Kansetsu-waza (Joint locks) techniques includes joint lock techniques against many joints of the body, contemporary judo only involves kansetsu-waza against the elbow. And one can using legs, arms, and knees, to grasp the opponent's joint, and bend it in the reverse direction to lock the joint, thereby rendering him virtually helpless.
Here is the list of all Armbars and Arm Locks Technoques:
Other Joint Locks
Also check out Choking Techniques (Shimewaza) and Pinning Techniques (Osaewaza).
Or vist animation Throwing Techniques (Nagewaza) page.