Temporomandibular joint

Let’s learn about the structure of the temporomandibular joint (articulatio temporomandibularis).

The bones forming the joint are the temporal bone (os temporale) and the mandible (mandibula).

The articular surfaces involved in the formation of the joint are the mandibular fossa and the articular tubercle of the temporal bone (fossa mandibularis et tuberculum articulare ossis temporalis),

as well as the head of the mandible (caput mandibulae).

The articular capsule is attached to the temporal bone along the articular tubercle in front, and along the petrotympanic fissure behind. On the mandible, the capsule is attached along the neck (0.5 cm higher in front than behind); at the same time, it is thin in the anterior part, and dense, fibrous in the posterior part, so dislocations of the mandible are possible only in the forward direction.

Articular tubercle (cavitas articularis)

According to the classification, the joint is simple, combined and condylar.

The following range of motions is possible in the joint:

Around the frontal axis, it lifts and lowers of the mandible
Around the vertical axis, it performs rotation (rotatio) of the mandible to the right and left
Around the sagittal spine, it shifts the mandible back and forth
When rotating, the mandible shifts: on its side, rotation is carried out in the fossa, on the opposite side, the mandible shifts to the tubercle.
Several ligaments belong to the fixing apparatus of the joint.
Lateral ligament (ligamentum laterale)
Lateral ligament (ligamentum laterale)
Stylomandibular ligament (ligamentum stylomandibulare)
Stylomandibular ligament (ligamentum stylomandibulare)
Sphenomandibular ligament (ligamentum sphenomandibulare)
Sphenomandibular ligament (lig. sphenomandibulare)
The additional structures of the joint include the articular disc (discus articularis).
Articular disc (discus articularis)
How the muscles affect the joint:
Lowering: m. digastricus (venter anterior), m. geniohyoideus, m. mylohyoideus.
Lifting: m. masseter, m. pterygoideus medialis.
Medial pterygoid muscle (musculus pterygoideus medialis)
Anterior motion: m. pterygoideus lateralis
Posterior motion: posterior bundles of m. temporalis
Side motion: m. pterygoideus lateralis (in the opposite direction)
Lateral pterygoid muscle (musculus pterygoideus lateralis)
The following vessels and nerves take part in the blood supply and innervation of the joint.
Arteries: a. auricularis profunda of a. maxillaris
Veins: rete articulare mandibulare further into plexus venosus pterygoideus, then into v. jugularis interna
Nerves: n. auriculotemporalis