Week 1 - B - Day 1, Afternoon Instant Anatomy Tutorial

Question 1

What are the two parts of the orbicularis oculi?

Answer 1

Orbital part and Palpebral part (eyelid)

Question 2

What lies immediately posterior to the orbicularis oculi muscle? Before even reaching the conjunctivae

Answer 2

The orbital septum

Question 3

What are the layers of the eyelid?

Answer 3

skin subcutaneous tissue orbicularis oculi orbital septum and tarsal plates, palpebral conjunctiva

Question 4

Which layer of the eyelid has the glands that produce the oily/lipid part of tears?

Answer 4

The tarsal plates - produce meibum

Question 5

Inflammation posterior to the orbital septum is sight threatening What is this known as?

Answer 5

Oribital cellulitis (opposite = preseptal cellulitis)

Question 6

The inner surface of the eyelids is covered by the palpebral conjunctiva. What is the type of conjuctivae lining the eyeball known as?

Answer 6

Known as bulbar (ocular) conjunctivae

Question 7

Bulbar conjunctiva

Answer 7

• mucous membrane covering ant surface of eyeball around cornea
• stratified epithelium containing goblet cells
• reflects onto inner eyelids (palpebral conjuctiva)

Question 8

The palpebral part of the orbicularis oculi is involved in normal blinking. What is the orbital part involved in?

Answer 8

Closing the eyes tightly

Question 9

What muscle assists the levator in elevating the top eyelid. It receives sympathetic innervation which may be compromised in Horners syndrome causing ptosis?

Answer 9

Muller’s muscle (superior tarsal muscle)

Question 10

Name the different coloured bones that contribute to the orbit of the eye?

Answer 10

Red - frontal Purple - maxilla Blue - zygoma Green - lacrimal Beige - ethmoid Yellow - sphenoid

Question 11

Which bone of the floor of the cranial cavity is the superior orbital fissue located in?

Answer 11

It is located in the sphenoid bone

Question 12

What are the three way for structures to enter the orbital cavity?

Answer 12

Optic canal Superior orbital fissue Inferior orbital fissure

Question 13

What does the Superior orbital fissure transmit into the orbit?

Answer 13

Oculomotor nerve (III) Trochlear (IV) Lacrimal/frontal/nasociliary branches of Ophthalmic nerve (V1) Abducent nerve (VI) Superior ophthalmic vein

Question 14

What branch comes of the ophthalmic nerve (CN V1) to innervate the upper half of the nasal cavity?

Answer 14

The anterior ethmoidal nerve

Question 15

The tear has three layers How does the tear film have antibacterial properties?

Answer 15

It has lysozymes - they are found in phagocytes and produce enymes to digest bacteria

Question 16

What are the three layers of the tear film?

Answer 16

Outer - Oil (lipid) layer - due to the meibum produced by the tarsal (meibomian) glands Middle - Water (aqueous) layer Inner - Mucin layer

Question 17

Which layer of the tear film contains the lysozymes? The lysozymes are part of the fluid produced by lacrimal gland

Answer 17

The aqeuous layer

Question 18

Tears have a basal and reflex secretion What is required for the reflex tear production?

Answer 18

An intact trigeminal nerve

Question 19

What nerve is for snesation when the eye needs tears? What nerve provides the parasympathetic supply to the lacrimal gland to produce tears?

Answer 19

CN V for sensation The CN VII - facial nerve via the greater petrosal nerve

Question 20

The palpebral conjunctiva is more vascular than the bulbar What can be seen on the palpebral conjuctivae?

Answer 20

Follicles and papillae can be seen on the palpebral conjunctiva

Question 21

What does the palpebral conjunctivae contain that secretes part of the tear film?

Answer 21

Contains goblet cells which secrete the mucin (inner layer of tear)

Question 22

Epithelium bowman’s membrane stroma Descemet’s membrane endothelium What are these the 5 layers of?

Answer 22

The five layers of the cornea

Question 23

How does the endothelium maintain transparency of the cornea?

Answer 23

Maintains transparency by pumping fluid out of the stroma

Question 24

What can happen to the endothelium if pressure in the eye goes up?

Answer 24

The endothelium will not function properly causing misty vision in the eye as there is a fluid build up

Question 25

What age does the lens of the eye start deteriorating causing cloudy vision?

Answer 25

At 23 years of age Condition known as cataracts

Question 26

Cataracts happen when protein builds up in the lens of your eye, making it cloudy. This prevents light from passing clearly through the lens, causing some loss of vision. New lens cells form on the outside of the lens, and the older cells are compacted into the center of the lens, forming the cataract. Catarcts is due to the lens not being able to rid of the old cells quick enough

Answer 26

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Question 27

How is the lens attached to the ciliary body?

Answer 27

Zonules attach to the suspensory ligaments of the lens

Question 28

What is the vascular layer supplying blood and nutrition to the eyeball?

Answer 28

The choroid (uvea)

Question 29

What is produced by the filtration of blood in the capillary network of the ciliary processes?

Answer 29

Aqueous humour

Question 30

Where does the aqueous humour flow from?

Answer 30

The aqueous humour flows from the posterior chamber to the anterior chamber of the eye - this sits in front of the iris but behind the cornea

Question 31

What makes the aqueous humour allow for good optical clarity?

Answer 31

Its low protein content

Question 32

What is inflammation of the middle layer of the eye known as?

Answer 32

Uveitis = Different autoimmune conditions can cause uveirits Can be part of reiters arthritis - uveitis, reactive arthritis, ureithritis

Question 33

What tumour of the apex of the long can cause Horner’s syndrome? What are the four signs of horner’s syndrome?

