506: The Eye & Orbit

Lateral canthus

Identify the structure at #1

Palpebrae (eyelid)

Identify the structure at #2

Bulbar conjunctiva

Identify the structure at #3

Border between sclera & cornea

Identify the structure at #4

Lacrimal lake

Identify the structure at #5

Caruncle

Identify the structure at #6

Medial canthus

Identify the structure at #7

Palpebral conjunctiva

Identify the structure at #8

Fornix

Identify the structure at #9

Pupil

Identify the structure at #10

Iris

Identify the structure at #11

Ophthalmic (V1)

- Supraorbital n.

- Supratrochlear n.

Identify the dermatome in yellow. What nerve(s) participate in this sensation?

Maxillary (V2)

- Infraorbital n.

Identify the dermatome in red (middle). What nerve(s) participate in this sensation?

Mandibular (V3)

Identify the dermatome in peach (bottom)

lacrimal n.

frontal n.

nasociliary n.

what are the 3 main branches of the opthalmic branch (V1) of CN V?

frontal n.

the supraorbital n. is a branch of the:

frontal n.

the supratrochlear n. is a branch of the:

Frontal n.

What ophthalmic division provides sensory to the forehead and scalp?

Lacrimal n.

What ophthalmic division provides sensory to the lacrimal gland and upper eyelid?

Nasociliary n.

What ophthalmic division provides sensory to the medial orbit and upper nose?

Supratrochlear n.

Identify the structure at #1

Supraorbital n.

Identify the structure at #2

Nasociliary n.

Identify the structure at #3

Frontal n.

Identify the structure at #4

Medial & lateral branches of supraorbital n.

Identify the structure at #5

Lacrimal n.

Identify the structure at #6

Superior orbital fissure

Identify the structure at #7

Lacrimal n.

Identify the structure at #1

Nasociliary n.

Identify the structure at #2

Frontal n.

Identify the structure at #3

Anterior & posterior ethmoidal n.s

Identify the structure at #4

Supraorbital n.

Identify the structure at #5

Supratrochlear n.

Identify the structure at #6

Infratrochlear n.

Identify the structure at #7

External nasal branch (from anterior ethmoidal)

Identify the structure at #8

Infraorbital n. (from V2)

Identify the structure at #9

anterior ethmoidal n.

posterior ethmoidal n.

what are the two branches of the nasociliary n.?

nasociliary n.

the anterior ethmoidal n. is a branch of the:

nasociliary n.

the posterior ethmoidal n. is a branch of the:

anterior ethmoidal n.

the external nasal n. branch is a branch of the:

V2

the inferior eyelid's sensory innervation comes from:

V1

the superior eyelid's sensory innervation comes from:

nasociliary n.

which branch of V1 is the only nerve that supplies the sensory info to the eyeball?

obicularis oculi m. (orbital & palpebral parts)

identify the structure:

medial palpebral ligament

identify the structure (red arrow):

lateral palpebral ligament

identify the structure:

- Support for eyelids (eyelid skeleton)

- Anchors tarsal muscles

- Contains tarsal glands

Function of the tarsal plates:

Tarsal plates

Identify the structure:

CN VII to the orbicularis oculi (palpebral part)

motor control for the blink reflex is done by:

V1, nasociliary n.

sensory innervation to activate the blink reflex triggered by touch is done by:

CN II

sensory innervation to activate the blink reflex triggered by visual threat or bright light is done by:

CN VIII

sensory innervation to activate the blink reflex triggered by sudden sounds (>50-60 dB) is done by:

frontal

maxilla

zygomatic

lacrimal

ethmoid

sphenoid (greater and lesser)

name the 6 bones that make up the orbit:

Optic canal

Identify the structure at #1

Supraorbital foramen

Identify the structure at #2

Posterior ethmoidal foramina

Identify the structure at #3

Anterior ethmoidal foramina

Identify the structure at #4

Superior orbital fissure

Identify the structure at #5

Inferior orbital fissure

Identify the structure at #6

Infraorbital groove

Identify the structure at #7

Infraorbital foramen

Identify the structure at #8

Frontal

Identify the structure at #1

Ethmoid

Identify the structure at #2

Lesser wing of sphenoid

Identify the structure at #3

Greater wing of sphenoid

Identify the structure at #4

Zygomatic

Identify the structure at #5

Maxilla

Identify the structure at #6

Lacrimal

Identify the structure at #7

Orbital floor & infraorbital canal (maxilla)

Identify the structure at #1

Orbital plate of ethmoid bone (lamina papyracea)

Identify the structure at #2

superior orbital fissure

V1 enters the orbit via the:

frontal bone

the supraorbital foramen is located on the:

Ethmoid air cells

Identify the structure at #1

maxilla bone

the infraorbital foramen is located on the:

Sphenoid sinus

Identify the structure at #2

Maxillary sinuses

Identify the structure at #3

orbital blowout fracture

what is the diagnosis?

- diplopia (occurs if both eyes don't track equally)

- infraorbital nerve damage (facial numbness)

- infections

What are the complications of an orbital blowout fracture?

The inferior rectus disrupts the infraorbital groove (usually into the maxillary sinus but could go into ethmoid sinus)

What muscle is involved with an orbital blowout fracture?

Special sensory only

What type of nerve is the optic nerve (CN II)?

Dura mater

Arachnoid mater

Pia mater

What meninges surround the optic "nerve"?

Forebrain

Optic tracts are an extension of the:

Hydrocephalus

High CSF pressure:

Vision problems due to swelling of optic disc

Symptoms of hydrocephalus:

Subarachnoid space

Identify the structure at #1

Optic disc

Identify the structure at #2

CSF

what causes the pressure exerted on the optic nerve in papilledema?

papilledema (usually bilateral - if unilateral, likely indicative of ocular pathology, e.g. optic nerve glioma)

patient presents with bilateral blurred vision. An eye exam was done and displays bulging of the optic disc. What is the diagnosis?

anterior (to equator)

the rectus muscles of the eye insert onto the eyeball on the _______ aspect

posterior (to equator)

the oblique muscles of the eye insert onto the eyeball on the _______ aspect

superior rectus m.

identify the structure:

medial rectus m.

identify the structure:

inferior rectus m.

identify the structure:

lateral rectus m.

identify the structure:

superior oblique m.

identify the structure:

inferior oblique m.

identify the structure:

levator palpebrae superioris m.

identify the structure:

Levator palpebrae superioris

What muscle elevates the upper eyelid?

Superior oblique

Identify the structure at #1

Superior rectus

Identify the structure at #2