Anatomy 1 - Orbit and the Eye

Question 1

What is an orbital blow out fracture?

Answer 1

A fracture of one or more of the bones of the floor of the orbit (usually caused by indirect trauma i.e. hit another part of the face causing the thinner part of the floor to fracture)

Question 2

What 3 bones form the orbital margin?

Answer 2

Frontal
Zygomatic
Maxillary

Question 3

What is an orbital plate?

Answer 3

Part of the bone that forms part of the orbit

Question 4

What 7 bones make up the orbit?

Answer 4

Frontal
Zygomatic
Maxillary
ethmoid
Lacrimal
Sphenoid
Palatine

Question 5

What bone does the optic canal pass through?

Answer 5

Sphenoid bone

Question 6

Name the 2 holes located on the floor of the orbit?

Answer 6

Superior and inferior orbital fissure

Question 7

What is the purpose of the eyelid?

Answer 7

To protect the eye

Question 8

What 4 structures of the eyelid help it protect the eye?

Answer 8

outer skin
inner conjuntiva
tarsal plate
Tarsal glands

Question 9

What do tarsal glands secrete?

Answer 9

Oily substance (special type of sebaceous gland)

Question 10

What is the purpose of the tarsal plate?

Answer 10

Helps maintain the shape of the eyelids

Question 11

What is the name of the membranous sheet that acts as the anterior boundary of the orbit?

Answer 11

Orbital septum

Question 12

Where does the orbital septum extend from?

Answer 12

The orbital rims to the eyelids

Question 13

What 2 muscles does the eyelids contain?

Answer 13

Obicularis oculi

Levator palpebrae superioris

Question 14

What muscle closes the eyelids?

Answer 14

Obicularis Oculi

Question 15

Innervation of obicularis oculi?

Answer 15

CN VII

Question 16

Which muscle raises the eyelids?

Answer 16

Levator palpebrae superioris

Question 17

What nerve innervates levator palpebrae superioris?

Answer 17

CN VIII

Question 18

What is the function of tears?

Answer 18

To keep the eyes moist
Flush out foreign bodies
Contains sugar and oxygen to supply the cornea

Question 19

What produces tears?

Answer 19

The lacrimal gland

Question 20

What is the nerve supply to the lacrimal gland?

Answer 20

CN VII

Question 21

Where do tears pass from the cornea?

Answer 21

The puncta lacrimalia (minute circular opening of the lacrimal canaliculus)

Question 22

Where do tears pass from the puncta lacrimalia?

Answer 22

Canuliculi

Question 23

Where do tears pass from the canuliculi?

Answer 23

Lacrimal sac

Question 24

Where does tears pass from the lacrimal sac?

Answer 24

To the nasolacrimal duct

Question 25

Where does the nasolacrimal duct drain?

Answer 25

Into the inferior meatus on the lateral wall of the nasal cavity

Question 26

What is the name of the act of the altering the shape and curvature of the lens to adjust the degree of refraction?

Answer 26

Accommodation

Question 27

Describe the process of accommodation when focussing on a near object?

Answer 27

the ciliary muscle contract causing the suspensory ligaments to slacken = muscle tension on the lens is low and the lens shape is fat and more curved

Question 28

Describe the process of accommodation when focussing on a distant object?

Answer 28

the ciliary muscles relax causing the suspensory ligaments to be stretched = muscle tension on the lens is high = thin, less curved lens

Question 29

What type of muscle is the ciliary muscle?

Answer 29

Smooth muscle

Question 30

Nerve supply to the sphincter pupillae?

Answer 30

CN III

Question 31

What are the 2 smooth muscles located within the iris?

Answer 31

Sphincter pupillae | Dilator pupillae

Question 32

What type of autonomic control is sphincter pupillae under?

Answer 32

Parasympathetic (CN III)

Question 33

What type of autonomic control is dilator pupillae under?

Answer 33

Sympathetic

Question 34

When does sphincter pupillae contract?

Answer 34

In bright light, accommodation

Question 35

When does dilator papillae contract?

Answer 35

Dim light, fright

Question 36

Name of part of the eye in front of the lens? | What does this contain

Answer 36

Anterior segment | Aqueous humour

Question 37

Name of the part of the eye behind the lens? | What does this contain

Answer 37

Posterior segment | Vitreous humour

Question 38

What 2 parts can the anterior segment be broken down to?

Answer 38

``` Anterior chamber (between cornea and iris) Posterior chamber (between iris and suspensory ligaments) ```

Question 39

Name of the 6 extrinsic muscles of the eye?

Answer 39

``` Superior oblique Inferior oblique Superior rectus Inferior rectus Lateral Rectus Medial rectus ```

Question 40

Where do all the rectus muscles originate from?

Answer 40

Common tendinous ring

Question 41

Where do all the extra ocular muscles insert onto?

Answer 41

Sclera

Question 42

Action of superior rectus?

Answer 42

Elevates the eye

Question 43

Action of inferior rectus?

Answer 43

Depresses the eye

Question 44

Action of lateral rectus?

Answer 44

Abducts the eye

Question 45

Action of medial rectus?

Answer 45

Adducts the eye

Question 46

Action of superior oblique muscle?

Answer 46

Down and out (tramp muscle)

Question 47

Action of inferior oblique muscle?

Answer 47

Up and out

Question 48

What is the general principle of testing the eye muscles?

Answer 48

Want to test the movement of individual muscles = have to line up gaze to plane of muscles being tested = isolates muscle movement

Question 49

How to test that action of lateral rectus muscle?

Answer 49

Get the abduct their eye

Question 50

How to test the action of the medial rectus?

Answer 50

Get the patient to adduct their eye

Question 51

How to test the action of superior rectus?

Answer 51

Get the patient to look out and up

Question 52

How to test the action of the inferior rectus?

Answer 52

Get the patient to look out and down

Question 53

How to test the action of the inferior oblique?

Answer 53

Get the patient to look in and up

Question 54

How to test the action of the superior oblique?

Answer 54

Get the patient to look in and down

Question 55

Name of the depression in the frontal bone on the medial part of the optic ridge?

Answer 55

Supraorbital notch/ foramen

Question 56

Name of the foraminae in the maxillary bone just below the orbital margin?

Answer 56

Infraorbital foramen

Question 57

What is another name for the base of the orbit?

Answer 57

Orbital rim

Question 58

What is the orbital rim made from?

Answer 58

The superior, inferior, medial and lateral orbital margins

Question 59

What 2 parts of the orbit are especially thin?

Answer 59

The medial wall and orbital floor

Question 60

What is the name of the 2 parts of obicularis oculi?

Answer 60

Orbital and palpebral parts

Question 61

Name of the ligaments at either corners of the eyes?

Answer 61

Lateral and medial palpebral ligaments

Question 62

Name of the tendons that immediately surround the eyes?

Answer 62

Superior tarus | Inferior tarus

Question 63

Name of the tendon extending superiorly from the superior tarus?

Answer 63

Tendon of levator palpebrae superiorus

Question 64

What is another name for the corneoscleral junction?

Answer 64

the limbus

Question 65

What happens to aqueous secreted by the ciliary processes?

Answer 65

It circulates within ht posterior chamber nourishing the lens before passing through the pupil into the anterior chamber where it nourishes the cornea Aqueous is then reabsorbed

Question 66

Where is aqueous reabsorbed?

Answer 66

Into scleral venous sinus at the iridocorneal angle

Question 67

What is the fundus?

Answer 67

The posterior area of the eye where light is focused