Temporomandibular Joint Dysfunction Flashcards
TMJ dysfunction and Revision of anatomy of TMJ
What are some nomenclature for temporomandibular dysfunction?
- Myofascial pain dysfunction
- Pain dysfunction syndrome
- Facial arthromyalgia
- Costen’s syndrome
- TMJ
What are the suprahyoid muscles? (Accessory muscles of mastication)
- Digastric
- Mylohyoid
- Geniohyoid
- Stylohyoid
Name the infrahyoid muscles (Accessory muscles of mastication)
- Thyrohyoid
- Sternohyoid
- Omohyoid
- Sternothyroid
What is the origin and insertion of the masseter muscle? What is its action? What is its innervation? What is its blood supply
- Origin has two places on Zygomatic arch
Superficial origin : maxillary process of zygomatic bone, inferior border or zygomatic arch (anterior 2/3rd)
Deep origin : deep/inferior surface of zygomatic arch (posterior1/3rd) - Insertion onto lateral surface of ramus and angle of mandible
Function : Elevates and protrude mandible
Innervation : masseteric nerve of mandibular nerve CN V3
Blood supply : Masseteric artery
What is the origin and insertion of temporalis muscle? What is its action? What is its innervation? What is its blood supply
Originates : from temporal fossa and deep part of temporal fascia
Insertion : Apex and medial surface of coronoid process of mandible
Function : Anterior fibres elevate mandible
Posterior part retracts mandible
Innervation : Deep temporal branches of mandibular nerve CN V3
Blood supply : Deep temporal branches of maxillary artery, middle temporal branches from superficial temporal artery
What is the origin and insertion of medial pterygoid muscle? What is its action? What is its innervation? What is its blood supply
Superficial origin : tuberosity of maxilla, pyramidal process of palatine bone
Deep origin : Medial surface of lateral pterygoid plate of sphenoid bone
Insertion : Medial surface of ramus and angle of mandible
Function : Bilateral contraction elevates and protrudes mandible
Unilateral contraction medial movements (rotation) of mandible
Innervation : Medial pterygoid nerve of mandibular nerve CN V3
Blood Supply : Pterygoid branches (max artery, buccal artery, facial artery)
What is the origin and insertion of lateral pterygoid muscle? What is its action? What is its innervation? What is its blood supply
Superior head origin : infratemporal crest of greater wing of sphenoid bone
Inferior head origin : Lateral surface of lateral pterygoid plate of sphenoid bone
Superior head insertion : Joint capsule of TMJ
Inferior head insertion : Pterygoid fovea on neck of condyloid process of mandible
Function : Bilateral contraction protrudes and depresses mandible whilst stabilises condylar head during closure
Unilateral contraction medial movement of mandible
Innervation : Lateral pterygoid nerve of mandibular nerve CN V3
Blood supply : Pterygoid branches of maxillary artery, ascending palatine branch of facial artery
What parts of the articular disc is innervated and can feel pain from?
- Only the bilaminar zone is innervated
- Articular tissues and dense part of articular disc no nerve supply
- Feel pain when bilaminar zone is compressed by condylar head or stretched when disc is moved
Label this diagram of the right hand side mandible
Label this internal view of mandible
What branches does the mandibular nerve split into?
- Buccal nerve (Anterior division)
- Auriculotemporal nerve (post_
- Inferior alveolar nerve (post)
- Lingual nerve (post)
What does the inferior alveolar nerve divide into?
- Nerve to mylohyoid (before entering mandibular foramen)
- Incisive nerve
- Mental nerve
- Inferior dental plexus
Label this diagram
What type of joint is the temporomandibular joint? What is the TMJ?
- Hinge type synovial joint that connects the mandible to the rest of the skull
- It is an articulation between the mandibular fossa and the articular tubercle (eminence) of the temporal bone, and the condylar process of the mandible
Why is the TMJ classed as atypical?
- Classed as synovial type joint but it is atypical in that its articular surfaces lined by fibrocartilage rather than hyaline cartilage
What is the main function of TMJ? What movements can the joint do?
- To facilitate movements of the lower jaw
- Allows range of movement of lower jaw, namely translational movements (protrusion / retraction and lateral deviation) and rotational movements (elevation and depression)
What are the main bones involved in formation of TMJ and what do they form?
- Inferior part of joint formed by condylar head of mandible
- Superior part of joint formed by mandibular fossa and articular tubercle on the Temporal bone
Called articular surfaces
What structure lies between the two articular surfaces of the TMJ? What is it’s function?
- Articular disc of TMJ
- Separated the articular surfaces
- Disc stabilised condyle of mandible within join , reduces frictional force between articular surfaces and may aid lubrication of joint
How Does movement occur in the TMJ?
Superior compartment allows translation movements
- protrusion
- Retraction
- Left and right lateral deviation
Inferior compartment allows rotational movement
- Depression
- Elevation
- Both rotation and translation occur simultaneously therefore allow complex movements that allow people to chew and talk
What is the blood supply of the TMJ?
- Deep auricular artery (form maxillary artery)
- Superficial temporal artery (terminal branch of external carotid artery)
- Anterior tympanic artery (branch of maxillary artery)