TMJ Anatomy Flashcards
The joint where the mandible articulates with the base of the cranium; Condyle of the mandible fits into –Squamous part of the temporal bone (MANDIBULAR FOSSA/GLENOID FOSSA/ARTICULAR FOSSA); Articular disc separates the two
TMJ
A ____ joint is one with 3 or more bones
Compound joints
What are the 3 “bones” that make the TMJ a compound joint?
Condyle, temporal, and articular disc
A ___ joint allows more than one type of movement
Complex joint
The TMJ is a ____ joint
Ginglymoarthrodial joint
_____ joint implies hinging movement permitted
Ginglymoid joint
___ joint implies gliding movement
Arthrodial joint
____ joint implies both hinging and gliding movements
Ginglymoarthrodial
____ joint Contains synovial fluid (Ex. contained in capsular ligament in TMJ); A sac surrounds the joint and keeps everything in place
Synovial Joint–
Do the posterior or anterior teeth separate faster in translation?
Posterior teeth
What phenomenon was observed in 1901 that shows the opening of the posterior teeth in mandibular protrusion?
Christensen’s phenomenon
___ is the creation of space between posterior teeth bilaterally during protrusion or on the balancing side during lateral excursions; protrusive and laterotrusive interocclusal records register the gap produced
Christensen’s phenomenon
What is the gap that happens during Christensen’s phenomenon caused by?
Temporal eminence
When the mandible moves to edge to edge position, separation occurs ____ between the natural dentition.
distally
The downward movement of the condyle down the articular eminence will result in the posterior teeth _____. This occurrence is explained by _______
Separating; Christensen’s phenomenon
___ of the TMJ is made of dense fibrous CT with no blood vessels or nerve fibers; divided into 3 section
Articular disc
Which section of the articular disc is the thinnest?; avascular, where condyle is located, rests on articular eminence
Intermediate zone
Which section of the articular disc is the thickest?
Posterior zone
What is the shape of the articular disc?
Bi-concave
Which part of the articular disc is concave?
Inferior part
Which part of the articular disc is concavo-convex
Superior part
What type of tissue is the articular disc?
Dense fibrous ct
Can the articular disc be the source of pain?
No; no nerve fibers
What is happening when the TMJ is clicking?
Disc and condyle are not moving in a coordinated fashion
Attaches the articular disc posteriorly to tympanic plate–Lots of elastic fibers–Stretches as joint is moved forward; pulls disc back in place
Superior retrodiscal lamina
Attaches disc to posterior inferior condyle margin–Composed of collagenous fibers, not elastic fibers–Attaches the inferior border of the posterior margin of the articular surface of the condyle; doesn’t allow disk to come off top of condyle
Inferior retrodiscal lamina
____ attachment of retrodiscal lamina connects disc to the tympanic plate; elastic fibers
Superior attachment
____ attachment of retrodiscal lamina attaches disc to neck of condyle; no elastic fibers
Inferior attachment
Attaches disc to the anterior margin of articular surface of temporal bone–Collagenous fibers
Superior Capsular Ligament CL
Attaches disc to anterior margin of condyle–Collagenous fibers
Inferior Capsular Ligament
Attachments of the capsular ligament between the superior and inferior capsular ligaments
Superior Lateral Pterygoid Muscle
Both the condyle and glenoid fossa have ____ connective tissue on articulating surfaces
Dense fibrous connective tissue
____ zone of articular surfaces: Most superficial layer. Unlike other synovial joints, this layer is made of dense fibrous connective tissue rather than hyaline cartilage: less susceptible to aging and better ability to repair
Articular Zone:
____ zone of articular surfaces: Contains undifferentiated mesenchymal cells and is responsible for proliferation of articular cartilage in response to loads.
Proliferative Zone:
____ zone of articular surfaces: 3D network of collagen offering resistance to lateral and compressive forces
Fibrocartilaginous Zone:
____ zone of articular surfaces: Made up of chrondrocytes and chrondoblasts. Active site for bone remodeling
Calcified Zone:
Movement is rotational in which compartment of TMJ
Inferior
Movement is translatory in which compartment of TMJ
Superior
Where does synovial membrane line in the TMJ?
Inner joint capsule and retrodiscal lamina
What are the 3 functional ligaments of TMJ?
Collateral/Discal ligaments–Capsular ligament–Temporomandibular ligament
What are the 2 accessory ligaments of TMJ?
Sphenomandibular ligament and Stylomandibular ligament
The articular disc is thicker on what portion of the condyle?
Medial
Which ligaments attach the disc to the medial and lateral poles of the condyle and to the surrounding capsule?
Discal/Collateral ligaments
Attaches medial edge of disc to medial pole of condyle
Medial Discal Ligament–
Attaches lateral edge of disc to the lateral pole of the condyle
Lateral Discal Ligament–
Which ligament is responsible for dividing the TMJ into 2 cavities?
Discal ligament
____ ligament surrounds the TMJ entirely; attached superiorly to temporal bone and inferiorly to condyle
Capsular ligament
Ligament that surrounds the joint like a curtain •Attached to the base of the skull and the condyle•Attached at the periphery of the articular parts •Also attached to the disc medially and laterally •Retains synovial fluid
Capsular ligament/ joint capsule
Is the bone thin or thick at superior part of glenoid fossa?
