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Oculoplastics > Plastics anatomy > Flashcards

Plastics anatomy Flashcards

1
Q

Peripheral arterial arcade located where?

A

between Muller’s muscle and levator palpebrae superioris

located at the superior edge of tarsus

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2
Q

Marginal artery

A

located 3 mm SUPERIOR to the SUPERIOR eyelid margin

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3
Q

Ethmoid sinuses drain into…

A

Anterior/middle ethmoid drains into MIDDLE meatus
posterior ethmoid drains into SUPERIOR meatus

Ethmoid inflammation can –> orbital extension 2/2 ethmoidal vessels or by development of a subperiosteal abscess

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4
Q

Maxillary sinus drains via…

A

drains via the maxillary ostium into nose alongside the MIDDLE MEATUS

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5
Q

Frontal sinus drains via…

A

drains via the frontoethmoidal recess into the MIDDLE MEATUS

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6
Q

MIDDLE MEATUS receives from which sinuses

A

anterior/middle ethmoid air cells (the posterior ethmoid cells drain into SUPERIOR meatus)

also: maxillary sinus and frontal sinus

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7
Q

Sphenoid sinus drains into…

A

Sphenoethmoidal recess.

Blockage of this outflow with significant sphenoid sinus inflammation may damage the adjacent optic nerve.

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8
Q

nasolacrimal duct drains into…

A

inferior meatus

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9
Q

Orbital roof contains these important structures:

A

o. lacrimal gland fossa = orbital portion of the lacrimal gland
o. fossa for the trochlea = 5 mm behind superior nasal orbital rim
o. supraorbital notch = supraorbital vessels and the supraorbital nerve

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10
Q

dye disappearance test

A

most useful in cases with u/L obstruction of the lacrimal drainage system.

Fluorescein is instilled into both eyes and tear meniscus is observed at the slit lamp under cobalt blue light for 5 min.

POSITIVE = ABNORMAL (when decreased clearance of fluorescein after 5min; prblm in drainage system)

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11
Q

Jones I

A 
Jones I (physiologic)
fluorescein onto ocular surface and placing swab at the nose at 2 min and 5 min to see if lacrimal drainage system is intact

POSITIVE when normal
NEGATIVE when no dye recovered on cotton tip at inferior meatus
1/3 false-negative rate in normal

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12
Q

“Jones III”

A

ability to find fluorescein in nasal cavity post-DCR

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13
Q

Jones II

A

Jones II (nonphysiologic)
performed after Jones I. Excess fluorescein is removed from the conjunctival fornix.
saline is then irrigated through the lacrmal system with a cannula. Saline is then collected in the nose.

POSITIVE when normal
NEGATIVE when no dye recovered after lacrimal irrigation with saline

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14
Q

Widest part of the orbit

A

10 mm (1 cm) behind the anterior orbital rim

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15
Q

MCC of orbital cellulitis in kids/adults

A

contiguous sinus spread
cause of pre/postseptal MCC of cellulitis in kids
Before immunization, MCC was H. influenzae.

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16
Q

Ophthalmic artery branches

A

central retinal artery
short/long posterior ciliary arteries
extraocular muscle arteries

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17
Q

angular artery extension of…

A

extension of Facial artery 2/2 external carotid artery circulation
Need to AVOID when performing a dacryocystorhinostomy (DCR).

Angular artery is 8 mm behind the medial canthal tendon

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18
Q

distance from canaliculi to valve of Hasner

A

Ampulla - 2 mm vertical
canaliculus: 8-10 mm horizontal before getting to nasolacrimal sac

lacrimal sac: 12-15 mm

Average value: 23 mm from punctal to start of nasolacrimal duct

Nasolacrimal duct: 12 mm-15 mm

Total: 35 mm

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19
Q

vorrugator vs procerus vs frontalis wrinkles

A

Corrugator causes vertical wrinkles between the eyebrows. (corrugated roofs also have vertical “wrinkles”)

Procerus depresses the heads of the eyebrows and causes horizontal wrinkles just inferior to the heads of the eyebrows.

Frontalis causes forehead wrinkles.

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20
Q

tarsal drainage

A

Post-tarsal drainage is into the:

  • orbital veins
  • deeper branches of the anterior facial vein
  • pterygoid plexus.

Medial pretarsal tissues drain into the angular vein. Lateral pretarsal tissues drain into the superficial temporal vein.

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21
Q

Drainage into the meatus…

A

The sphenoethmoid recess is superior to the superior concha. The corresponding meatus is inferior to the concha. For example, the superior meatus is inferior to the superior concha.

The sphenoid sinus drains into the sphenoethmoidal recess.

