Muscles of the eyelids and adjacent face

Question 1

What are 4 key muscles of facial expression around the eye and eyelids?

Answer 1

1. Orbicularis oculi
2. Levator palpebrae superioris
3. Corrugator supercilii
4. Occipitofrontalis

Question 2

What is the function of orbicularis oculi in relation to the eye?

Answer 2

lid closure

Question 3

What is the function of levator palpebrae superioris in relation to the eye?

Answer 3

it raises the eyelid

Question 4

What is the overall shape of the orbicularis oculi muscle?

Answer 4

broad, flat sheet of skeletal muscle with orbital, palpebral and lacrimal portions

Question 5

What are the 3 portions of the orbicularis oculi split into?

Answer 5

1. orbital
2. palpebral
3. lacrimal

Question 6

What is the orientation of muscle fibres in orbicularis oculi and what does this reflect?

Answer 6

circular orientation - sphincter-like function of muscle

Question 7

From where does the orbital portion of the orbicularis oculi arise?

Answer 7

from the medial palpebral ligament and adjacent orbital margin

Question 8

What is the orientation of fibres in the orbital portion of orbicularis oculi?

Answer 8

the fibres run circumferentially in an elliptical fashion around and beyond the orbital margin

most pass arounf the lateral orbital margin without interruption, but some (depressor supercilii) are inserted into the skin and connective tissue of the eyebrow

Question 9

What are the depressor supercilii?

Answer 9

some fibres of the orbital portion of the orbicularis muscle, which are inserted into the skin and connective tissue of the eyebrow

Question 10

Where is the insertion of the depressor supercilli of the orbicularis oculi (orbital portion)?

Answer 10

skin and connective tissue of the eyebrow

Question 11

What is the palpebral portion of the orbicularis oculi muscle?

Answer 11

extremely thin muscle that originates from the medial palpebral ligament

Question 12

Where does the palpebral portion of the orbicularis oculi muscle arise from?

Answer 12

medial palpebral ligament

Question 13

What is the arrangement of muscle fibres in the palpebral portion of the orbicularis oculi?

Answer 13

fibres pass laterally within the eyelid anterior to the orbital septum and tarsal plate, and interlace to form the lateral palpebral raphe

Question 14

Where is the lacrimal portion of the orbicularis oculi located?

Answer 14

passes deep to the medial palpebral ligament, is attached to posterior lacrimal crest (behind lacrimal sac) as two muscle slips (upper and lower)

Question 15

where are the muscle fibre from the lacrimal part of orbicularis oculi inserted?

Answer 15

laterally into the tarsi close to the lacrimal canaliculi

Question 16

What is the function of the lacrimal portion of orbicularis oculi?

Answer 16

help draw the eyelids and lacrimal papillae medially and in addition dilate the lacrimal sac during blinking

helps suck tears into lacrimal punctum from lacus lacrimalis

Question 17

Identify the orabital and palpebral portions of orbicularis oculi on the image.

Question 18

What is the nerve supply of orbicularis oculi?

Answer 18

temporal and zygomatic branches of facial nerve, CNVII

Question 19

What is the action of the orbital portion of orbicularis oculi?

Answer 19

acts like purse string due to elliptical form and medial attachments: draws skin of forehead, temple, check and orbital margin towards the medial angle of the orbit, firmly closing the lids (e.g. in very bright light)

Question 20

What is the action of the palpebral portion of orbicularis oculi?

Answer 20

can act under both voulntary and involuntary control to close the eyelids during normal blinking (and sleeping)

Question 21

Why is the blink reflex important?

Answer 21

essential to integrity of ocular tear film and function of the cornea

Question 22

What is the corrugator supercilii and where is it located?

Answer 22

small pyramidal muscle at medial aspect of eyebrow, beneath occipitofrontalis and orbicularis oculi

Question 23

What is the action of the corrugator supercilii?

Answer 23

draws the eyebrow downwards and medially (frowning), producing vertical skin furrows on the forehead

Question 24

What does the corrugator supercilii protect the eyes from?

Answer 24

assists in protecting eyes in bright light

Question 25

What is the nerve supply to the corrugator supercilii?

