Temporo-mandibular Articulation

Bones Involved

• Glenoid fossa of the temporal bone
• Condyle of the mandible

Articulatory System

• 2 articular surfaces: upper roof and lower floor
• Upper roof: 2 parts of temporal bone
• Lower floor: superior surface of disc
• Roof: inferior surface of disc
• Floor: articulating surface of the mandibular condyle

Temporo-mandibular Joint (TMJ)

• Definition: a diarthrodial freely movable articulation between the condyle of the mandible and squamous part of the temporal bone
• Classification: synovial joint, bilateral condylar variety
• Types of movement: hinging or rotation movement in one plane, sliding movement

Articular Eminence

• Small prominence in the zygomatic arch
• Strongly convex anteroposteriorly and concave mediolaterally
• Serves as a major functional component of the TMJ

Articular Tubercle (Postglenoid Tubercle)

• Non-articulating process on the lateral aspect of the zygomatic root of the temporal bone
• Serves as a point of attachment of collateral ligaments

Glenoid Fossa

• Anterior articular area formed by the inferior aspect of temporal squama
• Smooth and oval surface

Mandibular Component

• Ovoid condylar process (head) with narrow mandibular neck
• Rounded mediolaterally and convex anteroposteriorly
• Broad laterally and narrow medially

Articular Disc

• Morphology: biconcave, sagitally thicker anteriorly and thinner posteriorly, oval, avascular, and non-innervated in the middle
• Derived from mesoderm of 1st pharyngeal arch
• Divided into 3 general regions: anterior band, central intermediate zone, and posterior band

Function of Articular Disc

• Stabilization of the TMJ
• Reduces wear on the joint

TMJ Ligaments

• Functional ligaments: collateral, capsular, and lateral
• Accessory ligaments: sphenomandibular, stylomandibular, and mandibulo-malleolar (Pinto's ligament)
• Serve as passive restraints on mandibular motion