The frontal, anterior and medial ethmoidal, and maxillary sinuses drain into the middle meatus.

The nasolacrimal duct drains into the inferior meatus.

The posterior ethmoidal sinus drains into the superior meatus.

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22
Q

cause of reflex tearing

A

The parasympathetic nervous system is primarily responsible for reflex tearing. The afferent pathway is sensation provided by the nasociliary branch of CN V1 (corneal sensation).

A parasympathetic pathway originating from the superior salivary nucleus of the pons makes its way to the lacrimal gland for the efferent pathway.

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23
Q

natural path of the nasolacrimal duct

A

After lacrimal sac, aim dorsal/caudal/LATERAL
Knowing the natural path of the nasolacrimal duct is crucial to avoid creating false pathways.

As you angle the probe upwards after feeling the hard stop of the bone in the lacrimal fossa, you want to advance the probe into the nasolacrimal duct. An easy way to remember that the duct travels laterally as you go down is to think about the same way that the nose is triangular and, in order to travel down the nose, you have to aim a bit laterally to point towards the nasal ala.

Similarly, if you think about the way that the punctum is in the frontal plane of the face and the valve of Hasner is in the inferior meatus inside the nose, it makes sense that you would have to advance the probe slightly posteriorly (dorsally) in order to stay in the nasolacrimal duct.

Again, thinking anatomically, as you advance the probe down the duct, you want to follow the contour of the nose as it widens at it’s base, and point slightly posteriorly (dorsally) because the valve of Hasner is a good way into the nose as compared to the eyelid.

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24
Q

Annulus of zin (oculomotor foramen)

A

The annulus of Zinn = circle overlying the superior orbital fissure and divides it into two. The area of the superior orbital fissure that is enclosed by the annulus of Zinn (called the oculomotor foramen) transmits CN III, CN VI, and the nasociliary branch of CN V1.
-Going anteriorly, the rectus muscles are connected by the intermuscular septum. This forms the intraconal space. All of the rectus muscles are innervated by nerves that stay in the cone and innervate the underbelly of the posterior 1/3 of the muscle.

Structures within the superior orbital fissure but outside of the area enclosed by the annulus of Zinn = lacrimal and frontal branches of CN V1, CN IV (trochlear), and the superior ophthalmic vein. Mnemonic LFTs (Lacrimal, Frontal, Trochlear).

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25
Q

tarsus @ what level and order?

A

Upper tarsus is about 10-12 mm in vertical height (the lower tarsus is about 4 mm in height). Both of the tarsus are about 1 mm thick.

Therefore, stabbing 14 mm from the margin will avoid the tarsus.

The sequential layers of the eyelid at this level are:

skin, orbicularis, orbital septum, orbital fat, levator, Muller’s muscle, conjunctiva

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26
Q

optic strut

A

The optic canal is SUPERIOR to the superior orbital fissure.

The optic canal is within the bone of the lesser wing of the sphenoid and is separated from the superior orbital fissure by the optic strut.

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27
Q

lower eyelid equivalent of levator

A

The capsulopalpebral fascia originates from the muscle fibers of the inferior rectus. It extends forward, wraps around the inferior oblique, and then inserts into the inferior tarsal border.

28
Q

length of optic nerve

A

Average length from the posterior globe to the optic foramen in an adult is 18 mm. The length of the orbital part of the optic nerve is 25-30 mm.

This difference in length allows the eye to rotate back and forth with eye movements and to move anteriorly (e.g. in proptosis) without damaging the nerve.

29
Q

damaged medial canthal tendon

A 
Anterior portion (of the medial canthal tendon): primarily responsible for the structural support of the eyelid
-if just the anterior portion is avulsed, it can be sutured to the anterior lacrimal crest (its natural position). 
Posterior portion (of the medial canthal tendon): primarily responsible for keeping the eyelid and punctum apposed to the globe. 
-if avulsed anterior AND posterior portions of the MCT  and the naso-orbital bone is NOT BROKEN, the avulsed tendon should be fixed to the posterior lacrimal crest by wire passed through small drill holes in the bone.

-if avulsed anterior AND posterior portions of the MCT and the naso-orbital bone is BROKEN =a metal miniplate should be fixed to the nasal bone and the avulsed tendon sewn to the miniplate (after the breakage in the bone is reduced).

30
Q

Whitnall’s tubercle

A

Whitnall’s tubercle is a helpful landmark in orbital surgery. The following five structures attach to Whitnall’s tubercle:

Lateral canthal tendon
Check ligament of the lateral rectus
Lateral horn of the levator aponeurosis
Lockwood's ligament
Whitnall's ligament
Understanding the orbital anatomy is an important consideration in eyelid surgery as often these attachments are anchor points for eyelid reconstruction.
31
Q

epiphora with only one functional cannaliculus?

