Breast

Question 1

What are the surface markings of the breast?

Answer 1

• Lateral border of sternum to AAL horizontally
• 2nd and 6th ICS vertically
• Medially follows 6th rib
• Superficial to pec major and serratus anterior

Question 2

What are the regions of the breast?

Answer 2

• Circular body, main region of the breast

- Axillary tail, process pointing superolaterally to axilla

Question 3

What are the three main anatomical features of the breast?

Answer 3

• Mammary glands: ducts and 15-20 secretory lobules, with alveoli drained by lactiferous duct
• all ducts converge at nipple
• alveoli produce milk in lobules, with each lobule draining to one lactiferous duct, with all of these converging to areola
• Fibrous stroma: condenses to form suspensory ligaments (of Cooper) - attach and secure breast to dermis and underlying pectoral fascia - separate the secretory lobules of the breast
• Pectoral fascia: base of the breast lies on the fascia - sheet of connective tissue associated with pec major; fibrous and strong layer with coopers ligaments attached

Question 4

What is the arterial vascular supply of the breast?

Answer 4

mammary branches of internal thoracic supply medial side of the breast and nipple/areola

intercostal arteries also supply some branching

lateral thoracic artery branches off the subclavian and supplies the lateral region of the breast

some supply from the thoraco-acromial and thoracodorsal arteries, and also branches from 2nd-4th ICS arteries

Question 5

What is the venous drainage of the breast?

Answer 5

draining to axillary and internal thoracic veins

Question 6

What is the innervation of the breast?

Answer 6

Innervation: branches of intercostal T2-T6, forming anterolateral and anteromedial branches as well as supraclavicular nerves to the upper and lateral parts of the breast

Nipple: lateral cutaneous branch of T4

Question 7

What is the lymphatic drainage of the breast?

Answer 7

• Axillary nodes: located in axilla and accept 75% of lymph
• Parasternal: located next to sternum 20%
• Posterior intercostal: 5% - where ribs articulate with vertebral bodies
• Skin: drains to axillary, inferior deep cervical and infraclavicular nodes
• Nipple and areola: drains to the subareolar lymphatic plexus