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Temporomandibular joint (TMJ)

The temporomandibular joint is a paired combined joint: movement on one side is invariantly associated without movement on the other. The joint has several unique features: (1) the articular surfaces (the condyle of the mandible and the mandibular fossa of the temporal bone) are covered with the specialized form of dense avascular connective tissue, distinct from the hyaline cartilage1, with a relatively high regenerative potential2; (2) the joint is supplemented with intra-articular fibrocartilage, which not only ensures the congruence of the articular surfaces but also follows the condyle of mandible both passively and actively, with the traction from the masticatory muscles3; (3) thanks to the articular disc, movements in the ellipsoid temporomandibular joint are possible in three directions. The mechanics of these movements are discussed separately.

  • 1 Hylander W. Functional anatomy. In: Laskin D, Sarnat B. The temboromandibular joint. A basis for clinical practice. 4th ed. Philadelphia: W.B. Saunders Company 1992:60-92.
  • 2 Robinson P. Articular cartilage of the temporomandibular joint: can it regenerate? Ann R Coll Surg Engl, 1993, 75(4):231–236.
  • 3 Hiraba K, Hibino K, et al. EMG activities of two heads of the human lateral pterygoid muscle in relation to mandibular condyle movement and biting force. J Neurophysiol, 2000, 83(4):2120–2137.
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    Articular surfaces of the TMJ (temporomandibular joint) Articular surfaces of the TMJ (temporomandibular joint)
    Art. temporomandibularis sin. Aspectus lateralis
    Click on the image to shift the mandible downward
    Note that the cartilaginous connective tissue of the mandibular fossa lines only the part that is in direct contact with the articular disc*. The posterior part of the fossa is covered only by periosteum.
    The list of terms
    Processus condylaris mandibulae Condylar process of mandible
    Condylus mandibulae Mandibular condyle
    Fovea pterygoidea Pterygoid fovea
    Collum mandibulae Neck of mandible
    Fossa mandibularis Mandibular fossa
    Facies articularis fossae mandibularis Articular surface of mandibular fossa
    Tuberculum articulare Articular tubercle
  • * Mohana-Borges A, et al. Ultrashort echo time magnetic resonance imaging of the temporomandibular joint (TMJ). In Du J, Bydder G (eds) MRI of short- and ultrashort- T2 tissues. 2023, Springer, 477–489.
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    Biomechanics of the temporomandibular joint (TMJ) Biomechanics of the temporomandibular joint (TMJ)
    Semi-schematic representation of the displacement of the joint capsule and articular disc of the temporomandibular joint during movement of the lower jaw
    Click on the image to switch the central occlusion to the maximal jaw opening
    The intra-articular disc of the temporomandibular joint is integrated into the capsule, so the finely calibrated deformation of the capsule and the disc movement are two interrelated processeses. An important anatomical feature here is the posterior part of the capsule, which in the neutral position is bilaminar (zona bilaminaris). As the condyle of the lower jaw slides forward, the bilaminar zone unfolds, while the elastic upper (temporal) lamina stretches, limiting the slipping and rotation of the disc1,2.
    The list of terms
    Discus articulationis temporomandibularis Articular disc of temporomandibular joint
    Cavitas superior articulationis temporomandibularis Superior cavity of temporomandibular joint
    Cavitas inferior articulationis temporomandibularis Inferior cavity of temporomandibular joint
    Membrana synovialis superior Superior synovial membrane
    Membrana synoviais inferior Inferior synovial membrane
    Zona bilaminaris Bilaminar zone
    Lamina superior (temporalis) Upper (temporal) lamina
    Lamina inferior Inferior lamina
  • 1 Bag A, et al. Imaging of the temporomandibular joint: an update. World J Radiol, 2014, 28;6(8):567–582.
  • 2 de Oliveira L, et al. Temporomandibular joint: from anatomy to internal derangement. Radiol Bras, 2023, 56(2):102–109.
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    Mandible and the articular capsule of the temporomandibular joint
    Cavitas superior articulationis temporomandibularis
    Fragments of muscles attached to the disc and capsule are preserved
    The articular disc fused with the capsule divides the cavity of the temporomandibular joint into two sealed compartments1 — the upper (cavitas superior) and the lower (cavitas inferior art. temporomandibularis). The image shows the superior synovial membrane and the upper surface of the articular disc facing the base of the skull. Note how the capsule fibers are merge into the anterior and posterior margins of the articular disc. It should be noted that the lateral edges of the disc are not attached to the capsule, but directly to the lateral and medial poles of the condyles of the mandible2.
    The list of terms
    Discus articulationis temporomandibularis Articular disc of temporomandibular joint
    Cavitas superior articulationis temporomandibularis Superior cavity of temporomandibular joint
    Capsula articularis Articular capsule
    Membrana synovialis superior Superior synovial membrane
    Caput superious m. pterygoidei lateralis Upper head of the lateral pterygoid muscle
    Pars profunda m. masseteris Deep part of the masseter
  • Tone L. Masticatory parafunctions and outcome of discectomy in the temporo-mandibular joint. Master of Medical Science in Odontology. 2006, Odontologiska Instituten, Stockholm
  • 2 de Oliveira L, et al. Temporomandibular joint: from anatomy to internal derangement. Radiol Bras, 2023, 56(2):102–109.
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    Inferior aspect of cranium with the articular capsule of the temporomandibular joint
    Cavitas inferior articulationis temporomandibularis
    & related masticatory muscles. Basal view
    The image allows us to see the inferior synovial membrane and the surface of the articular disc facing the condyle of the mandible. The mandible has been removed. The connection of the temporomandibular joint capsule with some masticatory muscles is exposed.
    The list of terms
    Discus articulationis temporomandibularis Articular disc of temporomandibular joint
    Cavitas inferior articulationis temporomandibularis Inferior cavity of temporomandibular joint
    Membrana synovialis inferior Inferior synovial membrane
    Caput superious m. pterygoidei lateralis Upper head of the lateral pterygoid muscle
    Pars profunda m. masseteris Deep part of masseter
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    Ligaments and articular capsule of the TMJ during mandibular motion
    Art. temporomandibularis et ligamenta temporomandibularia
    Aspectus lateralis
    Click on the image to switch the central occlusion to the maximal jaw protrusion
    The temporomandibular joint is strengthened by the medial and lateral temporomandibular ligaments. The lateral temporomandibular ligament is functionally distinct from the joint capsule1, whereas the medial ligament is most often described as a thickened portion of the joint capsule. It should be noted that there is currently no scientific consensus regarding the anatomical description, the terms used, or even the scientific validity of the medial temporomandibular ligament2.
    The list of terms
    Capsula articularis articulationis temporomandibularis Articuar capsule of the temporomandibular joint
    Lig. temporomandibulare laterale Lateral temporomandibular ligament
    Lig. temporomandibulare mediale Medial temporomandibular ligament
    Caput superious m. pterygoidei lateralis Upper head of the lateral pterygoid muscle
    Pars profunda m. masseteris Deep part of masseter
  • 1 Hill C et al. Structure-function relationships of TMJ lateral capsule-ligament complex. J biomech, 2021, 29;130.
  • 2 Fuentes R, et al. Review of the Tanaka ligament in the temporomandibular joint. analyzing its scientific validity. Int J Morphol, 2018, 36(1)
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    First published: 29.10.2024.