The Temporomandibular Joint Flashcards
Name the muscles of mastication
- Temporalis
- Masseter
- Medial pterygoid
- Lateral pterygoid
What does the Temporalis do?
It elevates and retracts the mandible during chewing
What does the Masseter do?
Elevates the mandible but can also protrude
Where is the Temporalis?
Lies above your temporal bone and attaches to the condyle
Name the strongest of the 4 muscles of mastication
Masseter
What does the medial pterygoid muscle do?
Mainly elevates the mandible
How can we differentiate between the medial and lateral pterygoid
The medal pterygoid muscle runs in the same direction as the Masseter but is found deeper than the Masseter and is a little bit smaller
Where is the medial pterygoid muscle found?
Attaches to the medial surface of the lateral pterygoid plate
What is the lateral pterygoid plate part of?
The sphenoid bone
What is the lateral pterygoid muscle split into?
2 heads:
- Superior head
- Inferior head
What does the superior head of lateral pterygoid muscle do?
It pulls the capsule and disk forward during mouth opening to maintain the relationship between mandibular condyle and TMJ disk
It also stabilises the condyle during chewing
What does the inferior head fo the lateral pterygoid do?
It depresses the mandible
Needed in protrusion
Causes lateral movement of the mandible
Where does the lateral pterygoid muscle attach?
Attaches to the outer surface of the lateral pterygoid plate
name the foramen found in the sphenoid bone
- Foramen rotundum
- Foramen Ovale
- Foramen spinosum
Which nerve passes through the foramen rotundum?
The maxillary division of the trigeminal nerve (V2)
Which nerve passes through the foramen Ovale?
The mandibular division of the trigeminal nerve (V3)
What makes up the TMJ
- The condyle
- Temporal bone
- Disk
- Nerves
Where does the TMJ lie?
Just anterior to the ear canal
Describe the nerves found in the TMJ. What does this mean?
They are nociceptive nerves which means they detect pain
What is the structure of the TMJ describes as
A complex synovial joint
What does a synovial joint usually contain
Synovial fluid
What are the advantages of having synovial fluid?
Acts as a lubricant and provides cushioning
Where does the condyle of the mandible sit?
Sits in the mandibular fossa of the temporal bone
Where is the articular disk found?
Between the head of the mandible and the bone of the mandibular fossa
What is the aim of the articular eminence?
It prevents the condyle from popping out of the TMJ
Where is the articular eminence found?
It is a dip of bone found in the mandibular fossa
What is the TMJ separated into?
2 Distinct cavities:
Upper joint cavity
Lower joint cavity
What are the upper and lower cavities of the TMJ separated by?
Fibrocartilaginous articular disk
What does the head of the mandible need to do to be able to move your mouth?
Needs to rotate and translate
In which direction does the head of the mandible translate
Antero-posteriorly