Synovial joint
The joints are found at the junction between the different bones of the body. Contrary to popular belief, not all of them allow a wide range of motion, such as the hip joints.
Those of the skull do not allow any movement between the bones, while in others it is very limited, as in the Joints that is in the spine.
You wonder how the bones of the joints can stay in place. Well, this is produced thanks to the muscles and some strips of tissue that are called ligaments.
All freely moving joints - such as the fingers, hips, knee, and elbow - are called synovial joints, all of which have a similar structure in which a membrane (the synovial membrane) covers the joint producing a fluid that lubricates movement.
For their part, the ends of the bones are covered by a soft layer of Articular cartilage, which serves to minimize friction. The entire joint is inside a fibrous capsule, which helps it stay in place.