Week 5 Flashcards
What does the occipitofrontalis consist of?
Paired frontal and occipital bellies separated by a single fibrous sheet.
What is the name of the sheet that separates the paired frontal and occipital bellies of the occipitofrontalis?
Epicranial aponeurosis
Where is the corregator spercilii in relation to the frontalis and orbicularis oculi?
Deep
What muscles are responsible for frowning?
- Corregator supercilii
- Occipitofrontalis
- Orbicularis oculi
Where is the orbicularis oculi in relation to the eyes?
It circles the eyes
What is the orbicularis oculi responsible for functionally?
- Closes eye
2. Directs tear flow
What can occur if the orbicularis oculi is paralysed?
- Prevents eye closure - dry cornea
- Lower eyelids falls down
- Tears run out and dirt comes in
What is the muscle that is responsible for lifting the upper eyelid?
Levator palpebrae sperioris
What are the muscles of the nose? (3)
- Procerus
- Nasalis
- Levator labii superioris alaquae nasae
What is the modiolis? Where does it extend?
- Fibromuscular structure
2. Extends from skin to mucosa
What is the function of the modiolis?
It is an anchoring point for muscles which move corners of mouth and adjacent structures.
What are the 7 muscles that insert into the modiolis?
- Zygomaticus major
- Levator anguli oris
- Buccinator
- Platysma
- Depressor anguli oris
- Orbicularis oris
- Risorius
What is the function of the zygomaticus major and levator anguli oris?
Elevates corner of the mouth
Where is the levator anguli oris located in relation to the facial vein and z. minor?
Deep
Where is the buccinator located?
It arises on the outer surfaces of the maxilla and mandible (over molars) and pterygomandibular raphe to attach to modiolis.
What is the function of the buccinator?
Draw in/position cheeks, direct food over molars
Where is the platysma located?
Body of mandible, modiolis and modiolar muscles to skin over pectoralis
What is the function of the platysma?
Has little function but can depress lower lip and corners of the mouth
What is the function of the depressor anguli oris?
Draws the corners of the mouth down
Where is the orbicularis oris located? What converges on it?
- Sphincter of mouth, modiolis to modiolis
2. Other muscles e.g. buccinator converge on it
The orbicularis oris has no direct bony attachments. True or False?
True.
Where are some of the fibres of the orbicularis oris derived from?
Buccinator
What happens when the orbicularis oris is paralysed?
- Can’t close mouth
2. Lips pulled toward normal side
What is the function of the risorius?
Moves corner of the mouth
What are the muscles responsible for moving the lip up?
- Levator labii superioris
- Levator labii superoris alaque nasi
- Zygomaticus minor
Where is the levator labii superioris located? What is its specific function?
- Deep
2. Raises upper lip
What is the specific function of the levator labii superoris alaque nasi?
- Raises upper lip
2. Dilates nostrils
What is the specific function of the zygomaticus minor?
Raises upper lip
What muscles are responsible for pulling the lip down?
- Depressor labii inferioris
2. Mentalis
Where is the depressor labii inferioris located? What is its specific function?
- Situated medial to depressor anguli oris
2. Moves lower lip down
What is the function of the mentalis?
Raises base of lower lip - protrusion and eversion
How do we identify the levator labii superioris alaque nasi?
By the 2 heads - one to nostril and one into upper lip. They arise beneath the orbicularis oris.
How do we identify the levator labii superioris?
Deep and lateral to levator labii superioris alaque nasi. The two muscles converge inferiorly.
How do we identify the levator anguli oris?
Very deep, lateral to levator labii superioris, deep to zygomaticus minor.
How do we differentiate the position of the z. major with z. minor?
- Z. major is lager and more later than Z. minor.
- Both blend with orbicularis oris BUT Z. major goes to the corner of the mouth, whereas, Z. minor goes to upper lip lateral to levator labii superioris and levator labii superioris alaque nasi.
Where does the mentalis muscles arise and how are the fibres oriented?
- Mentalis arises at the tip of the chin
2. The fibres fans laterally and upwards
Where does the depressor labii inferioris arise and how are the fibres oriented?
Arises laterally and converges medially and upward to blend with the orbicularis oris
How can we identify the buccinator?
Identify by parotid duct which pierces muscle before passing into vestibule of oral cavity.
What is the pterygomandibular raphe attached to?
Mandible and maxilla