Anatomy joints

Movement of bone vertically downwards.

Fibrous mobile peg-and-socket joint of a tooth with its bony socket.

The movement of the lower jaw to the side.

The place where the bone and the ligaments are joined together.

Relating to or affecting tissues and structures around the teeth - Greek "peri" = around and "odontos" = tooth.

A bony projection.

Movement of a joint horizontally forwards.

Joint in which bones grow together and are linked by a disc of fibrocartilage.

Joint in which bones are linked together by hyaline cartilage.

Fusion of a normally separate skeletal bones - Greek "syn" = together and "osteon" = bones.

Synovial, Fibrous, Cartilaginous

Hinge: Hinge joints (Figure a) are uniaxial, like the hinge on a door. Their movement is restricted to one plane by the shape of the opposing articular surfaces, as well as the strong collateral ligaments along the sides of the joint.E.g.The knee joint

Gliding: Gliding joints (Figure b) are uniaxial. Their articular surfaces are flat and glide over each other.E.g. The intercarpal bones.

Pivot: Pivot joints (Figure c) are uniaxial and consist of a bony pivot (projection) within an osteo ligamentous ring.E.g. The superior radioulnar joint.

Saddle: Saddle joints (Figure a) are biaxial, with both bones possessing concavoconvex surfaces, which means that each surface is concave in one direction and convex in the other direction.E.g. The carpometacarpal joint of the thumb.

Condyloid: Condyloid joints (Figure b) are biaxial, with a convex condyle that fits into a concave surface. They do not allow rotation.E.g. The metacarpophalangeal joints.

Ball and socket: Ball and socket joints (Figure c) are multiaxial and the most flexible joints in the body. They consist of a hemispherical head that fits into a cup-like depression.E.g. The glenohumeral joint.

Suture: A suture is a strong immovable fibrous joint. The bones are joined together by a fibrous sutural ligament that becomes continuous with the periosteum of the bones. These joints can interlock like a puzzle or consist of relatively straight non-overlapping edges. A sutural ligament is a membrane that binds the individual bones of the cranium together. Sutures are only found in the junctions between the plate bones of the skull.

Gomphosis: A gomphosis is formed by a peg like process fitting into a socket. These joints give only a little to act as shock absorbers and sensors. It is only found connecting teeth to their sockets. The periodontal membrane is a fleshy layer of tissue that lies between the tooth and the alveolar sockets of the maxilla or mandible. The membrane keeps the tooth in the socket forming the fibrous gomphosis joint and enables the tooth to resist the stresses of chewing.

Syndesmosis: This joint occurs where bones are bound together by an interosseous ligament consisting of long collagenous fibers. They allow a little movement. An example is the interosseous membrane between the shafts of the radius and ulna. There are two interosseous membranes in the body, and they consist of sheets of fibrous fascia located between the interosseous borders of the shafts of the radius and ulna, and the tibia and fibula.

• Synchondrosis:

is a joint composed of two bone that are joined by hyaline cartilage.

• Symphysis:

is where two bones are joined together by a fibrocartilage disc.