You can navigate by using the keyboard instead of the mouse. Several keyboard access features are available on Mac OS; see the documentation for your operating system for details. On Windows, some of the keyboard shortcuts used to navigate in Reader may differ from those used in other Windows applications.
When you open Reader within a web browser, keyboard commands are mapped to the web browser first. Consequently, some keyboard shortcuts may not be available for Reader or may be available only after you shift the focus to the PDF.
For information on accessibility features for navigating Reader and PDF documents with the keyboard, visit the accessibility page of the Adobe website.