W2: S5 - The Mandible, Teeth and TMJ Flashcards
- Coronoid process
- Alveolar process
- Mental protuberance
- Mental foramen (inf. alveolar nerve)
- Angle
- Body
- Ramus
- Mandibular notch
- Head (condyle)
What are the anatomical changes of the edentulous mandible??
- Lack of mandibular height
- No teeth
- Posterior mandible wider
What are the names of adult and baby teeth?
Baby teeth = deciduous
Adult teeth = permanent
How many baby teeth do we have?
Incisors = 8
Canines = 4
Molars = 8
How many permanent teeth do we have?
Incisor = 8
Canines = 4
Premolars = 8
Molars = 12
What type of joint is the temperomandibular joint (TMJ)?
Synovial hinge
What are the 2 articular processes of the TMJ?
Condyle of mandible
Mandibular fossa of temporal bone
What are the 5 movements that occur at the TMJ?
Elevation
Depression
Protrusion
Retraction
Side to side movements
What nerve innervates the sensation of the TMJ?
V3
What is the definition of “muscles of mastication”?
Muscles that act on the TMJ during chewing
What are the 4 muscles of mastication?
- Temporalis
- Masseter
- Lateral pterygoid
- Medial pterygoid
What are the bony attachements of the temporalis?
Origin = fossa termporalis
Insertion = coronoid process
Note: the posterior fibres of the temporalis are almost horizontal and the anterior ones are almost vertical i.e. this allows a wide range of movement
What action do the anterior fibres of the temporalis have on the mandible?
Elevation
What are the bony attachments of the masseter? And it’s actions?
Origin = zygomatic bone + arch
Insertion = outer surface of the ramus and the angle
Actions = elevation and protrusion
What bone in the skull floor do the pterygoid muscles attach?
Sphenoid bone
What part of the sphenoid bone do the pterygoid muscles attach?
Lateral pterygoid plate
Identify the lateral pterygoid plate
13
What part of the pterygoid plate does the lateral pterygoid attach to?
Lateral part
What part of the pterygoid plate does the medial pterygoid attach to?
Medial part
Where does the lateral pterygoid attach to on the mandible?
- Enters the TMJ joint capsule
- Attaches to the neck of the mandible
What part of the mandible does the medial pterygoid attach to?
Medial surface of angle and ramus
How does the mandible move when both lateral pterygoids contract?
Protraction
How does the mandible move when the medial and lateral pterygoid on one side contract?
Side to side movements
How does the mandible move when both medial pterygoid muscles contract?
Elevation
Which of the suprahyoid muscles depress the mandible?
- Mylohyoid
- Anterior digastric
- Geniohyoid
What muscles elevate the mandible?
- Masseter
- Temporalis
- Medial pterygoid
What muscles cause protrusion of the mandible?
Masseter
What muscles cause retraction of the mandible?
Lateral pterygoid
What muscles cause side to side movement of the mandible?
Both pterygoids contracting at once
What structure do the motor fibres of the mandibular division of the trigeminal nerve enter to supply the muscles of mastication?
Infratemporal fossa
What division of V3 provides sensory innervation to the mandible?
Inferior alveolar nerve
What is the path of the inferior alveolar nerve?
- Into the mandibular foramen
