What is the primary characteristic of synarthroses joints?

Synarthroses joints are defined by their primary characteristic of being immovable. These types of joints are designed for stability and support in the skeletal structure rather than for a range of motion. For instance, the sutures found in the skull are classic examples of synarthroses; they firmly connect the bones of the skull, allowing for no movement and providing protection to the brain. This immovable nature is critical in areas of the body where structural integrity is vital.

The other options refer to different types of joints that allow varying degrees of motion. Limited movability generally applies to amphiarthroses, which permit some movement but not as extensive as diarthroses, or fully movable joints. Thus, the key feature that distinguishes synarthroses from other classifications of joints is their complete lack of movement, solidifying their role in maintaining the strength and stability of anatomical structures.