Typical synovial joint : easy discussion about features

Synovial joint:

 is the most common joint in the body 

Minimum to Wide range of movement is one of the important features of synovial joint

why synovial joint moves but other joints (like fibrous and cartilaginous) movement are restricted ?

Joint means articulation or junction between two or more bone,
in synovial joint bones are separated by a joint cavity 
This joint cavity are responsible for wide range of movement 
So joint cavity is the unique character of a synovial joint