Muscles of the head Flashcards
What do muscles of facial expression originate from?
Bone or fascia
What do muscles of facial expression insert into?
Skin
Where are muscles of facial expression located in terms of the tissue surrounding them?
In the subcutaneous tissue
How do muscles of facial expression exert their effects?
By pulling on the skin
What are the groups of muscles of the head?
Muscles of facial expression
Muscles of mastication
What are the muscles of facial expression?
Occipitofrontalis
Orbicularis oculi
Oribicularis oris
Buccinator
Zygomaticus, risorius
(platysma, even though it is in the neck)
What is the structure of occipitofrontalis?
Two bellies
- occipital
- frontal
Where is the frontal belly of occipitofrontalis located?
Above the eyebrows on the forehead
Where is the occpital belly of occipitofrontalis located?
Back of head over occipital bone
What innervates the frontal belly of occipitofrontalis?
Facial nerve - termporal branch
What innervates the occipital belly of occipitofrontalis?
Facial nerve - posterior auricular branch
What is the action of occipitofrontalis?
Elevates eyebrows
Wrinkles skin of forehead
How is occipitofrontalis examined?
Hold patient’s eyebrows down
ask them to raise there eyebrows against resistance
What is the structure of orbicularis oculi?
Two parts
- orbital part
- palpebral part
Where is the palpebral part of orbicularis oculi located?
Immediately around the eye
Where is the orbital part of orbicularis oculi located?
Around the palpebral part
What innervates orbicularis oculi?
Facial nerve - temporal and zygomatic branches
What is the action of the palpebral part of orbicularis oculi?
Close the eyes gently e.g. when blinking, sleeping
What is the action of the orbital part of orbicularis oculi?
Close the eyes tightly
How is orbicularis oculi examined?
Hold patient’s eyes open
Ask them to close their eyes against that resistance
Where is orbicularis oris located?
Around the opening of the mouth
What innervates orbicularis oris?
Facial nerve - buccal branch
What is the action of the oribularis oris?
Closes the mouth
Puckers the lips
How is orbicularis oris examined?
Inspect the mouth for drooping angle
if drooping, means the muscle isn’t working
Where is buccinator located?
Deep cheek
What is the innervation of buccinator?
Facial nerve - buccal branch
What is the action of buccinator?
Flattens cheek, holding cheek close to teeth
so food doesn’t pool between them
How is buccinator examined?
Ask patient to blow out cheeks
then apply pressure to them
Cheeks should resist expulsion of air
Where are zygomaticus and risorius located?
Superficial cheek
What is the innervation of zygomaticus and risorius?
Facial nerve - buccal branch
What is the action of zygomaticus and risorius?
Dilate the lips e.g. when smiling, frowning
How many muscles of mastication are there?
4
What are the muscles of mastication?
Temporalis
Masseter
Pterygoids - medial, lateral
Where is temporalis located?
On the side of the head, over the temporal bone
What innervates temporalis?
Trigeminal nerve - mandibular branch
What is the action of temporalis?
Elevates mandible
Retracts mandible
How is temporalis examined?
Ask patient to clench their jaw
palpate the side of their head
should be tense
Where is masseter located?
Above the back of the jaw
What innervates masseter?
Trigeminal nerve - mandibular branch
What is the action of masseter?
Elevates mandible
How is masseter examined?
Ask patient to clench their jaw
palpate above the back of their jaw
should be tense
Where are the medial and lateral pterygoids located?
Very deep in the cheek
What is the action of the medial pterygoid?
Elevates mandible
Assists lateral pterygoid in moving jaw to one side
What is the action of the lateral pterygoid?
Unilateral contraction - moves jaw to that side
Bilateral contraction - depress mandible
protract mandible
How are the pterygoids examined?
Hold patients mouth closed
ask them to open their mouth against the resistance
Ask them to move their jaw from side to side
What innervates the medial and lateral pterygoids?
Trigeminal nerve - mandibular branch
What joint do the muscles of mastication move?
Tempero-mandibular joint
What is special about the temporo-mandibular joint?
Only movable joint in the skull
