Functions-Muscles of mastication Flashcards
Compare the difference between a muscle origin and insertion.
The muscle origin is the attachment site that doesn’t move when the muscle contracts.
The insertion is the attachment site that does move when the muscle contracts.
Give the following of the Temporalis muscle?
- Insertion
- Origin
- Action
Origin: Floor of the temporal fossa
Insertion: Coronoid process & anterior border of the ramus
Action: Elevates and retracts the mandible
Give the following of the Masseter muscle?
- Insertion
- Origin
- Action
Insertion- Lateral surface and angle of the mandible
Origin- Zygomatic arch
Action- Elevates the mandible
Give the following of the Lateral pterygoid muscle?
- Insertion
- Origin
- Action
Origin- Lateral surface of the lateral pterygoid plate
Insertion-
- Superior belly- anterior border of the condyle
- Inferior belly- intra-articular disc.
Action- Lateral movement of the jaw and jaw opening.
Give the following of the Medial pterygoid muscle?
- Insertion
- Origin
- Action
Origin-
- Deep head- medial surface of the lateral pterygoid
- Superficial head- tuberosity of maxilla
Insertion- medial surface of the angle of the mandible
Action- elevates and assists protrusion of the mandible
Compare the medial and lateral pterygoids.
the lateral pterygoid has 1 origin and 2 insertions
The medial pterygoid has 2 origins 1 insertion.
Compare the examination techniques for the mandibular muscles:
Temporalis- ask patient to clench and palpate above the ear.
Masseter- Place one finger intra-orally and one on the cheek.
Lateral pterygoid- record response to movement (checking if the muscle resists movement)
Following an IV the patient is unable to open their mouth the next day. What has happened?
The patient is suffering from trismus.
This is because the medial pterygoid has accidentally been hit by the injection.
We know this as it is the deepest muscle (so the first you would come in contact with intra-orally)
Describe the two movements of the TMJ
TMJ rotation this is the initial opening and is a hinge movement.
TMJ translation- This is a sliding movement where the Condyle can move
- forward along the articular eminence (opening the mouth)
- back into the fossa (which closes the mouth)
Describe the factors that affect biting force:
- Physchology- We do not bite as hard as we can as we do not want to damage our teeth.
- Muscle mass- A patient with larger muscles will have a larger biting force.
- Muscle fibre type- Type II muscle fibres (fast twitch) generate a larger biting force.
- Tooth type and position - the greatest force is generated by the 1st molars as they are nearer the force generating muscles.
How are the infrahyoid and suprahyoid muscles used in mastication?
These stabilise the hyoid bone during chewing.
Which muscles are these?
Label them and state their function.
Suprahyoid muscles
Function- elevation of the hyoid bone
- Digastric
- Geniohyoid
- Mylohyoid
- Stylohyoid
5.
Which muscles are these?
Label them and state their function
Infrahyoid strap muscles
Function- depression of the hyoid bone
- Thyrohyoid (
- Sternothryoid (sternum to thyroid)
- Omohyoid
- Sternohyoid (sternum to hyoid)
Describe the muscles of the tounge
There are two types of muscles found in the tounge:
The Intrinsic- alter the tounge shape
Longitudinal/ vertical/ transverse
The extrinsic- alter tounge shape and position
Genioglossus / hyoglossus/styloglossus/ palatoglossus.
Label the intrinsic muscles of the tounge
A- longitudinal
B- vertical
C- transverse
Label the extrinsic muscles of the tounge
A- genioglossus
B- hyoglossus
C- palatoglossus
D- styloglossus
