Final answer:
The syringe tip, needle hub, and inner plunger are critical sites that must be kept unobstructed from direct airflow to prevent contamination during pharmacy compounding.
Step-by-step explanation:
The tip of the syringe, needle hub, and inner plunger are critical sites that should not be blocked from direct airflow when compounding. These areas are critical because they are directly exposed to the sterile product and the environment; therefore, maintaining their sterility is essential to avoid contamination. In pharmacy compounding, particularly in aseptic compounding, it's vital to protect these critical sites to ensure that the preparations are safe for patient use.