The type of joint at the point labelled 5 is a hinge joint.
A hinge joint is a type of joint that allows for movement in only one plane, like a door hinge. It consists of two bones that are connected by a strong ligament, which allows for movement back and forth in a single direction. The joint at point 5 appears to be between two long bones and allows for movement in one plane only, suggesting that it is a hinge joint.
In contrast, a ball and socket joint allows for movement in multiple planes and directions, like the shoulder joint. A pivot joint allows for rotational movement around a central axis, like the joint between the atlas and axis vertebrae in the neck. A gliding joint allows for sliding movements between flat surfaces of bones, like the joint between the carpal bones of the wrist.
Therefore, based on the location and type of movement, the joint at the point labelled 5 is most likely a hinge joint.