Study Notes on Breast Anatomy and Mammography

Anatomy of the Breast

  • Acini (Alveoli): Functional units in the breast that produce milk.

  • Parenchyma: Glandular tissue of the breast, which is involved in milk production.

  • Lactiferous Ducts: Tubes that carry milk from the lobules to the nipple.

  • Ampulla (Lactiferous Sinus): The pouch-like section of the lactiferous duct where milk accumulates before being ejected from the nipple.

  • Mammary Fat: Adipose tissue surrounding the mammary glands, providing cushioning and support.

  • Montgomery's Tubercles: Small raised glands on the areola, which secrete lubricating fluid.

  • Areola: The pigmented area surrounding the nipple, which contains Montgomery's tubercles.

  • Chest Muscles: Pectoralis major and minor, which provide structural support.

  • Axillary Lymph Nodes: Important for drainage of lymphatic fluid from the breast.

  • Fatty and Fibrous Tissue: Create the breast structure along with connective tissue.

Examination Content Specifications for Mammography

  • Purpose: To assess knowledge and skills for mammographers at entry-level.

  • Process: Involves a practice analysis survey of mammographers to determine necessary tasks.

  • Content Specification: Each category is linked to the Task Inventory for Mammography, detailing essential knowledge areas.

Major Content Categories and Subcategories

  1. Patient Care

    • Patient Interactions and Management: 14 questions

  2. Image Production

    • Image Acquisition and Quality Assurance: 33 questions

  3. Anatomy, Physiology and Pathology

    • 26 questions

  4. Imaging Procedures: 42 questions

Detailed Breakdown of Content Areas

1. Anatomy, Physiology, and Pathology

  • Localization Terminology

    • Clock position

    • Quadrants

    • Triangulation

  • External Anatomy

    • Breast margins

    • Nipple

    • Areola (includes Morgagni tubercles and Montgomery glands)

    • Angle of the pectoral muscle

    • Skin: sebaceous glands, sweat glands, hair follicles

    • Axillary tail

    • Inframammary fold

  • Internal Anatomy

    • Fascial layers

    • Retromammary space

    • Fibrous tissues

    • Glandular tissues:

      • Lobules

      • Terminal ductal lobular unit (TDLU)

      • Extralobular terminal duct

      • Intralobular terminal duct

      • Acinus (ductal sinus)

    • Adipose tissues

    • Cooper ligaments

    • Pectoral muscle

    • Vascular system

    • Lymphatic system

2. Cytology

  • Epithelial cells

  • Myoepithelial cells

  • Basement membrane

3. Pathology

  • Mammographic appearance and reporting terminology (BI-RADS)

    • Architectural distortion (e.g., asymmetry, focal asymmetry)

    • Characteristics of masses:

    • Shape (e.g., round, irregular)

    • Margin (e.g., circumscribed, indistinct, spiculated)

    • Density

    • Characteristics of calcifications:

    • Benign (e.g., skin, vascular)

    • Suspicious morphology (e.g., amorphous)

    • BI-RADS categories:

    • Mammographic assessment

    • Breast density (e.g., entirely fatty, heterogeneously dense)

    • Recommendations

    • Benign Pathology

    • Cysts

    • Galactocele

    • Fibroadenoma

    • Lipoma

    • High Risk Pathology

    • Lobular carcinoma in situ (LCIS)

    • Atypical ductal hyperplasia (ADH)

    • Malignant Pathology

    • Ductal carcinoma in situ (DCIS)

    • Invasive ductal carcinoma (IDC)

    • Inflammatory carcinoma

Overview of Breast Development

  • Milk-producing Organs: Structurally modified sweat glands and accessory glands of the female reproductive system.

  • Breast Development Timeline: Begins at 4th week of gestation.

  • Milk Line: A ridge extending from the axilla to the groin; accessory nipples (polythelia) and breast tissue can develop along this line.

Breast Location and Margin

  • Vertical Extent: From the 2nd to the 6th rib.

  • Horizontal Extent: From medial sternum to the mid-axillary line.

External Breast Anatomy

  • Components: Nipple, Areola, Montgomery Glands, Axillary Tail, Inframammary Fold, Skin (includes sebaceous glands and hair follicles).

Surface Anatomy

  1. Skin: Thickest at base, thinner towards the nipple.

  2. Nipple and Areola:

    • Nipple: Center point, with 15-20 orifices.

    • Areola: Circular area with Montgomery’s glands that secrete lubricating fluid.

Pectoralis Major Muscle

  • Anatomy: A thick, fan-shaped muscle located on the anterior side of the chest, lying posterior to the breast, originating from medial clavicle and lateral sternum to insert in the bicipital groove of the humerus.

  • Function: Acts as a radiographic landmark.

Lymphatic and Vascular Systems

  • Lymphatic Drainage: Majority drains to axillary nodes (75%), with a small percentage to internal mammary lymph nodes and parasternal nodes.

  • Vascular Supply: Mediated mainly through the axillary artery and internal thoracic artery, with specific branching to provide adequate blood to breast tissues.

Factors Influencing Breast Composition

  • Changes occur with age, hormonal fluctuations, pregnancy, lactation, and weight fluctuations, impacting the balance of glandular versus fatty tissues.

Hormonal Effects on the Breast

  • Major hormones include estrogen, progesterone, and prolactin that influence breast growth, development, and reproductive functions.

Male Breast Characteristics

  • The adult male breast is similar to a preadolescent girl's, with some small branching ducts. Enlargement (gynecomastia) can occur due to various factors but does not usually increase cancer risk.

Breast Cancer in Males

  • Similar signs and symptoms as in women; influenced by risk factors such as age, genetic predisposition, and hormonal levels.

Breast Augmentation and Reduction

  • Uses: For aesthetic enhancement or after mastectomy.

  • Impacts: Affect physical examination and potentially mammography detection.

Final Notes

  • Understanding the anatomy, pathology, and hormonal influences of both female and male breasts is crucial for effective diagnosis, management, and treatment of breast-related conditions.