A newborn infant more than triples in height and increases in weight some 20-fold before reaching maturity. During the process, structures change in size and position. Some, which are critically important during fetal development, disappear. Most persist but grow at different rates at different ages. It is therefore not surprising that newborn anatomy differs from adults; some of these differences are particularly important for the pediatric surgeon (Table 3.1 and Figure 3.1). This chapter summarizes the applied anatomy of the newborn, emphasizing aspects that are clinically relevant and different to adults.