Answer 25

small subdivisions of the temporal branch of the facial nerve

Question 26

Which msucle acts to produce vertical skin furrows in the forehead?

Answer 26

corrugator supercilii

Question 27

What is the structure of the occipitofrontalis?

Answer 27

fibromuscular layer which covers the dome of the skull from the eyebrows to the nuchal lines consists of two occipital bellies posteriorly attached via a thick fibrous layer, the galea aponeurotica, to the two frontal bellies

Question 28

What is the galea aponeurotica?

Answer 28

thick fibrous layer which connects the two occipital bellies of the occipitofrontalis to the two frontal bellies

Question 29

How does the frontal part of the occipitofrontalis relate to the orbital region?

Answer 29

* fibres form a thin quadrangular sheet that is attached to the superficial fascia above the eyebrows

Question 30

How are the a) medial b) intermediate c) lateral fibres of occipitofrontalis (frontal part) continuous with other facial muscles?

Answer 30

* a) medial = continuous with **procerus** * b) intermediate = **corrugator** **supercilii** and **orbicularis** **oculi** * c) lateral = **orbicularis** **oculi**

Question 31

What is the nervous supply to the frontal belly of occipitofrontalis?

Answer 31

temporal branches of facial nerve

Question 32

What is the action of contraction of the occipitofrontalis?

Answer 32

draws scalp backwards and elevates eyebrows, causing transverse wrinkles of scalp as in expressions of surprise, horror, fright, or glancing upwards

Question 33

Which muscle produces horizontal forehead wrinkles?

Answer 33

occipitofrontalis

Question 34

What is the action of levator palpebrae superioris?

Answer 34

opens eyelids; on relaxation, allows lid closure due to gravity

Question 35

What is the location of levator palpebrae superioris?

Answer 35

within orbit

Question 36

What is the origin of the levator palpebrae superioris?

Answer 36

lesser wing of sphenoid, above and in front of optic foramen, bleding with origin of superior rectus

Question 37

Which muscle does the origin of levator palpebrae superioris blend with?

Answer 37

superior rectus

Question 38

Where does the levator palpebrae superioris extend from, from its origin?

Answer 38

* muscle belly passes horizontally forward above the superior rectus, close to the orbital roof * behind the orbital margin it curves downwards into the lid where it becomes aponeurotic

Question 39

What is the organisation of the aponeurosis of levator palepbrae superioris?

Answer 39

the aponeurosis fans out on either side to form medial and lateral horns, which extend the whole width of the eyelid

Question 40

What is the insertion of levator palpebrae superioris?

Answer 40

inserts into skin of upper lid (causing horizontal palepbral sulcus or furrow) and anterior surface of the tarsal plate

Question 41

What is formed by the lateral horn of the LPS aponeurosis?

Answer 41

lateral palpebral ligament

Question 42

What is the insertion of the lateral palpebral ligament (formed by lateral horn of LPS aponeurosis)?

Answer 42

inserts into the lateral orbital tubercle

Question 43

What does the medial horn of the aponeurosis of LPS become?

Answer 43

medial palpebral ligament

Question 44

What is the site of insertion of the medial palpebral ligament?

Answer 44

frontolacrimal suture

Question 45

What is the nerve supply to the levator palpebrae superioris?

Answer 45

superior division of the oculomotor nerve

Question 46

What is the action of the LPS on contraction?

Answer 46

elevates the upper lid, thereby opening the palpebral fissure

Question 47

What can be found on the inferior aspect of the levator palpebrae superioris?

Answer 47

superior tarsal or Müller's muscle

Question 48

What is the attachment of the superior tarsal / Müller's muscle?

Answer 48

attached anteriorly to the upper surface of the tarsal plate and cojunctival fornix

Question 49

What is the innervation to the superior tarsal/ Muller's muscle on the inferior aspect of LPS?

Answer 49

sympathetic innervation

Question 50

What is the action of contraction of the superior tarsal / Muller's muscle?

Answer 50

assists levator in elevating eyelid

Question 51

What is the closest equivalent to the superior tarsal in the lower eyelid?

Answer 51

small group of smooth muscle fibres (inferior tarsal muscle) that originate from the fascial sheath of inferior rectus and insert into the lower tarsus