3. The Temporal Region and Temporomandibular Joint Flashcards
What does the infratemporal fossa contain?
Inferior part of temporalis muscle, and inferior parts of medial and lateral pterygoid muscles.
What is the maxillary artery a branch of?
External carotid artery, its larger terminal branch.
What is the middle meningeal artery a branch of?
The maxillary artery, which in term is a branch of the external carotid artery.
What is the superficial temporal artery a branch of?
The external carotid artery, its smaller terminal branch.
What are the veins of the infratemporal fossa?
Maxillary vein, middle meningeal vein, pterygoid venous plexus.
What is the mandibular nerve a branch of?
The trigeminal nerve, CN V3.
What are the branches of the mandibular nerve?
Auricular nerve, inferior alveolar nerve, lingual nerve, buccal nerve, chorda tympani (branch of facial nerve).
What are the openings of the infratemporal fossa?
Foramen ovale, foramen spinosum, alveolar canal, inferior orbital fissure, pterygomaxillar fissure.
What runs through the foramen ovale?
Mandibular division of the trigeminal nerve CN V3.
What runs through the foramen spinosum?
Middle meningeal artery.
What is mandibular nerve block?
Injection of anaesthetics near the mandibular nerve where it enters the infratemporal fossa near the foramen ovale.
Which nerve are affected in mandibular nerve block?
Inferior alveolar, lingual, buccal, auriculotemporal.
When are inferior alveolar nerve blocks used?
In dental procedues.
What happens in an inferior alveolar nerve block?
Anaesthetic is injected around the mandibular foramen on the medial side of the mandible, where inferior alveolar nerve and vessels travel.
What is anaesthetised in inferior alveolar nerve block?
All mandibular teeth on medial side, skin and mucous membranes of lower lip, labial alveolar mucosa, gingivae, skin.
What type of joint is the temporomandibular joint?
Modified hinge type synovial joint.
What are the bones in the temporomandibular joint?
Mandible and cranium.
What are the superior surfaces in the TMJ?
Mandibular fossa - posterior and concave, and articular tubercle - anterior and convex.
What is the inferior surface in the TMJ?
Head of the mandible.
What is the articular disc of the TMJ?
Aka meniscus. It is made of tough fibrocartilage and creates two compartments - superior and inferior articular cavities lined by separate synovial membranes.
What are the movements of the TMJ?
Flexion (closing mouth), extension (opening mouth), gliding (protrusion/retrusion of mouth), rotation (pivoting).
Which muscles are involved in flexion/elevation of the TMJ?
Temporalis, masseter, medial pterygoid.
Which muscles are involved in extension/depression of the TMJ?
GRAVITY, lateraly pterygoid, suprahyoid, infrahyoid.
Which muscles are involved in gliding/translation of the TMJ?
Protrusion - lateral pterygoid, medial pterygoid, masseter.
Retrusion - temporalis, masseter.
Describe the movements in opening the TMJ.
Condyles are pulled forwards in protrusion. The chin moves down and back in hinge movement.
Describe the movements in closing the TMJ.
Retraction of the mandible by retrusion. Elevation of the mandible by hinge movement.
What is the joint capsule of the TMJ like?
Loos and thin to permit movements of the joint but strengthened by extra-capsular ligaments.
What are the attachments of the TMJ capsule?
Superiorly - circumference of the mandibular fossa and articular tubercle.
Inferiorly - neck of the condyle of the mandible.
What are the extra-capsular ligaments of the TMJ?
Lateral - one ligament ‘temporomandibular ligament’ strong, deep fibres blend with capsule.
Medial - two accessory ligaments ‘sphenomandibular ligament’ and ‘stylomandibular’ ligament.
What is the TMJ most stable and why?
Why the jaw is closed as the mandibular condyle is in contact with the mandibular fossa. The teeth are in occlusal contact.
When is the TMJ least stable?
When the jaw is open.
How can anterior dislocation of the TMJ occur?
During yawning or a large bite, excessive contraction of the lateral pterygoids cause head of mandible to dislocate anteriorly.
How does anterior dislocation of TMJ present?
Lock jaw, patient can’t close their mouth.
What is the most common cause of dislocation of the TMJ?
Side-ways blow to the chin with open mouth so TMJ dislocates on side that receives blow.
What is bruxism?
Grinding teeth when asleep.
What is temporomandibular pain dysfunction disorder?
Muscular pain.
What is mal-occlusion syndrome?
Muscular pain.
