Muscles of facial expression - orbital group

Question 1

where are muscles of facial expression located?

Answer 1

in subcutaneous tissue

Question 2

where do muscles of facial expression originate from? insert?

Answer 2

bone or fascia and insert onto the skin

Question 3

by contracting, how do the muscles exert their effects?

Answer 3

by pulling on the skin

only group of muscle that inserts into the skin

Question 4

what is the common embryonic origin of this group of muscles?

Answer 4

2nd pharyngeal arch

Question 5

how do nerves innervate this group of muscles? (embryology)

Answer 5

as the muscles migrate from the 2nd pharyngeal arch, they take the nerve supply with them

Question 6

what are all the muscles of the facial expression innervated by?

Answer 6

facial nerve (CN VII)

Question 7

how can the facial muscles be split?

Answer 7

roughly into 3 groups:
orbital
nasal
oral

Question 8

what does the orbital group of facial muscles contain?

Answer 8

2 muscles associated with the eye socket

Question 9

what does the orbital group of facial muscle control?

Answer 9

the movements of the eyelids
important in protecting cornea from damage
innervated by facial nerve (CN VII)

Question 10

what are the muscles of the orbital group?

Answer 10

orbicularis oculi

corrugator supercilli

Question 11

where is the orbicularis oculi located?

Answer 11

muscle surrounds the eye socket and extends into the eyelid

Question 12

what is the function of orbicularis oculi?

Answer 12

functionally split into 2 parts:
outer orbital part
inner palpebral part

Question 13

what is the action of palpebral part of orbicularis oculi?

Answer 13

performs gentle closure of the eyelid

gentle palpate

Question 14

what is the action of the orbital part of the orbicularis oculi?

Answer 14

closes eyelid fOrcefully

Question 15

where is the corrugator supercilli muscle located?

Answer 15

much smaller muscle, located posteriorly to the orbicularis oculi muscle

Question 16

where does the corrugator supercilli muscle originate and insert?

Answer 16

originates from superciliary arch, runs in superolateral direction
inserts into skin of eyebrown

Question 17

what is the action of the corrugator supercilli muscle?

Answer 17

acts to draw eyebrows together, creating vertical wrinkles on the bridge of the nose

Question 18

what is the innervation of corrugator supercilli?

Answer 18

facial nerve (CN VII)

Question 19

Clinical: what happens if facial nerve becomes damaged? (in terms of orbital muscles)

Answer 19

orbital muscles will cease to function

Question 20

Clinical: what happens if orbital muscles cease to function?

Answer 20

the eye cannot shut

the lower eyelid droops

Question 21

clinical: what happens if the eye cannot shut?

Answer 21

can cause the cornea to dry out

Question 22

what is it called when the cornea dries out?

Answer 22

exposure keratitis

result of facial nerve damage

Question 23

what happens if the lower eyelid droops as a result of facial nerve damage?

Answer 23

lacrimal fluid pools in the lower eyelid, and cannot be spread across the surface of the eye

Question 24

what can happen if the lacrimal fluid pools in the lower eyelid and cannot spread across the surface of the eye?

Answer 24

result in a failure to remove debris and ulceration of the corneal surface

Question 25

what is it called when the lower eyelid droops?

Answer 25

ectropion

Question 26

what is the test for facial nerve palsy?

Answer 26

raising the eyebrows and closing the eyelids