Muscles of Facial Expression Flashcards
What are the layers of the scalp ?
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
Describe risk of infection in relation to scalp:
Infection spreads easily in the LCT layer & is dangerous because of connections with emissary veins that drain to veins inside the skull
Describe some general characteristics of Muscles of Facial expression:
Superficial muscles - most attach skin to bone/ fascia thereby changing facial expression
Innervated by facial nerve - cranial nerve VII
Describe the occipitofrontalis:
Occipital belly which attaches to occipital bone
Frontal belly which attaches to frontal bone
2 bellies separated by epicranial aponeurosis
Function - raises eyebrows
Describe the nasalis:
Maxilla near medial orbit
Alar cartilage of nose
Function - flares nostrils
Describe the Orbicularis oculi:
Attach medially to Medial orbit
Runs around the skin around orbit & eyelids
Function;
- Outer ring closes eye forcefully
- Inner ring closes gently
Describe the procerus
Function - Transverse wrinkle between eyes
Origin - nasal cartilage
Insertion - skin between the eyebrows
Describe the Orbicularis oris
Medial maxilla & mandible, modiolus (angle of mouth)
Skin of lips
Function - close and protrude lips
Describe the Zygomaticus minor & major
Major is superior to minor
Origin - zygomatic arch
Insertion - skin of upper lip
Function - Elevate, retract upper lip, help smiling
Describe the Levator anguli oris:
Origin - Maxilla near canines
Insertion - Modiolus
Function - elevate angle and help smiling function
Describe the Levator labii superioris:
Origin - Maxilla near inferior orbit
Insertion - Skin of upper lip
Function - Elevate, retract upper lip, pulls corner of lip up “The rock”
Describe the buccinator:
Origin - Mandible, Maxilla, pterygomandibular raphe
Insertion - Modiolus
Function - Presses cheek against teeth, resists distension, “sphincter” of parotid duct
Describe the depressor anguli oris:
Origin - Mandible
Insertion - Modiolus
Function - Depress inferior lips
Lateral to DLI and superior to Platysma
Describe the Depressor labii inferioris:
Origin - Mandible
Insertion - Skin of lower lip
Function - Depress, retract lower lip
Describe the mentalis
Origin - Mandible near incisors
Insertion - Skin of chin
Function - Elevate, protrude lower lip
Describe the platysma:
Origin - Supraclavicular skin
Insertion - Mandible, skin of lower lip
Function - Depress mandible, tense skin of neck
Most inferior of facial muscles
Describe the facial nerve:
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
What is Bell’s palsy ?
Cause - idiopathic (unknown)
Symptom;
- facial muscle paralysis
- ptosis (drooping eyelid)
- dry mouth
- Hyperacusis (noise sensitivity)
Treatment - anti inflammatory steroids
What is botox ?
Blocks acetylcholine release at neuromuscular junction which inhibits muscular contraction
Describe the parotid gland:
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
