Anatomy of the Breast

Introduction

• The breast is a modified sweat gland present in both sexes.
• It develops in females after puberty and secretes milk.
• It is an accessory organ of the female reproductive system.

Clinical Anatomy

• Location: The breast is situated on the superficial fascia of the pectoral region and a small portion (axillary tail) pierces the deep fascia to lie in the axilla.
• Shape: in young adult females, the breast is spherical but later becomes pendulous.
• Extent: Vertically, it extends from the 2nd to 6th rib, horizontally at the level of the 4th costal cartilage from the lateral sternal border to midaxillary line. The superior portion laterally prolongs into the deep fascia as the foramen of Langer, lying at the level of the 3rd rib and later known as the axillary tail of Spence. (This area where the breast extends laterally into the axilla).
• Component Parts include Skin, Parenchyma, and Stroma.

Breast Structure

• Skin: The breast is enclosed by skin. This section includes the nipple as a conical projection located at the 4th intercostal space; containing 15-20 lactiferous ducts.
• Parenchyma: The glandular tissue of the breast that produces milk. It consists of 15-20 lobes, each with a cluster of alveoli and drained by lactiferous ducts. These ducts dilate into lactiferous sinus beneath the areola. These lactiferous ducts converge towards the nipple radiating like spokes.
• Stroma: The supporting framework of the breast; made up of fibrous stroma which divides into septa, known as Cooper's ligaments. Connects the skin to pectoral fascia. The fatty stroma forms the bulk of the breast.

Deep Relation

• The breast is related to the retromammary space of loose areolar tissue.
• Further associated with deep pectoral fascia, pectoral major, serratus anterior and the external oblique abdominis.

Areola

• The areola is a pigmented area at the base of the nipple, rich in modified sebaceous glands (Montgomery tubercles).
• During pregnancy and lactation, the areola becomes enlarged, forming tubercles with oil-secreting Montgomery glands that lubricate the nipple and areola. It's mostly fat-free.

Lymphatic Drainage of the Breast

• The lymphatic drainage is crucial in disease spread.
• The system divides into superficial and deep components that communicate freely.
• Superficial nodes drain the skin of the breast, excluding the areola and nipples.
• Deeper nodes drain the breast parenchyma, nipple, and areola.
• Drainage follows patterns including lateral upper and lower quadrants to axillary and infraclavicular nodes.
• Medial parts drain via intercostal spaces to parasternal nodes with possible communication through supraclavicular nodes.

Blood Supply

• The blood supply of the breast includes the internal thoracic perforating vessels extending to 2nd-6th intercostal spaces.
• Other critical arteries are the lateral thoracic, superior thoracic, and acromio-thoracic branches.

Clinical Anatomy (Tumours)

• Breast is a common site for tumours, benign or malignant.
• Cancerous cells in ligaments cause breast fixation, skin retraction, and puckering.
• Malignant breast tumours, known as breast cancer, may affect one or both sides.
• Surgical procedures like a radical mastectomy might be required.
• Common characteristics of breast cancer (malignant) include skin dimpling/puckering and an orange peel appearance.