A Structured activity node is an executable activity node that may have an expansion into subordinate nodes as an activity group. The subordinate nodes must belong to only one structured activity node, although they may be nested.

Specify the Structured Activity Node element in the Structured Activity Node Specification window.  

To open the Structured Activity Node dialog box, in the Activity diagram draw a Structured Activity Node element. From its shortcut menu, choose Specification.   

A variable defined in the scope of the structured activity node. It has no value and may not be accessed outside the node.