Eye And Ear Anatomy

Front 1

What is a blow out fracture?

Back 1

When you fracture the maxilla --> the globe will drop down into the maxillary sinus

Front 2

What bones make up the roof of the orbit?

Back 2

Frontal and sphenoid

Front 3

What bones make up the lateral wall of the orbit?

Back 3

Zygomatic sphenoid

Front 4

What bones make up the medial wall of the orbit?

Back 4

Ethmoid, sphenoid, maxilla, lacrimal

Front 5

What bones make up the floor of the orbit?

Back 5

Maxilla, zygomatic and palatine bones

Front 6

What goes through the optic canal?

Back 6

The optic nerve (II) and opthalmic artery

Front 7

What goes through the superior orbital fissure?

Back 7

Nerves III (occulomotor), IV (trochlear) V1 (opthalmic branch of trigeminal) and VI (abducent)
Also the opthalmic vein

Front 8

What goes through the inferior orbital fissure?

Back 8

V2 nerve. Then it will come back out lower down to give sensory innervation to middle part of the face

Front 9

What innervates the external ear?

Back 9

V2 and C2-3

Front 10

What two things make up the external ear?

Back 10

External acoustic meatus and the auricle

Front 11

What is the function of the auricle?

Back 11

Protects the ear and helps localise sound

Front 12

What is the external acoustic meatus' structure?

Back 12

Cartilage on outside then bone as you get more inside.
Lateral part has sebaceous and cerumious glands as well as hairs

Front 13

Function of external acoustic meatus

Back 13

Humidifies the air (the wax and sebaceous glands) so it's perfect for the middle ear environment
Protects middle ear from bugs etc
Conducts sound inwards and maybe amplifies it

Front 14

Where is the pars flaccida?

Back 14

Top little bit of the tympanic membrane (top 1/4 or so)

Front 15

Where is pars tensa?

Back 15

Bottom 3/4 of the tymp membrane

Front 16

What makes up the middle ear?

Back 16

Tymp mem, the ossicles, muscles, ear cavity

Front 17

What covers the surface of the tympanic membrane?

Back 17

Different on each side:
- outer surface = covered in skin
- inner surface = continuous with the mucus membrane in the ear canal

Front 18

What innervates the tympanic membrane?

Back 18

- outer surface = V3 and vagus
- inner = glossopharyngeal (IX)

Front 19

What are the names of the three ossicles?

Back 19

MALLEUS - attaches to the tympanic membrane then to the INCUS which attaches to the STAPES - closes the oval window

Front 20

What is the stapes?

Back 20

One of the ossicles. it closes the oval window --> transmits vibrations into the cochlear

Front 21

What type of joints are between the ossicle bones?

Back 21

Synovial joints

Front 22

What are the two muscles in the middle ear and what are their functions?

Back 22

Tensor tympani - comes from the auditory canal to the malleus.
Stapedius - connects to the stapes
They contract when sound is loud so we don't get too much vibration of the bones - protects the ear

Front 23

What is the tensor tympani and what's it innervated by?

Back 23

V3 (like TVP - all three tensor muscles are innervated by V3!!)
When tymp mem vibrates, reflex goes to tensor tympani --> it contracts so the malleus won't vibrate as much ie dampens down the vibrations

Front 24

What is hyperacusis? What nerve lesions would cause it?

Back 24

You're extremely sensitive to excessive noise
lesions in V3 and VII would cause it

Front 25

What innervates stapedius muscle?

Back 25

VII

Front 26

What is the roof of teh middle ear cavity?

Back 26

the tegmen tympani bone - very thin --> if you have an infection, it can break through into the meninges etc

Front 27

Where does the auditory tube go to and from?

Back 27

From the middle ear cavity to the nasopharynx

Front 28

What are the osseous and membranous labyrinths?

Back 28

They make up the internal ear.
osseous are the cavities in bone that house the membranous labyrinth

Front 29

What are the three parts of teh osseous labyrinth? What sort of fluid is in here?

Back 29

- Semi-circular canals
- Vestibule
- Cochlea
Filled with perilymph

Front 30

What are the three parts of the membranous labyrinth? What sort of fluid is here?

Back 30

- Semi-circular ducts
- Saccule and Utricle
- Cochlea

Front 31

What is the 'kinetic labyrinth'?

Back 31

The semicircular ducts
They detect angular movement eg going around a corner

Front 32

How do the semicircular ducts detect movement?

Back 32

Little hairs are embedded in the cupula of the ducts. When the endolymph moves around, they will detect the movement

Front 33

What is the 'static labyrinth'?

