TMJ Anatomy/Biomechanics Review Flashcards
ARTICULAR STRUCTURES
ARTICULAR STRUCTURES
- The TMJ is between the mandibular _________ and the mandibular fossa of the ___________ bone.
- Anteriorly, the disc is attached to what?
- Posteriorly, the disc is attached to what?
- condyle, temporal
- anterior capsule and lateral pterygoid
- retrodiskal laminae
The TMJ capsule is thin _______/________ and thickened ________/________ by collateral ligaments.
- anterior/posterior
- laterally/medially
The TMJ disc is a bi-_______, flexible fibrocartilaginous structure with anterior, posterior, and intermediate bands.
-bi-concave
What is the function of the TMJ disc?
- Seperates the joint cavity into 2 functional components.
- Allows dispersion of forces.
- The TMJ upper joint is a plane gliding joint for _________ of mandibular condyles.
- The TMJ lower joint is a hinge joint that permits _______ of condyles.
- translation
- rotation
- The __________ laminae is a ligament from the temporal bone to the posterior border of the disc.
- There is a __________ network within these elastic fibers.
- These are elastic fibers that aid in disc recoil during mouth ________.
- retrodiscal
- neurovascular
- closing
What are the functions of the retrodiscal laminae?
- Stabilize the disc.
- Prevents excessive translation of the disc over the condyle.
- With anterior dislocation of the disc, the highly innervated laminae may be approximated between the mandibular condyle and mandibular fossa.
The ______________ ligament is a thickening of the anterior joint capsule from the neck of the mandible to the zygomatic arch.
tempromandibular ligament
The tempromandibular ligament helps prevent __________ dislocation of the joint, prevents _______ slippage of the disc, and counters the _______ _________ pull.
- posterior
- medial
- lateral pterygoid
MUSCULATURE
MUSCULATURE
What are the muscles of mastication?
- Temporalis
- Masseter
- Medial Pterygoid
- Lateral Pterygoid
What are the suprahyoid muscles?
- Stylohyoid
- Digastric
- Geniohyoid
- Mylohyoid
What are the infrahyoid muscles?
- Thyrohyoid
- Sternothyroid
- Sternohyoid
- Omohyoid
Temporalis:
- Origin?
- Insertion?
- Action?
- Origin- temporal fossa
- Insertion- coronoid process on anterior ramus of mandible
- Action- elevate mandible
Masseter:
- Origin?
- Insertion?
- Action?
- Origin- inferior and medial zygomatic arch
- Insertion- coronoid process of lateral ramus of mandible
- Action- elevation and protrusion of mandible
Medial Pterygoid:
- Origin?
- Insertion?
- Action?
- Origin- medial surface of lateral pterygoid plate, pyramidal process of palatine bone, tuberocity of maxilla
- Insertion- medial aspect of mandibular ramus
- Action- elevate and protrusion of mandible
Lateral Pterygoid:
- Origin?
- Insertion?
- Action?
- Origin- superior head to lateral surface of greater wing of sphenoid bone, inferior head to lateral surface of lateral plate
- Insertion- neck of mandible, articular disc, TMJ capsule
- Action- protrude and depress mandible, lateral deviation of mandible
- What muscles close the mouth?
- What muscles open the mouth?
- Close = temporalis, masseter, medial pterygoid
- Open = lateral pterygoid
The infrahyoid muscles are innervated by branches of C_-C_ and act to ________ the hyoid.
- C1-C3
- depress
The suprahyoid muscles act to _______ the hyoid. The _______ depresses the mandible against resistance and elevates the hyoid.
- elevates
- digastric
NORMAL BIOMECHANICS
NORMAL BIOMECHANICS
During mouth opening, the first half of motion is a _______ that occurs at the ______ portion of the TMJ.
- rolling
- lower
During mouth opening, the second half of motion is a __________ __________ along the temporal bone in the _______ portion of the TMJ.
- anterior translation
- upper
As the joint moves anteriorly, it also moves ___________, resulting in what?
- inferiorly
- greater mouth opening, separation of teeth
NEUROVASCULAR STRUCTURES
NEUROVASCULAR STRUCTURES
The __________ nerve is a branch of the trigeminal nerve that provides motor innervation to the muscles of mastication.
-mandibular
What is the sensory input from the mandibular nerve?
Teeth, temporal region, external auditory meatus, tympanic membrane, lower lip, lower face, mucosa anterior 2/3rds of the tongue, floor of oral cavity
The _________ artery comes off of the external carotid artery to provide for structures of the TMJ.
maxillary
ARTHROLOGY
ARTHROLOGY
The disc functionally seperates the TMJ into _______ and _____ joint cavities.
upper and lower
- 50% of motion occurs as rolling in the _______ joint.
- During this, the _________ moves on the ____________.
- The disc remains _____________.
- lower
- condyle on temporal bone
- stationary
- 50% of motion occurs as gliding in the ______ joint.
- This portion begins at ____-opening.
- The disc is pulled ____________ by the _______________.
- The condyle moves along the sigmoid shaped ______________.
- The disc ________ along with the condyle.
- upper
- mid-opening
- anteromedially, lateral pterygoid
- temporal bone
- slides
Normal Osteokinematic Motion:
- Opening?
- Lateral Deviation?
- Protrusion?
- Retrusion?
- Opening = 35-50mm
- Lateral Deviation = 10-15mm
- Protrusion = 3-6mm
- Retrusion = 3-4mm
- What is the resting position of the TMJ?
- What is the close-packed position of the TMJ?
- slight opening
- fully closed
