Biology · Support and Movement

The periodontal ligament, commonly known as the PDL, is a soft connective tissue between the inner wall of the alveolar socket and the roots of the teeth. It consists of collagen bands (mostly type I collagen) connecting the cementum of teeth to the gingivae and alveolar bone. 

The radioulnar joint is located in the forearm between the radius and ulna bones. There are two radioulnar joints in the forearm: the proximal radioulnar joint and the distal radioulnar joint.

The tibiofibular joint is located in the lower leg between the tibia and fibula bones. It consists of two parts: the proximal tibiofibular joint and the distal tibiofibular joint.

Gomphosis is a specialized type of fibrous joint that refers specifically to the connection between a tooth and its socket in the jawbone. It is also known as a "peg-and-socket" joint. The term "gomphosis" comes from the Greek word "gomphos," meaning "bolt" or "nail". The connection in a gomphosis joint is extremely strong and allows for very little movement. This immovable connection is essential for the stability and function of the teeth in the mouth. The tooth is held securely in place within the socket by the periodontal ligament.

The periodontal ligament (PDL) is a specialized type of connective tissue that surrounds the roots of the teeth and attaches them to the surrounding alveolar bone within the jaw. It is located within the periodontal space, which is the small gap between the tooth root and the surrounding. The periodontal ligament is composed of collagen fibers, blood vessels, nerves, and other cellular components. It acts as a cushioning and shock-absorbing structure, allowing slight movement of the teeth during activities such as chewing. The PDL also plays a vital role in transmitting forces generated during chewing to the surrounding bone, helping to maintain the integrity of the tooth-supporting structures.