Muscles of Facial Expression Flashcards
Where are the muscles of facial expression found (with regards to fascia)
Muscles of facial expression are found in the superficial fascia around facial orifices
Where do muscles of facial expression tend to originate?
Bone or fascia
Where do muscles of facial expression tend to insert?
Skin
Where do wrinkles form?
Wrinkles form at 90 degrees to the muscle fibre direction
What cranial nerve innervates the muscles of facial expression?
CN VII (facial nerve)
What are the 2 functions of muscle of facial expression
Dilators and Sphincters -
control the opening of facial orifices
Movers of overlying skin -
reflect various facial expressions
How are the muscles of facial expression grouped?
By regions
What are the 5 muscles of facial expression of the mouth?
1- Obicularis Oris 2-Levator Anguli Oris 3- Depressor Anguli Oris 4- Zygomaticus Major 5- Risorius
Obicularis Oris? (OPENS)
Sphincter encircling mouth.
Fibres originate mainly from contributions of other facial muscles, also from labial alveolar bone
Closes oral aperture, protrude lips, press lips against teeth
Levator Anguli Oris? (SMILE)
Originates at the canine fossa
Inserts at the angle of the mouth, blends with fibres of Obicularis Oris
Acts to lift the angle of the mouth
Depressor Anguli Oris? (SAD)
Triangular muscle
Base: originates from external oblique line of mandible
Apex: fibres ascend and converge to apex at angle of mouth, blend with fibres of obicularis oris
Acts to pull angle of mouth downwards
Zygomaticus Major (LAUGHING)
Arises: facial aspect of zygomatic bone
Inserts: fibres descend down and medially to the angle of the mouth, blend with fibres of obicularis oris
Acts to lift angle of mouth upward and backward
Risorius (GRINNING)
Thin, wispy but large
Arises: parotid fascia, small contribution from platysma fibres
Inserts: transversely into angle of mouth
Acts to retract angle of the mouth backwards
What are the 3 muscles of facial expression associated with the lips of the mouth?
Quadratus Superioris
Depressor Labii Inferioris
Depressor Anguli Oris
What 4 muscles compose the quadratus superioris?
1-Zygomaticus Major (as above)
2-Zygomaticus Minor - just medial to z major, lifts angle of mouth
3-Levator Labii Superioris -, medial to z minor, lifts UPPER lip
[[levator anguli oris - medial to LLS, lifts corner of mouth]]
4- Levator Labii Superioris Alaeque Nasi - lifts upper lip and alar cartilage of nose
Depressor Labii Inferioris?
Arises: lower portion of oblique line of mandible
Inserts: lower lip
Acts: depresses LOWER lip
Depressor Anguli Oris?
Most superficial of all lower oral muscles
Arises: chin
Inserts: modiolus (corner of mouth)
Acts: depresses angle of mouth
What is the muscle of facial expression which extends from the front of the head to the back of the head?
The occipitofrontalis: Starts at Occipital belly: arises - from superior nuchal line and mastoid process inserts - epicranial aponeurosis Ends with Frontal belly: arises - epicranial aponeurosis inserts - obicularis oculi
What is the acronym for SCALP?
Skin Connective tissue (highly vascularised) Aponeurosis Loose connective tissue Pericranium
What is the muscle of facial expression associated with the cheek?
Buccinator
Buccinator?
Origin: pterygomandibular raphé, alveolar processes of maxilla and mandible
Fibres sweep forward through cheek as flattened sheet
Insertion: Inferior fibres sweep upwards and superior fibres sweep downwards to blend with obicularis oris
Action:
Prevents cheeks from expanding when forcefully pushing out air (brass instruments)
AIDS in mastication (but still classed muscle of facial expression) as pushes cheeks against vestibular surfaces of molar teeth and so pushes food onto occlusal surfaces of teeth.
What is the muscle of facial expression associated with the chin?
Mentalis
Mentalis?
deep to depressor labii inferioris and depressor anguli oris.
Conical muscle
Origin: incisive fossa
Insertion: skin of chin
Acts: contraction puckers skin overlying chin which help obicularis oris to clear food from mandibular labial vestibule