The breast:

1. (a) is a tubulo-acinar type of modified apocrine sweat gland.

2. (b) has mammary glands which develop from the pectoral portion of the milk line.

3. (c) has lobes that are epidermal in origin.

4. (d) has lactiferous ductules, acinar ducts and acini that are lined by a single layer of cuboidal epithelial cells.

5. (e) has the terminal duct lobular unit (TDLU) which consists of 15–20 lobes drained by a single lactiferous duct.

The breast:

1. (a) lies entirely within the deep fascia of the chest wall.

2. (b) has the greatest proportion of fibroglandular tissue in the upper outer quadrant which gives rise to the axillary tail.

3. (c) has fibrous strands of deep fascia that pass through it towards the skin and nipple.

4. (d) has its main blood supply through the lateral thoracic and internal mammary arteries.

5. (e) has a venous drainage through the azygos system.

In the lymphatic drainage of the breast:

1. (a) The pectoralis major muscle is the reference for the surgical level of nodes.

2. (b) This includes intercostal and internal thoracic chains.

3. (c) Level 1 nodes are inferolateral to the pectoralis muscle.

4. (d) Level 2 nodes are superomedial to the pectoralis muscle.

5. (e) Excision of level 3 nodes requires radical surgery.

The breast ANSWERS

1. (a) True

2. (b) True – the primitive ectodermal milk line runs from the base of the forelimb to the region of the hindlimb.

3. (c) True

4. (d) True – the ducts are lined by columnar cells.

5. (e) False – 15 to 20 lobes drain by lactiferous ducts onto the nipple. The lobes are divided into lobules. A lobule consists of a group of acini supplied by one terminal duct – the terminal duct lobular unit.