2nd Session: Anatomy of the TMJ (1-15, Astorga) Flashcards
What is the Masticatory System responsible for?
Chewing, speaking, swallowing
Masticatory system: name the skeletal components (MMT)
Mandible Maxilla Temporal
Masticatory system: name the muscle components (6)
Masseter Temporalis Superior Lateral Pterygoid Inferior Lateral Pterygoid Medial Pterygoid Digastric
Masticatory system: name the ligament components (CCTSS)
Collateral Capsular Temporomandibular Sphenomandibular Stylomandibular
Name the main parts of the mandible bone:
Condyle, Coronoid Process, Ramus, Mandibular Notch, Mental Foramen, Body
Name the anatomy on the temporal bone:
Mastoid Process
External Acousitc Meatus
Styloid Process
Glenoid fossa
Articular Eminence
Zygomatic Process
Squamous Portion
Name the main anatomy of the maxilla bone:
Frontal Process,
Infraorbital Foramen,
Anterior Nasal Spine,
Alveolar Process, Body,
Tuberosity,
Infratemporal Surface,
Zygomatic Process
Name the Origin, Insertion, Function, Vascularity, and Innervation of the masseter muscle.
O: Zygomatic process of the maxilla
I: Angle of the mandible
F: Elevation of the mandible & protrusive
Vas: masseteric artery
Innerv: Masseteric branch of CNV (Trigeminal)
Name the Origin, Insertion, Function, Vascularity, and Innervation of the temporalis muscle.
O: Temporal fossa
I: coronoid process and anterior border of the ascending ramus
F: elevation of the mandible and retrusion
Vas: anterior, posterior, and superficial temproal arteries
Innerv: Deep temporal nerve from the mandibular branch of CNV (trigem)
Name the Origin, Insertion, Function, Vascularity, and Innervation of the lateral superior pterigoid muscle.
O: Lower part of the lateral surface of the great wing of the sphenoid and from the intratemporal crest.
I: The neck of the condyle and the anterior margine of the DISC!
Function: stabilizes the condyle and disk curing mandible loading (unilateral chewing)
Vas: Pterygoid branch of the maxillary artery
Innerv: mandibular branch of the CNV (trigem)
Name the Origin, Insertion, Function, Vascularity, and Innervation of the inferior lateral pterigoid muscle.
O: lateral surface of the lateral pterygoid plate
I: neck of the condyle
function: protrudes the mandible, contributes to the lateral movements and mouth opening
vas: pterygoid branch of the maxillary artery
Inn: mandibular branch of the CNV (trigem)
Name the Origin, Insertion, Function, Vascularity, and Innervation of the medial pterygoid:
O: medial surface of lateral ptrygoid plate and the pyramidal process of the palatine bone.
I: inferior and posterior of the medial surface of the ramus and angle of the mandible
Function: elevation of the mandibl and contributes of protrusion
Vas: pterygoid branch of the maxillary artery
Innerv: mandibular branch of the CNV (trigem)
Name the Origin, Insertion, Function, Vascularity, and Innervation of the anterior digastric muscle:
O: digastric fossa
I: Hyoid bone
Function: depression of the mandible and elevation of the hyoid bone
Vas: submental artery
Innerv: Mandibular branch of the CNV
Name the Origin, Insertion, Function, Vascularity, and Innervation of the posterior digastric muscle:
O: mastoid notch
I: hyoid bone
function: depression and elevation of the hyoid bone
vas: lingual and facial artery
Innerv: digastric branch of the CNVII (facial)
Do ligaments stretch?
Nope! But they can elongate over time, which compromises their function.
What is the main way that ligaments function?
Ligaments are not an active functional component of joints, but act as passive restraining devices to limit and restric border movements.
What are the three funciton ligaments that support the TMJ?
Collateral Ligaments
Capsular Ligaments
Temporomandibular Ligament (TML)
(The sphenomandibular and stylomandibular ligaments are accessory)
What does the collateral ligament do?
Attaches the medial and lateral borders of the articular disk (MDL And LDL) to the poles of the condyle:
medial discal ligament (MDL)
and
lateral discal ligament (LDL)
Note: these two divide the joint mediolaterally in the superior and inferior joint cavities.
What is the role of the capsular ligament?
Surrounds and encompasses the temporal mandibular joint.
Attach: superiorly to temporal bone @ mandibular fossa and articular eminenece, @ neck of the condyle.
Resists medial, lateral, or inferior forces that serparate or dislocate the articular surfaces.
Also, retaines synovial fluid.
Note: well innervated, so provides proprioceptive feedback for the joint
What is the role of the temporomandibular ligament?
Composed of 2 parts:
outer oblique portion- from articular tubercle & zygomatic process to condylar neck
inner horizontal portion - from articular tubercle & zygomatic process to lateral pole of the condyle & articular disk Protects the retrodiscal tissues from trauma created by the posterior displacement of the condyle, and protects the lateral pterygoid muscle from over-extension.
How far can the mouth separate before the condyles move from the fossae?
20-25 mm
Which ligament forces the condyle to move downward and forward out of the fossa as it is opened past 25mm?
The outer portion of the temporomandibular ligament.
Accessory ligament: what is the role of the sphenomandibular ligament?
No significant limiting effects on mandibular movement. From the spine of hte sphenoid bone and extends down toward to the lingula on the mandible.
Accessory ligament: what is the role of the stylomandibular ligament?
Becomes taught when mandible is protruded, but relazed when mandible is opened. So, it limits excessive protrusive movements of mandible. Attaches to styloid process and extends to the angle and ramus of the mandible.
Describe the anatomy of the articular disk:
Composed of dense fibrous connective tissue WITHOUT blood vessel and nerve fibers.
What are the 3 zones of the articular disk (from sagittal view)?
- Anterior portion. Thick area attached to the superior pole of the laeral pterygoid muscle.
- Intermediate. Thinnest area.
- Posterior. Thick area attached to loose connective tissue that is highly vascularized and innervated.
Horizontal view of the TMJ: how are the condyles angled?
If an imaginary line were drawn through lateral and medail poles, would extend medially and posteriorly toward the foramen magnum.
