The contemporary practice of breast surgery requires an in-depth understanding of breast anatomy and imaging. Ultrasound of the breast has emerged over the past decade as an essential component of the evaluation of patients with breast disease and as an important tool in the operating room (OR).
Surgeons are natural imagers since they are use to thinking 3-dimensionally. Once they understand how ultrasound machines create images, what the images mean, and how the images correlate with benign and malignant breast conditions, they become "sonographic clinicians." Surgeons synthesize the patient's history with their physical, mammographic, ultrasound, and magnetic resonance imaging (MRI) findings into a clearer understanding of the probable diagnosis and a future course of action. In the OR, ultrasound is an important tool to facilitate wire-localization excisional biopsies or partial mastectomies. Ultrasound can be used to localize nonpalpable benign or malignant lesions in the OR or map the location of a cancer prior to starting a mastectomy.
This chapter offers an introduction to understanding ultrasound anatomy of the breast. The chapter also includes a discussion on how to characterize the sonographic appearances of benign and malignant breast lesions as well as an atlas of common benign and malignant lesions of the breast.
There are literally thousands of drawings of the breast, its blood supply, lymphatic drainage, and regional nerves that can be found in anatomy books and textbooks on breast disease. The breast is composed of 15 to 20 lobes in most women. Within each lobe are numerous lobules and small ducts that join to form larger ducts, which then progress to form a single major lobar duct. The major lobar ducts come together beneath the nipple and widen as the lactiferous sinus (Figs. 30-1 and 30-2).
There are 3 zones within the breast. The premammary (PM) or subcutaneous fat zone contains Cooper ligaments (CL), and in some cases, a small number of peripheral ducts and lobules. The mammary zone (MZ) contains all of the central ducts and most of the peripheral ducts and lobules. The retromammary zone (RM) is the deepest of the 3 zones and contains only fat and ligaments. The anterior mammary fascia (AMF) and the retromammary fascia (RMF) encase the mammary zone. The lactiferous sinus (LS) is the dilated end of a main lobar duct. (Redrawn with permission from Stavros AT. Breast Ultrasound. Philadelphia, PA: Lippincott Williams, & Wilkins; 2004.)
Cross-sectional anatomy of the breast showing important landmarks. (Reproduced with permission from Harness JK, Wisher DB, eds. Ultrasound in Surgical Practice—Basic Principles and Clinical Applications. New York, NY: Wiley-Liss; 2001:159-236.)
In general, the central lobar ducts course away from the nipple in a radial pattern (Fig. 30-3). However, these ducts may be tortuous. Lobes vary in size ...