Temporomandibular Joint Flashcards
What separates the articular surfaces of the TMJ so that they never come into contact?
Articular disk
Splits it into two synovial joint cavities, each lined by a synovial membrane
What are the articular surfaces of the TMJ lined with?
Fibrocartilage
Name the three ligaments of the TMJ and give each one’s function
Lateral aka temporomandibular - prevent posterior dislocation
Sphenomandibular - prevent inferior dislocation
Stylomandibular - supports the weight of the joint along with the facial muscles
Function of the stylomandibular ligament?
Separated the parotid gland from the submandibular gland
PICTURE Where does the lateral ligament run from and to?
From the beginning of the articular tubercle to the mandibular neck
It is a thickening of the joint capsule
Where does the sphenoidmandibular ligament run from and to?
From the sphenoid spine to the mandible
Where does the stylomandibular ligament run from and to?
Thickening of the fascia of the parotid gland
What are the movements of the TMJ?
Protrusion and retraction
Elevation and depression
What are the movements of the TMJ generally produced by?
Muscles of mastication
Hyoid muscles
Which muscles carry out protrusion and retraction of the TMJ?
Protrusion - lateral pterygoid
Retraction - geniohyoid and digastric
Which muscles carry out elevation and depression of the TMJ?
Depression - gravity. If there is resistance, digastric, geniohyoid and mylohyoid muscles
Elevation - temporalis, masseter, medial pterygoid muscles
How can dislocation of the TMJ occur?
Blow to the side of the face
Yawning, large bite
What happens in a dislocation of the TMJ?
Head of mandible slips out of the mandibular fossa and pulled anteriorly over the articular tubercle - patient unable to close their mouth
What can be damaged in a dislocation of the TMJ?
Facial and auriculotemporal nerves
Why are posterior dislocations of the jaw rare?
Need to overcome the postglenoid tubercle and the strong intrinsic lateral ligament
