Final answer:
The three types of action/functional joints are immovable joints, partially movable joints, and movable joints.
Step-by-step explanation:
The functional classification of joints is based on the type and degree of movement they allow. There are three types of action/functional joints: immovable, partially movable, and movable joints. Immovable joints, also known as synarthroses, are joints that do not allow any movement. They are tightly fused together and provide stability and support. Examples of immovable joints include the sutures between the bones of the skull.
Partially movable joints, also known as amphiarthroses, allow limited movement. The bones in these joints are connected by fibrous or cartilaginous tissues. An example of a partially movable joint is the intervertebral discs between the vertebrae in the spine.
Movable joints, also known as diarthroses, allow a wide range of movement. These joints have a space between the bones called the synovial cavity, which is filled with synovial fluid. Examples of movable joints include the shoulder joint and the knee joint. In summary, the three types of action/functional joints are immovable joints (synarthroses), partially movable joints (amphiarthroses), and movable joints (diarthroses).