A

with only one functional canaliculus:
10% of patients have constant epiphora
40% have intermittent epiphora

32
Q

You have probed a child’s valve of Hasner for congenital nasolacrimal duct obstruction 3 times. The 2-year-old is coming back with symptoms of nasolacrimal duct obstruction. What is the next best treatment for the child?

A

Silicone stents are good for patients with recurrent stenosis either in the canalicular system, lacrimal sac, or nasolacrimal duct.

They have a high success rate and are mildly invasive compared to DCR and CDCR.

33
Q

A conjunctivodacryocystorhinostomy (CDCR) starts and ends at what two structures, respectively?

A

A: caruncle and middle meatus

34
Q

A dacryocystorhinostomy (DCR) starts and ends at what two structures, respectively?

A

A: punctum to middle meatus

DCR creates passage by?
Middle turbinate
Near cribiform plate

35
Q

Jones tube starts/ends where?

A

The Jones tube starts at the caruncle and empties into the middle meatus.

36
Q

Gray line

A

Pretarsal orbicularis extends to the eyelid margin and is known as the muscle of Riolan. Its distinct color can be seen externally as the gray line.
Anterior to the tarsal plate.
Meibomian glands are posterior the gray line.

37
Q

Branches of V1

A

V1 ophthalmic branches into the NFL (nasociliary, frontal,lacrimal)

Nasociliary branches into the short and long ciliary nerves.
- long ciliary nerves supply the iris, cornea, and ciliary muscle.
-Prior to entering the globe, the nasociliary branch gives off branches that go through the anterior and posterior ethmoidal foramen to SUPPLY INNERVATION TO THE ETHMOID sinus, the lateral wall of the nose, and the tip of the nose’s skin.
Ex: HZV involvement of the tip of the nose may indicate that there is involvement of the nasociliary branch of V1. Since the the cornea is innervated by the nasociliary branch, this indicates a higher (though not absolute) risk of corneal involvement.

Frontal branches into the supratrochlear and supraorbital.

Lacrimal does not branch.

38
Q

Fat pads in the eyelids

A

There are three fat pads in the lower eyelid and two in the upper eyelid.
Knowing that the inferior oblique muscle separates the medial and central fat pads helps in avoidance of its cutting.

39
Q

Muller and levator attachment to tarsal plate

A

Muller’s muscle attaches at the SUPERIOR border of the tarsal plate. The levator attaches on the lower one half of the anterior part of the tarsal plate.

40
Q

Where does the orbital septum arise? Where does it fuse in Caucasians vs Asians?

A

Orbital septum arises from periosteum

In Caucasians, the septum fuses with the levator above the tarsal plate (2-5 mm above).
In Asians, the septum fuses with the levator between the superior border of the tarsal plate and the eyelid margin. This allows fat to occupy a lower position than in Caucasians and gives the eyelid a softer and more full appearance in addition to a lower eyelid crease.

41
Q

Lefort fracture

A

All Lefort fractures by definition involve the pterygoid bone.

A LeFort I is a low transverse maxillary fracture above the teeth with NO ORBITAL involvement.
KEY: A LeFort II involves the nasal, lacrimal, and maxillary bones as well as the MEDIAL orbital floor.
A LeFort III involves craniofacial disjunction in which the entire facial skeleton may be completely detached from the base of the skull and suspended by soft tissues.

42
Q

Medial canthal tendon

A

An upper and a lower limb fuse. Then the tendon splits into an anterior and posterior limb. The anterior and posterior limb go AROUND the lacrimal sac.
Anterior limb inserts on the anterior lacrimal crest
Posterior limb inserts on the posterior lacrimal crest.

43
Q

sinuses and the optic nerve

A

Optic nerve: just superior and lateral to the sphenoid sinus. The carotid artery runs just underneath the optic nerve at this point as it emerges from the cavernous sinus and forms an indentation on the posterior wall of the sphenoid sinus.
Pathologic processes forming inside the sphenoid sinus such as infection or a mass lesion can cause compression of the optic nerve.
ex: immunocompromised patients with pansinusitis extending into the sphenoid and optic nerve compression, consider Aspergillus infection

Frontal sinus sits well above and anterior to the optic nerve, although a large frontoethmoidal mucosal impinging on the orbit could cause a compressive neuropathy.

