially?

Answer 12

Superior oblique (with help of medial rectus)

Question 13

Which muscle helps you look upward and medially?

Answer 13

Inferior oblique

Question 14

What muscle helps you look laterally and upward? laterally and downward?

Answer 14

Lateral and upward = Superior rectus

Lateral and downward = Inferior rectus

Question 15

Name 3 major arteries of the eyeball

Answer 15

Lacrimal artery

Central Artery of the Retina

Long and Short Ciliary Arteries

Question 16

What are 2 venous channels of the orbit?

Answer 16

Superior Ophthalmic Vein

Inferior Ophthalmic Vein

Question 17

Describe how the extraocular muscles are innervated by which cranial nerves.

Answer 17

Abducens innervates lateral rectus (“make your eyes abduct”)

Trochlear innervates superior oblique (“so small you start to cross your eyes”)

Oculomotor innervates everything else (levator palpebrae, superior rectus, medial rectus, inferior rectus, inferior oblique)

Question 18

Name 3 branches of ophthalmic branch of trigeminal nerve

Answer 18

1) Lacrimal Nerve

2) Frontal Nerve

3) Nasociliary Nerve

Question 19

What is the parasympathetic ganglion of the oculomotor nerve?

Answer 19

Ciliary ganglion