Osteology and Radiology of the Skull & The TMJ 3 - Viserocranium, Facial Fractures + TMJ Flashcards
What are the bones of the viserocanium
- zygomatic
- maxilla
- nasal
- lacrimal
- mandible
What bones of the viscerocranium are commonly fractured?
- nasal bone
- zygomatic bone + arch
- mandible
What x ray is used to look at mandibular fractures?
OPG
Orthopantomogram
Describe the temporomandibular joint
- articulation between temporal bone + mandible
- synovial hignge type joint
- divided into two synovial cavities by fibrocartilaginous disc
- innervation: auriculotemporal nerve
What conditions can affect the TMJ?
- TMJ disorder: pain(in ear/jaw/lateral head), clicking, locking
- dislocation: 2° to trauma, yawning
- arthritis
What is the innervation of the TMJ?
- auriculotemporal nerve
- branch of the mandibular division of trigeminal nerve Vc
Outline the anatomy of the TMJ
- articular surfaces of bones lined with fibrocartilage
- separated by fibrocartilaginous disc
- divides joint into two synovial lined cavities filled with synovial fluid
- stabilised by joint capsule + 3 extracapsular ligaments
What do the inferior + superior joint capsules of the TMJ allow for?
- inferior: rotation/hinge action
- superior: gliding movement
What actions occur in depression of the mandible?
- hinge/rotational action: inferior joint capsule
- gliding movement: superior joint capsule
What action occurs in retraction + protraction of the mandible?
gliding action at superior joint capsule
What muscles are involved in elevation of the mandible?
- masseter
- temporalis
- medial pterygoid
What muscles are involved in depression of the mandible?
- lateral pterygoid
- against resistance: platysma, suprahyoids assist
What muscles are involved in protraction of the mandible?
- lateral pterygoid
- medial pterygoid (assists)
What muscles are involved in retraction of the mandible?
posterior fibres of temporalis
What muscles are involved in grinding of the mandible?
muscles on both sides working together