Answer 33

Pancoast tumour Ptosis - drooping of eyelid Miosis - constricted pupil Enopthalmos - sunken eye Annhydrois - lack of facial sweating

Question 34

Distant vision- lens is flatter so the refraction is less and can see further images, ciliary muscles are relaxed What is the accomodation reflex from seeing something from far to close?

Answer 34

• When changing from looking far to close, the ciliary muscles contract, thus the zonule fibres are relaxed and the lens becomes wider - having a greater refraction and seeing things that are closer
• Also bilateral conversion of the eyes
• Also sphincter pupillae contract

Question 35

What happens to the ability to accomodate as we get older? What are zonule fibres also known as?

Answer 35

Ability to accomodate decreases Zonule fibres also known as supensory ligaments of the lens

Question 36

What is the third cranial nerve? What extra-ocular muscles does it supply? What does a palsy of the third nerve look like?

Answer 36

Oculomotor - supplies inferior oblique, superior, medial and inferior rectus Palsy has the eye pointing down and out as the trcohlear nerve supplying the superior oblique still works Also the person will have ptosis, fixed dilated pupil (parasympathetics to constrictor muscles of eye dont work)

Question 37

The trochlear nerve is unique in that it arises from the dorsal aspect of the brainstem and crosses over If their is a left trochlear palsy, what muscle will have a pasly?

Answer 37

The muscle on the contralateral side so the right superior oblique muscle

Question 38

• eyes look upwards, vertical diplopia, cannot look down and out head held tilted. What nerve palsy is this? Why is there a head tilit?

Answer 38

Fourth nerve palsy To compensate for the double-vision resulting from the weakness of the superior oblique, patients characteristically tilt their head down and to the side opposite the affected muscle * ie if Right SO palsy, patients head will tilt left

Question 39

The trochlear nucleus lies below the cerebral (sylvian) aqueduct This is in the brainstem How does the nerve enter the eye?

Answer 39

The nerve enters the eye through the superior orbital fissure in the sphenoid bone

Question 40

What conveys the sensory (afferent) arm of the blink (corneal) reflex?

Answer 40

The opthalmic division of the trigeminal nerve

Question 41

horizontal diplopia, eyes medially deviated, & cannot move laterally from midline. COnvergent squint (start in) What nerve is this due to and how does the horiontal diplopia work?

Answer 41

Due to the CN VI (abducent) Controls the lateral rectus and therefore the eyes will not be centrally focussed causing different images on the horizontal plane

Question 42

The 6th nerve passes through the middle of the cavernous sinus, not the wall What are the other nerves of the carvernous sinus? What is the artery? (O TOM CA)

Answer 42

• Oculomotor
• Trochlear
• Opthalmic
• Maxillary
• Abducent
  
  • Internal Carotid artery

Question 43

Usually the nasociliary branch of the opthalmic division of the trigeminal nerve supplies the tip of the nose What sign is Vesicles on the tip of the nose, or vesicles on the side of the nose? What does it tell you?

Answer 43

It is called Hutchison’s sign Tells you the eye has been affected as it has gone past the ophthalmic nerve

Question 44

The muscles are attached to a common tendinous ring at the back of the eye What nerve and artery travels in the middle of this ring? Which extraocular muscles are located outside the tendinous ring?

Answer 44

Optic nerve alongisde the opthalmic artery The levator palpabrae superioris, the superior oblique and also inferior oblique as this attaches to the maxilla Only the 4 rectus muscles are attached to the common tendinous ring

Question 45

The optic nerve sheath is attached to the common tendinous ring, why optic neuritis causes pain on eye movements What muscle is commonly trapped in a blow out fracture of the orbit?

Answer 45

The inferior rectus muscle

Question 46

The retina have rods and cones Where are rods not found? Where are cones found in the highest density?

Answer 46

rods are found everywhere in the retina, except in and near the fovea. Cones are found in highest density in the fovea

Question 47

What is the end artery supplying the eye? An emboli that lodges hear can cause loss of vision

Answer 47

The opthalmic artery is the end artery supplying the eye

Question 48

What is the back of the eye known as? In fundoscopy what region of the eye do the quadrants go through?

Answer 48

The fundus Thq quadrants go throug the fovea of the eye

Question 49

The superior ophthalmic vein leaves the eye via the Superior orbital fissure The vein drains into the cavernous sinus Why do retinal veins appear thicker than the retinal arteries?

Answer 49

Retinal veins appear thicker than retinal arteries due to arteries having a muscular tunic

Question 50

The cornea has a rich supply of free nerve endings The long and short ciliary nerves become part of the nasociliary nerve of the trigeminal - sensory of cornea What is the branch of the nasociliary nerve entering the nasal cavity via the anterior ethmoidal foramen?

Answer 50

The anterior ehtmoidal nerve

Question 51

Retinal detachment occurs when the thin lining at the back of your eye called the retina begins to pull away from the blood vessels that supply it with oxygen and nutrients. What people is retinal detachment more common in?

Answer 51

More common in people with short sight as they have big eyes

Question 52

The inferior wall of the orbit is the most vulnerable to blunt trauma People with inferior wall fracture often complain upon pain on upgaze due to which muscle being trapped?

Answer 52

The inferior rectus muscle

Question 53

Rods are involved in seeing in dim light and peripheral vision What type of vision can loss of peripheral vision result in?

Answer 53

Tunnel vision

Question 54

Age-related macular degeneration (AMD) is a painless eye condition that causes you to lose what?

Answer 54

Causes you to lose central vision usually in both eyes