stability - the ability of a joint to resist displacement or dislocation; the strength of the bonds between the bones in a joint

mobility - the degree to which the bones are allowed to move before being restricted by surrounding tissues

flexibility - another term for mobility

DOF - the linear & angular directions of movement considered normal for a joint; general measure of mobility

ROM - the angle through which a bone moves about a joint from anatomical position to the extreme limit of a segment motion in a particular direction; a specific measure of joint mobility

hypermobile - describes a joint where ROM exceeds normal limits

hypomobile - describes a joint where ROM is less than what would normally be permitted

laxity – degree of instability in a joint – the ROM in those directions considered to be abnormal for the joint

luxation – complete distraction, usually transient

subluxation – a transient decrease in the normal area of contact between the articular surfaces in a synovial joint (partial distraction or separation)

dislocation – complete distraction that persists after the load causing it is removed