Ethmoid sinus sits anterior to the sphenoid sinus and is “on the way” to the optic nerve.
Ex: when performing an endoscopic medial wall decompression for thyroid disease, you will have to go through the anterior ethmoidal air cells and dissect back to the sphenoid sinus to get a proper posterior decompression to relieve tension on the optic nerve. In compressive optic neuropathy from TED, enlargement of the MR is usually most predictive of nerve compression. Thus, decompressing the medial wall to as posterior as possible is most beneficial for relieving compression.

The posterior wall of the maxillary sinus ends well before the optic nerve at the pterygopalatine fossa.

44
Q

upper eyelid crease from…

A

… levator attachment to skin and orbic

Just superior to the tarsus, the levator splits into two portions. One portion attaches to the orbicularis and skin to form the eyelid crease. The fold is created by an overhang of skin, orbicularis, and sometimes prolapsed orbital fat.

45
Q

What orbital wall has the least anterior-posterior length?

A

The orbital floor consists of the maxillary, palatine, and zygomatic bones. It forms the roof of the maxillary sinus and DOES NOT extend into the orbital apex unlike the other orbital walls.
Instead, the orbital floor ends at the pterygopalatine fossa. This makes it have the least anterior-posterior length.

46
Q

A properly done retrobulbar block will freeze all of the muscles but the…

A

… superior oblique (because the trochlear nerve is never in the cone).

47
Q

What are the bones comprising the lamina papyracea?

A

Ethmoid + Maxillary bones

48
Q

epiphora

A

The overflow of tears from the ocular surface down the cheek. Having the perception of “watery eyes” (i.e. “pseudoepiphora”) and having frank epiphora are two different things. Epiphora is associated with lacrimal drainage obstruction while “watery eyes” can be associated with other ocular/eyelid abnormalities (e.g. dry eyes). Epiphora is defined as overflow tearing.

49
Q

supraorbital notch & Lockwood’s ligament

A

The supraorbital notch is part of the orbital roof. Lookwood’s ligament supports the globe from below. The lateral wall is the strongest wall of the orbit.

50
Q

volume of the orbit

A

The adult orbit is pear-shaped with the “peak” of the pear corresponding to the orbital apex. The approximate volume of the orbit is 30 mL (cubic centimeters) – a fact that is asked ad nauseum on standard board exams.

51
Q

lateral rectus blood supply

A

Two factoids to remember about the lateral rectus circulation:

  1. Unlike the other 3 recti muscles, the lateral rectus only has one associated anterior ciliary artery.
  2. The lacrimal artery sends off a branch that forms the one anterior ciliary artery for the lateral rectus muscle. This artery feeds the anterior portion of the lateral rectus muscle and also the anterior segment.
52
Q

Lacrimal sac located between?

A

Lacrimal + Maxillary bones

53
Q

Where do orbital floor fractures usually occur?

A

Medially

54
Q

Bones of Medial wall

A 
(“SMEL”)
Maxillary
Lacrimal
Ethmoid
Sphenoid (lesser)
55
Q

Bones of Floor

A

(“Please Mop Z Floor”)
Maxillary
Palatine
Zygomatic

56
Q

Bones of Lateral wall

A

(“Z Great One”)
Zygomatic
Sphenoid (greater)

57
Q

Bones of Roof

A

“Front Less”
Frontal
Sphenoid (lesser)

58
Q

Where do muscles penetrate Tenon’s capsule?

A

10mm behind insertions

59
Q

Only muscles with contralateral innervation?

A

Superior rectus and superior oblique

60
Q

Larges arc of contact & shortest tendon?

A 
Inferior oblique (encircled by capsulopalpebral fascia)
Injury causes pupil changes because parasympathetics run along IO
61
Q

Only muscle not supplied by ophthalmic artery?

A

Lateral rectus (from lacrimal artery)

62
Q

Only muscle with innervation outside cone?

A

Superior oblique (retrobulbar block rarely affects SO)

63
Q

Muscle most likely to result in oculocardiac reflex if pulled?

A

Medial rectus

64
Q

Basic secretion test

A

Tear production
Following topical anesthesia, measure filter paper at 5min
Normal?
>5mm

65
Q

Schirmer I

A 
No topical anesthesia
Measures basic and reflex tearing
Measure filter paper at 5min
Normal?
>10mm
66
Q

Schirmer II

A 
No topical anesthesia
Measures reflex tearing
Use cotton tip to irritate nasal mucosa
Measure filter paper at 5min
Normal?
>15mm
67
Q

Lacrimal anatomy

A

Lacrimal system dimensions?
2-8-10-12 mm

Valve at the beginning?
Rossenmuller

Valve at the end?
Hasner

Empties under which turbinate?
Inferior turbinate

Oculoplastics (4 decks)

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