extraocular muscles

Question 1

What are the 4 rectus muscles? & what are the two oblique muscles?

Answer 1

rectus
1. inferior
2. superior
3. lateral
4. medial
obliques
1. superior
2. inferior

Question 2

When the head tilts the eyes ____?

Answer 2

eyes move in the opposite direction to head movement

Question 3

What is the connective tissue ring that contains five of the extra ocular muscles origin?

Answer 3

annulus of Zinn
(SR, IR, MR ,LR SO
*all except the IO

Question 4

where do the extra ocular muscles insert?

Answer 4

tenon’s capsule

Question 5

What are the horizontal and vertical movers?

Answer 5

horizontal = lateral and medial rectus
vertical = superior and inferior rectus

Question 6

What is the 7th extraocular muscle?

Answer 6

levator palpebrae superioris
(inserts at our eyelids)

Question 7

the medial rectus inserts _____ to the _____?

Answer 7

closes to the limbus

Question 8

Line connecting the muscle insertions from a spiral called?

Answer 8

the spiral of tillaux
MILS from closest to furtherest of limbus
5 ,6 ,7 8 mm from limbus

Question 9

the four rectus muscles insert____?

Answer 9

anterior to the equator

Question 10

what are the functions of connective tissue pulleys?

Answer 10

1. maintain stability
2. reduce sideslip
3. determine effective direction of pull

Question 11

What is a function of check ligaments?

Answer 11

-To make sure the globe cant keep rotating
- anchor the MR and LR to the preorbita at the anterior orbital walls

Question 12

What is the isolated agonist model?

Answer 12

explains eye movements; during eye movements all six extraocular muscles are in some state of contraction or relaxation

Question 13

What is the largest of the extraocular muscles?

Answer 13

medial rectus

Question 14

What is the spina recti lateralis?

Answer 14

boney projection on the wall of the sphenoid bone

Question 15

What is the only extra ocular muscle that does NOT come from the annulus

Answer 15

inferior oblique

Question 16

what is the longest & thinnest of the extraocular muscles & what is its origin?

Answer 16

superior oblique
origin: lesser wing of the sphenoid bone, medial to the optic canal

Question 17

what is the trochlear?

Answer 17

a cartilaginous pulley

Question 18

what is the insertion of the inferior oblique?

Answer 18

inserts: posterior lateral aspect of the globe

Question 19

What nerves innervate which extraocular muscles?

Answer 19

medial recuts = CN III
lateral rectus = CN VI
superior rectus = CN III
inferior rectus = CN III
superior oblique = CN IV
inferior oblique = CN III

Question 20

What is the origin of the levator palbebrae superioris (LPS)?

Answer 20

lesser wing of the sphenoid above the annulus of Zinn

Question 21

What are the insertions of the levator palbebrae superioris (LPS)?

Answer 21

1. cutaneous skin
2. osseous (having to do with bone)
3. superior fornix
4. tarsal plate

Question 22

What is the levator aponeurosis?

Answer 22

As the LPS enters the eyelid it becomes a fan shaped tendon known as the levator aponeurosis

Question 23

What is the capsulopalpebral fascia? where does it insert?

Answer 23

the retractor of the lower lid (lower eyelid aponeurosis)
inserts into the inferior edge of the tarsal plate

Question 24

When there is enlargement of the extraocular muscles or adipose tissue which muscle is commonly involved?

Answer 24

inferior rectus

Question 25

how can we isolate the superior and inferior rectus as vertical movers

Answer 25

with the eye abducted 23 degrees from primary position

Question 26

how can the superior oblique and inferior oblique muscles be isolated and which of their movements will they make?

Answer 26

adduct 51 to 55 degrees
the muscles can only perform their secondary actions
SO: Depression
IO: Elevation

Question 27

When can NO vertical rectus movement occur? & When can NO oblique muscle movement occur?

Answer 27

rectus: adducted 67 degrees
obliques: 35-59 degrees

Question 28

How to determine mechanical vs neurological restriction?

Answer 28

perform Ductions (movement involving just one eye)
Neurological = improved range of motion
Mechanical = restriction remains the same

Question 29

The ciliary ____________ causing the zonules to _________to adjust the lens for distance vision

Answer 29

The ciliary relaxes causing the zonules to contract to adjust the lens for distance vision

Question 30

The ciliary ______ causing the zonules to _______ and allow the lens to focus up close (accomodation)

Answer 30

The ciliary body contracts causing the zonules to relax and allow the lens to focus up close

Question 31

EOM’s are _______ muscles?

Answer 31

skeletal muscles