Determine client area available to MDI child forms

I need to know the bounds of the client area of an MDI parent form that is available to MDI child forms. In other words, the area of the MDI parent's ClientRectangle that does not include docked controls. What I'm doing is automatically setting the bounds of MDI child forms so that they fit within the area of the MDI parent that is available to MDI child forms. The only two properties that I know of are ClientRectangle and ClientSize, both of which seem to include the region contained by docked controls

Thank you very much for any help
Lance