Thin
_____ states that bone in a healthy person or animal will adapt to the loads under which it is placed. If loading on a particular bone increases, the bone will remodel itself over time to become stronger to resist that sort of loading.
Wolff’s law
____ is the term used to describe the TMJ in a relaxed state
Centric relation
All areas of the joint not involved in articulation (internal surfaces of the cavities) are covered with _____ cells that form the synovial lining
specialized endothelial cells
____ lubrication: movement of fluid from one area of the joint cavity to another, prevents friction
Boundary lubrication:
______ lubrication: articular surfaces absorb some of the fluid, increased absorption during function, metabolic exchange
Weeping lubrication:
Which ligament attaches to the articular disc anteriorly, posteriorly, medially, and laterally?
Capsular ligament
Attaches the articular disc to the tympanic plate–Connective tissue–Lots of elastic fibers–Stretches as joint is moved forward
Superior Retrodiscal Lamina–
Collagenous attachment (not elastic)–Attaches the posterior of disc to the posterior margin of the articular surface of the condyle
Inferior Retrodiscal Lamina–
_____ joint cavity is Bordered by the –glenoid fossa –superior aspect of the disc; translatory movements
Superior Joint Cavity
____ joint cavity is Bordered by –inferior aspect of the disc–superior aspect of the condyle: rotates
Inferior Joint cavity
Tightening of which ligament will cause the condyle to translate?
Temporomandibular ligament
Thickening of the capsular ligament on the lateral aspect•Extends from articular tubercle and zygomatic process to the lateral pole and neck of the condyle, and the disk; 2 parts (outer oblique and inner horizontal); keeps mandible from going up into brain
Temporomandibular Ligament
Which part of the temporomandibular ligament causes translation?
Outer oblique portion
___ portion of Temporomandibular ligament Extends from the outer surface of the articular tubercle and zygomatic process posterior inferiorly to outer surface of condylar neck
•Outer oblique
___ portion of Temporomandibular ligament Extends from the outer surface of the articular tubercle and zygomatic process posteriorly–Horizontally to the lateral pole of the condyle and posterior part of the articular disc
Inner horizontal
___ portion of Temporomandibular ligament Prevents over rotation of the mandible–Causes translation of the mandible after 20-25 mm opening
Outer oblique
___ portion of Temporomandibular ligament Limits posterior movement onto the highly innervated retrodiscal tissue (PAIN)–Prevents excessive overextension of the lateral pterygoid muscle
Inner horizontal
_____ ligament prevents posterior movement of the mandible, the condyle will fracture before it can be driven posteriorly
Temporomandibular Ligament
____ ligament Arises from the Styloid Process•Inserts into the posterior border of the ramus of the mandible•Function: limits excessive protrusive movement of the mandible
Stylomandibular ligament
____ ligament Arises from the spine of the sphenoid bone•Inserts onto the medial surface of the ramus of the mandible called the lingula•Will tighten on rotation of the mandible, and will aid in the change from rotation to translations. Okeson says it has no role
Sphenomandibular Ligament
What is the state called when the muscles that pull across the joint (primarily elevators) are in a constant state of mild contraction
Tonus
As the inferior lateral pterygoid becomes active, ____will occur first in the inferior portion of the joint. When the inferior lateral pterygoid is active, the superior will be _____
rotation; inactive
The superior lateral pterygoid is only active during power strokes of the ____ muscles. When this muscle is active, the fibers that are attached to the disc pull ___ and __. The superior lateral pterygoid is technically a protractor of the disc.
elevator; anteriorly and medially
As the condyle descends down the articular eminence, the ________ becomes stretched
superior retrodiscal lamina
In translation, The disc is moved forward with the condyle, primarily due to the _____ ligament which attaches the disc to the anterior margin of the articular surface of the condyle. The condyle during movement seats more firmly against the disc on the intermediate zone.
anterior capsular ligament
What places a posterior pull on the disc as it translates; holds the disc rotated as far posteriorly on the condyle as the width of the articular disc space will permit?
Superior retrodiscal lamina
The space behind the condyle, the retrodiscal tissues, are rich in ____, and will fill the void left by the condyle by filling with ____.
veins; blood
Maximum opening is reached when the ____ ligaments prevent further movement at the condyles.
capsular ligaments
Maximum opening can be in the range of _____ mm when measure between the incisal edges of he maxillary and mandibular teeth.
40-60
____ syndrome is a rare condition commonly characterized but not limited to -sudden, sharp nerve-like pain in the jaw bone and joint, back of the throat, and base of the tongue, triggered by swallowing, moving the jaw, or turning the neck.
Eagle syndrome
First described by American otorhinolaryngologist Watt Weems Eagle in 1937, the condition is caused by an elongated or misshapen styloid process and/or calcification of the stylohyoid ligament, either of which interferes with the functioning of neighboring regions in the body, giving rise to pain.
Eagle syndrome
Symptoms of ____ include swallowing difficulties, a feeling that there is something stuck in the throat, shooting pains from the throat to the ear or jaw, pain at the base of the tongue, pain when swallowing or turning the head to one side, a persisting ringing or buzzing in the ears•a headache, throbbing in the jaw, Some people experience other symptoms, such as unusual sensations in the head or the neck.
Eagle syndrome