Back 33

The utricle and saccule
They detect stationary balance

Front 34

What fluid is in the semicircular canals and in the ducts?

Back 34

Canals - perilymph (very similar to CSF)
Duct - endolymph

Front 35

What is the structure of the cochlea duct?

Back 35

Has 2 1/2 turns. The oval window is at one end. The Organ of Corti is in it --> detects the sound

Front 36

What is the organ of corti?

Back 36

sensory organ of hearing

Front 37

What is the difference between conductive and sensorineural hearing loss?

Back 37

conductive - the receptors are ok but vibrations aren't travelling through the ear properly
sensorineural - the receptors aren't working or the nerve that transmits the information up to the brain

Front 38

What is the Rinne test?

Back 38

Mastoid process (bone conduction ie skipping the middle ear) then in front of the ear (air conduction)
normal person has better air conduction than bone

Front 39

What results from Rinne test would someone with conductive hearing loss have?

Back 39

Bone would be better - their receptors are fine
Bone transmission --> you're skipping their faulty middle ear area

Front 40

What results would someone with sensorineural hearing loss have in the Rinne test?

Back 40

Neither would be good

Front 41

What is the Weber test?

Back 41

Hold tuning fork in the middle of their skull and ask which side sounds best

Front 42

What results in Weber test would someone with conductive hearing loss have?

Back 42

They would hear BETTER in the BAD ear - because this is testing bone conduction --> skipping their dud middle ear

Front 43

What results in Weber test would someone with sensorineural hearing loss have?

Back 43

Better in the good ear

Front 44

What is the sensory innervation to the tympanic membrane?

Back 44

Outside = V3 and C2-3
Inside = glossopharyngeal

Front 45

What innervates the muscles in the middle ear?

Back 45

Tensor tympani - V3
Stapedius - facial nerve

Front 46

What fluid is in the osseous and membranous labyrinths?

Back 46

Perilymph in osseous
Endolymph in membranous

Front 47

What is the difference in what the semicircular ducts detect compared to the utricle and saccule?

Back 47

Ducts --> rotational head movements ie kinetics
The utricle and saccule are linear accelerations / more just your position in space
the notes just say that canals are kinetic, utricle and saccule are static

Front 48

Roof of orbit

Back 48

Frontal and sphenoid

Front 49

Medial wall of orbit

Back 49

Ethmoid, sphenoid, lacrimal and maxilla

Front 50

Lateral wall of orbit

Back 50

Sphenoid and zygomatic

Front 51

Floor of orbit

Back 51

Maxilla, zygomatic and palatine

Front 52

What goes through SOF?

Back 52

III - occulomotor
IV - trochlear
V1 - opthalmic (sensory)
VI - abducent
And the opthalmic vein

Front 53

What goes through IOF?

Back 53

V2

Front 54

What goes through optic fissure?

Back 54

Optic nerve and opthalmic artery

Front 55

What do the tarsal glands secrete? Where are they located?

Back 55

Oily substance that stops the tears from overflowing out of the eye
In the tarsal plates in the eyelid

Front 56

What muscle lifts the eyelid? What's it innervated by?

Back 56

LPS
INnervated by III occulomotor

Front 57

What is a sty?

Back 57

When the tarsal glands get blocked and swell up

Front 58

Where are tears produced?

Back 58

Lacrimal gland

Front 59

What innervates the lacrimal gland?

Back 59

Facial via PpG

Front 60

What are the two parts of the lacrimal gland?

Back 60

Palpebral (more anterior) and orbital (more posterior)

Front 61

How do the tears get collected from the eye

Back 61

Drain into lacrimal canals first
Then into lacrimal sac
Then down the nasolacrimal duct and into the nasal cavity

Front 62

What are two parts of external tunic?

Back 62

Sclera and the cornea

Front 63

What is the lamina cribrosa?

Back 63

Sievelike structure at the back of the sclera through which the optic nerve leaves the eye

Front 64

What is the canal of schlemm?

Back 64

Part of the sclera
it drains the fluid from aqueous humour
If it gets blocked, have problems ie it's very important

Front 65

What's the corneal reflex

Back 65

Touch - sensed by V1
Response - close eye = facial nerve

Front 66

What nerve is sensory to the eye?

Back 66

V1

Front 67

What makes up the middle tunic?

Back 67

The choroid, ciliary body and the iris

Front 68

How tight are the attachments between sclera, choroid and retina

Back 68

Retina is tightly attached to choroid
Then choroid - sclera isn't as tight of an attachment

Front 69

What is the function of the choroid?

