Temporomandibular Joint

Structure

Ginglymoarthrodial (hinge plus gliding) synovial joint between the mandibular condyle and the mandibular fossa and articular eminence of the temporal bone.
Articular surfaces are covered by dense fibrous connective tissue (fibrocartilage), not hyaline cartilage.
The articular disc is biconcave: a thick posterior band, a thin avascular intermediate zone (where loading should happen) and an anterior band. It divides the joint into two spaces.
Posteriorly the disc attaches to retrodiscal tissue (bilaminar zone): vascular and innervated, so loading it is painful.
Innervation mainly by the auriculotemporal nerve (with masseteric and deep temporal branches of V3); blood from the superficial temporal and maxillary arteries.

Space	Movement	Phase of opening
Inferior (condyle–disc)	Rotation (hinge)	Early opening
Superior (disc–fossa/eminence)	Translation (gliding) forward onto the eminence	Later, wider opening and protrusion

Ligament	Attachments	Function
Temporomandibular (lateral)	Zygomatic arch/articular tubercle → condylar neck	Main TMJ ligament; limits posterior movement and rotational opening
Sphenomandibular	Spine of the sphenoid → lingula	Accessory; first-arch (Meckel's) remnant; landmark during an IANB
Stylomandibular	Styloid process → angle of the mandible	Accessory; limits excessive protrusion

Condition	Findings
Disc displacement with reduction	Reciprocal click (opening and closing); disc usually displaced anteromedially and recaptured
Disc displacement without reduction (closed lock)	No click, limited opening (often under about 35 mm), deviation toward the affected side
Dislocation (open lock)	Condyle trapped in front of the eminence; mouth stuck open; reduce by pressing down and back
Myofascial pain	Muscle tenderness and referred pain; most common TMD

Describing the TMJ surfaces as hyaline cartilage.
Placing translation in the inferior joint space: rotation is inferior, translation superior.
Calling the sphenomandibular ligament the main TMJ ligament: that is the lateral (temporomandibular) ligament.
Reducing a dislocation by pushing straight back: push down first, then back.

Pick an answer to see right away whether it is correct and why.

Which part of the articular disc is thinnest and normally bears load?
Translation of the condyle occurs mainly in which space?
A patient has sudden limited opening of 28 mm, no click, and deviation to the left on opening. The most likely diagnosis is:
Which ligament is a remnant of Meckel's cartilage?
Which nerve provides most sensory supply to the TMJ?

0 of 5 answered

Answer key: 1 C · 2 C · 3 C · 4 A · 5 C