Chapter 17: Breast
Which of the following statements about normal breast anatomy is true?
A. The breast typically contains 10 lobes.
B. Cooper ligaments are only found in the upper quadrants of the breast.
C. The upper inner quadrant of the breast contains the most breast tissue.
D. The tail of Spence extends across the anterior axillary fold.
The breast is composed of 15 to 20 lobes, which are each composed of several lobules. Fibrous bands of connective tissue travel through the breast (Cooper suspensory ligaments), insert perpendicularly into the dermis, and provide structural support. The mature female breast extends from the level of the second or third rib to the inframammary fold at the sixth or seventh rib. It extends transversely from the lateral border of the sternum to the anterior axillary line. The deep or posterior surface of the breast rests on the fascia of the pectoralis major, serratus anterior, and external oblique abdominal muscles, and the upper extent of the rectus sheath. The retromammary bursa may be identified on the posterior aspect of the breast between the investing fascia of the breast and the fascia of the pectoralis major muscles. The axillary tail of Spence extends laterally across the anterior axillary fold. (See Schwartz 10th ed., p. 500.)
Which of the following changes in the breast is NOT associated with pregnancy?
A. Accumulation of lymphocytes, plasma cells, and eosinophils within the breast.
B. Enlargement of breast alveoli.
D. Accumulation of secretory products in minor duct lumina.
With pregnancy, the breast undergoes proliferative and developmental maturation. As the breast enlarges in response to hormonal stimulation, lymphocytes, plasma cells, and eosinophils accumulate within the connective tissues. The minor ducts branch and alveoli develop. Development of the alveoli is asymmetric, and variations in the degree of development may occur within a single lobule. With parturition, enlargement of the breasts occurs via hypertrophy of alveolar epithelium and accumulation of secretory products in the lumina of the minor ducts. Alveolar epithelium contains abundant endoplasmic reticulum, large mitochondria, Golgi complexes, and dense lysosomes. Two distinct substances are produced by the alveolar epithelium: (1) the protein component of milk, which is synthesized in the endoplasmic reticulum (merocrine secretion); and (2) the lipid component of milk (apocrine secretion), which forms as free lipid droplets in the cytoplasm. Milk released in the first few days after parturition is called colostrum and has low lipid content but ...