Normal Anatomy of the Temporomandibular Joint
Osseous Anatomy
Condyles are elliptical, not symmetrical nor identical
Wider medio-laterally than antero-posteriorly
Articular surface are the mandibular condyle and the articular tubercle of the mandibular fossa of squamous part of the temporal bone
Articular surfaces are covered by fibrocartilage
Soft Tissue Anatomy
Articular capsule-fibrous capsule
Attached to margins of temporal articular surface and tapers to attach to neck of condyle of mandible
Anteriorly attaches in front of the crest of articular eminence
Laterally attaches to eminence and fossa
Posteriorly runs along petrotympanic fissure
Medially runs along sphenosquamous suture
Lateral Temporomandibular Ligament
From lateral thickening fibrous capsule
Reinforces lateral part of capsule
Attaches to zygoma and runs to the back of the condyle below and behind the lateral pole
Stylomandibular Ligament
Band of cervical fascia
Runs from styloid process to posterior border mandible
Sphenomandibular Ligament
Separate from the articular capsule
Runs from spine of sphenoid bone to lingula on medial of mandible
Synovial Membrane
Lines fibrous capsule
Meniscus (Disk)
Three regions
Posterior band - 3 mm thick, continuous with posterior attachment tissues
Intermediate zone - 1 mm thick, continuous with retrodiscal pad
Anterior band - 2 mm thick, continuous with SLP capsule
Divides joint cavity into superior and inferior compartments
Fuses with articular capsule
Posterior attached tissues attached to posterosuperior part of temporal bone and posteroinferiorly to condyle
SLP may have fibers inserting directly into disc antero-medially
Disc more heavily attached to mandible and slides anteriorly on mouth opening