Description: This module begins with a review of embryologic breast development covering developmental variants and congenital anomalies and progresses to a discussion of the internal and external anatomy of the female breast tissues and surrounding structures, including veins, arteries, nerves, and the lymphatic system. Cases are presented to demonstrate the sonographic anatomy of the breast zones, layers, tissues, and glandular elements. The muscles of the chest wall are shown sonographically. In conclusion, the hormonal changes associated with adolescence, pregnancy, lactation, and menopause are depicted with case examples. Core Concepts: 60 min Focus Session: 45 min CME 1.25 SDMS CME