Chapter 3 of PBOK goes into detail of the 42 management processes. Table 3-1 on page 42 is a great visual that shows the mapping of the 42 management processes into the 5 Project Management Process Groups (Initiating, Planning, Executing, Monitoring & Controlling, and Closing) and the nine Project Management Knowledge Areas (Project Integration Management, Project Scope Management, Project Time Management, Project Cost Management, Project Quality Management, Project Human Resource Management, Project Communications Management, Project Risk Management, and Project Procurement Management). Like @ks629 mentions that processes from any group may be used throughout the project life cycle. For medical devices another example would be regulatory where you would use all the process groups throughout the life cycle; selecting the regulatory route, plan communications as @krp67 mentions with FDA, plan risk management, perform quality assurance,and perform quality control etc.

When looking at Table 3 on page 42 it has the relationships between Process Groups and the relationships between Process Groups and external groups. What are the external groups involved and what are their roles/interactions with Process Groups?