ArticolazioneTemporo-mandibolare — Transcript

Anatomy, locomotor system. In this video, we will discuss the joints of the skull. However, most of them are sutures and have already been described when we talked about the skull as a whole. For this reason, in this video, we will see the only

mobile joint of the skull, the temporomandibular joint. The temporomandibular joint is formed between the temporal bone and the condyle of the mandible.

It is mainly a condylar joint, as the condyle of the mandible acts as the condyle, and the condylar cavity is formed by the mandibular fossa located inside the temporal bone.

In this image, we can observe the two bony heads in the way they come into contact with each other. As you can see, the condyle is not oriented on the sagittal plane but rather on the frontal plane.

Since the condylar cavity is not a cavity that perfectly fits the structure of the joint, a flap is interposed between the two bony heads, a flap called the articular disc or glenoid labrum, whose function is to deepen the cavity and facilitate sliding between the two bony heads.

As you can observe, this joint allows a rotational movement, mainly in this direction, favoring the biting movement in animals. In humans, the biting movement has a much smaller amplitude because humans are not carnivores but omnivores, so they need less jaw opening.

Moreover, this type of joint also allows a minimal movement on the frontal plane. This lateral movement is an inheritance from herbivores, as humans, being omnivores, only need small movements on the other plane to grind vegetables. So, the human masticatory system is a hybrid between a purely carnivorous system and a purely herbivorous system.

This type of response has been observed in several omnivorous animals. The temporomandibular joint has means of fixation that we can observe in this image. The first means of fixation, clearly, is represented by the articular capsule. The articular capsule always has a synovial layer and a fibrous layer. The fibrous layer attaches to the neck of the mandibular condyle, and on the temporal bone, its attachment is more complex because, as you can see, it takes the entire perimeter of the mandibular fossa, also attaching to the zygomatic process of the temporal bone, and on the inferior face, it covers a good part of the temporal pyramid almost up to the carotid foramen.

This is the articular capsule. The outermost face of the articular capsule, however, thickens and almost detaches from the normal capsule, becoming a structure on its own: the lateral ligament or lateral temporomandibular ligament. This ligament is practically a thickening of this portion of the capsule. Its function is precisely to strengthen the junction between the two bones.

At the same time, other ligaments exist in this joint. The other ligaments are internal to the mandible. We have the sphenomandibular ligament, which originates from the spine of the greater wing of the sphenoid bone and inserts bifurcating at the level of the mylohyoid fossa. And the stylomandibular ligament, which originates from the styloid process of the temporal bone and inserts on the posterior face of the angle of the mandible.

Among the ligaments of this joint, although not shown here, is the pterygomandibular ligament, an aponeurotic fascia that originates from the outer lamina of the lateral pterygoid process and extends to the inner face of the angle of the mandible. These three ligaments function to keep the mandible stable within the joint. This video was made with the help of Anatomy Learning, an interesting web app whose link you can find in the description.

sul processo zigomatico dell'osso temporale e sulla faccia inferiore va a rivestire buona parte della piramide del temporale fin quasi al foro. carotico.

Questa è la capsula articolare. La faccia più esterna della capsula articolare però si spessisce e prende quasi il distacco dalla capsula normale diventando una struttura a sé. Il legamento laterale o legamento temporomandibolare laterale. Questo legamento è praticamente un ispessimento

della di questa porzione di capsula. La sua funzione è appunto quella di rafforzare la giunzione tra le due ossa.

Contemporaneamente però esistono altri legamenti in questa articolazione. Gli altri legamenti sono costituiti da legamenti interni rispetto alla mandibola. Abbiamo il legamento sfeno mandibolare che origina dalla spina della grande ala dell'ossosfenoide per andarsi a inserire biforcandosi a livello della fossa

miloioidea. E il legamento stilomandibolare che origina dal processo stiloideo dell'osso temporale per inserirsi sulla faccia posteriore dell'angolo della mandibola.

Può essere annoverato tra i legamenti di questa articolazione, benché qui non è rappresentato, il legamento pterigo mandibolare, una fascia aponeurotica che origina dalla lamina esterna del processo pterigoideo laterale e si porta sulla faccia interna dell'angolo della mandibola. Questi tre

legamenti hanno la funzione di mantenere la mandibola ferma all'interno dell'articolazione. Questo video è stato girato con l'ausilio di Anatomy Learning, un interessante web app il cui link lo trovate in descrizione.