Ybarra v. Spangard[1] was a leading case in California discussing the exclusive control element of res ipsa loquitur.

The contrary position would bar the application of res ipsa loquitur when there is no showing that the cause of the injury was the act of any particular defendant or instrumentality.

Joseph Ybarra consulted defendant Dr. Tilley, who diagnosed appendicitis and made preparations for surgery.

Every defendant who had control over the plaintiff's body, for any period, was bound to exercise ordinary care to see that no unnecessary harm came to him, and all would be liable for failure.

The injury was distinctly a part of his body not subject for treatment or even within the area covered by the operation.