Back 69

It supplies blood to the outer parts of the retina (it is supplied by the ciliary artery - branched off the opthalmic artery)
And it absorbs some light

Front 70

How does the retina get blood supply?

Back 70

The opthalmic artery has two branches: the ciliary artery which provides blood to the choroid (among other things) and the choroid nourishes the outer part of the retina
THe other branch is the central retinal artery - this supplies blood to the centre of teh retina

Front 71

What is the ciliary body?

Back 71

It contains the ciliaris muscle - attached to lens via suspensory ligaments --> changes the shape of the lens
The ciliary body also produces the aqueous humour

Front 72

What muscles are acting on the iris?

Back 72

Sphincter pupillae --> constricts the pupil. Parasymp innervation
Dilator pupillae --> dilates it. Symp innervation

Front 73

What control (para or symp) are the dilator and sphincter pupillae muscles under?

Back 73

Sphincter - makes it smaller --> para
Dilator - makes it wider - good for running away from tigers --> symp innervation

Front 74

Why are albino's pupils red?

Back 74

They don't have pigment in their choroid --> just have the rich blood vessel plexus there
Our pupils appear black because of all the pigment on the choroid

Front 75

What is the pupillary reflex?

Back 75

Shine light - detected by optic
Then the sphincter pupillae will close - innervated by occulomotor
Get constriction of BOTH pupils (direct and consensual responses)

Front 76

How do we get glaucoma?

Back 76

Build up of pressure in the orbit

Front 77

What are the two types of glaucoma?

Back 77

oepn angle - the iridocorneal angle is normal, it's the meshwork at the back of the canal of schlemm that's blocked up and causing teh build up of pressure
Closed angle - the canal itself is fine but it's being closed off by the iridocorneal angle

Front 78

What is the macula lutea?

Back 78

Area on the retina with very high density of receptors

Front 79

What is the blind spot?

Back 79

Area on the retina where the optic nerve leaves the eye --> no receptors here

Front 80

what is the aqueous humour?

Back 80

It's at the front of the eye
Contains glucose, amino acids and ascorbic acid
Nourishes avascular stuff in the eye and maintains good intraocular pressure
It gets drained by the canal of schlemm - if it's not getting drained properly, have build up of pressure --> glaucoma

Front 81

What is the vitreous humour?

Back 81

Contains water, salts and glycoprotein
Further back in the eye
It supports the lens and retina and magnifies the lihgt

Front 82

What happens for LONG DISTANCE SIGHT?

Back 82

Want the lens stretched out.
The ciliaris muscle relaxes --> pulls the suspensory ligaments --> pulls the lens

Front 83

How do we get SHORT distance sight?

Back 83

Want fat lens
Ciliaris muscle contracts --> suspensory ligaments are less tight --> the lens can be fatter and looser

Front 84

Movements of the SR?

Back 84

elevate, adduct and intort

Front 85

Movements of the IR?

Back 85

depress, adduct and extort

Front 86

How do you test just the superior rectus?

Back 86

Get them to put their eye in the abducted position ie get the axis of the muscle in line with the axis of the globe. THen look up

Front 87

Movements of SO?

Back 87

depress the eye, abduct and intort

Front 88

Movement of MR

Back 88

Adduction of the eye

Front 89

How do you test SO alone?

Back 89

Get them to adduct their eye and then look down

Front 90

How does the opthalmic artery enter the orbit?

Back 90

Through the optic fissure

Front 91

How does the opthalmic vein enter the orbit?

Back 91

SOF

Front 92

What are the two branches of opthalmic artery and what do they supply?

Back 92

Ciliary artery - supplies the choroid (which will supply the external parts of the retina), ciliary body and the iris
Central retinal artery - supplies the inner parts of teh retina directly

Front 93

Where do the opthalmic veins drain?

Back 93

Into the cavernous sinus

Front 94

What fibres mostly innervate the sphincter pupillae?

Back 94

Parasympathetic (resting -> don't need a big, open pupil)

Front 95

What fibres mostly innervate the dilator pupillae?

Back 95

Sympathetic (fight/flight -> need big wide open pupils)

Front 96

What happens when the ciliaris muscle contracts?

Back 96

It contracts DOWN --> fattens the lens = good for short distance site

Front 97

For short distance sight, what do we want the lens and ciliaris muscle to be doing?

Back 97

Short distance -> want fat lens. This is achieved by contraction of the ciliaris muscle (it contracts DOWN)

Front 98

For long distance eye sight, what do we want the lens and ciliaris muscle to do?

Back 98

Long distance -> want narrow, tight lens
This is achieved by relaxation of the muscle - it relaxes UP