Muscles of Facial Expression

Question 1

What are the layers of the scalp ?

Answer 1

SCALP
Skin

Connective tissue - dense, vascular superficial fascia

Aponeurosis - epicranial/Galen aponeurosis

Loose connective tissue

Pericranium - periosteum of cranium

The superficial 3 layers are tightly attached to each other so scalping injuries usually involve cleaving of the plane of the Loose connective tissue

Question 2

Describe risk of infection in relation to scalp:

Answer 2

Infection spreads easily in the LCT layer & is dangerous because of connections with emissary veins that drain to veins inside the skull

Question 3

Describe some general characteristics of Muscles of Facial expression:

Answer 3

Superficial muscles - most attach skin to bone/ fascia thereby changing facial expression
Innervated by facial nerve - cranial nerve VII

Question 4

Describe the occipitofrontalis:

Answer 4

Occipital belly which attaches to occipital bone
Frontal belly which attaches to frontal bone
2 bellies separated by epicranial aponeurosis

Function - raises eyebrows

Question 5

Describe the nasalis:

Answer 5

Maxilla near medial orbit
Alar cartilage of nose
Function - flares nostrils

Question 6

Describe the Orbicularis oculi:

Answer 6

Attach medially to Medial orbit
Runs around the skin around orbit & eyelids
Function;
- Outer ring closes eye forcefully
- Inner ring closes gently

Question 7

Describe the procerus

Answer 7

Function - Transverse wrinkle between eyes
Origin - nasal cartilage
Insertion - skin between the eyebrows

Question 8

Describe the Orbicularis oris

Answer 8

Medial maxilla & mandible, modiolus (angle of mouth)
Skin of lips
Function - close and protrude lips

Question 9

Describe the Zygomaticus minor & major

Answer 9

Major is superior to minor
Origin - zygomatic arch
Insertion - skin of upper lip
Function - Elevate, retract upper lip, help smiling

Question 10

Describe the Levator anguli oris:

Answer 10

Origin - Maxilla near canines
Insertion - Modiolus
Function - elevate angle and help smiling function

Question 11

Describe the Levator labii superioris:

Answer 11

Origin - Maxilla near inferior orbit
Insertion - Skin of upper lip
Function - Elevate, retract upper lip, pulls corner of lip up “The rock”

Question 12

Describe the buccinator:

Answer 12

Origin - Mandible, Maxilla, pterygomandibular raphe
Insertion - Modiolus
Function - Presses cheek against teeth, resists distension, “sphincter” of parotid duct

Question 13

Describe the depressor anguli oris:

Answer 13

Origin - Mandible
Insertion - Modiolus
Function - Depress inferior lips
Lateral to DLI and superior to Platysma

Question 14

Describe the Depressor labii inferioris:

Answer 14

Origin - Mandible
Insertion - Skin of lower lip
Function - Depress, retract lower lip

Question 15

Describe the mentalis

Answer 15

Origin - Mandible near incisors
Insertion - Skin of chin
Function - Elevate, protrude lower lip

Question 16

Describe the platysma:

Answer 16

Origin - Supraclavicular skin
Insertion - Mandible, skin of lower lip
Function - Depress mandible, tense skin of neck
Most inferior of facial muscles

Question 17

Describe the facial nerve:

Answer 17

Runs from Internal acoustic meatus to Facial canal top Stylomastoid foramen

Enters the Parotid salivary gland & divides into 5 terminal branches;
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical

Question 18

What is Bell’s palsy ?

Answer 18

Cause - idiopathic (unknown)
Symptom;
- facial muscle paralysis
- ptosis (drooping eyelid)
- dry mouth
- Hyperacusis (noise sensitivity)
Treatment - anti inflammatory steroids

Question 19

What is botox ?

Answer 19

Blocks acetylcholine release at neuromuscular junction which inhibits muscular contraction

Question 20

Describe the parotid gland:

Answer 20

Extend from the lower edge of the zygomatic arch to the angle of the mandible
Saliva from parotid gland runs in parotid duct to the mouth
Parasympathetic innervation by glossopharyngeal nerve