Read from Dr. JPJ’s notes!

Location

  • Vertically
    • 2-6 ribs
    • in mid-clavicular line
  • Horizontally
    • lateral border of the sternum to the mid axillary line

Mammary bed:

  • Pectoralis major
  • Serratus anterior
  • Rectus abdominis

Retromammary space

  • Loose connective tissue
    • between base of gland and the fascia covering the muscles
  • Gives mobility

Axillary tail (of Spence)

  • Tail like projection
    • from the upper & outer quadrant of the gland entering the axilla

Nipple

  • cylindrical/conical projection
  • 4th intercostal space
    • in nulliparous females
  • pierces by 15-20 lactiferous ducts
  • contains
    • circular muscle fibres
      • erection
    • longitudinal muscle fibres
      • retraction
  • Rich nerve supply
    • sensory receptors for sucking

Areola

  • pigmented
  • pink in nullipara
  • irreversible darkening after 1st pregnancy
  • outer margin contains
    • modified sebaceous glands
    • Montgomery’s tubercles
      • enlargement of sebaceous glands
  • Devoid of hair & subcutaneous fats

Breast

MALE

  • have duct system, but do not have alveoli
  • some fibro-fatty tissues
  • breast tissue does not extend beyond margin of areola
  • richly drained by lymphatics
  • Gynecomastia common
    • Klinefelters (47XXY)
    • Endocrine disorders
    • decreased liver function
  • Carcinoma rare
    • but worse prognosis!

FEMALE

  • 3 major components:
    • Glandular tissue
      • tubulo-alveolar glands arranged in lobes
      • 15-20 pyramidal love
        • drained by single lactiferous duct
      • arranged radially
      • converge towards areola
      • each duct drains a segmental system of smaller ducts & lobules
      • each duct dilates towards the end to form the lactiferous sinus
        • reservoir for milk
      • have myoepithelial cells
        • smooth muscle
        • for secreting milk
    • Fibrous tissue
      • support the lobes
        • by suspensory ligaments of Cooper
      • form septa which anchor the parenchyma to the overlying skin & the underlying pectoral fascia
    • Fatty tissue
      • fills space
      • give rounded contour
      • beneath nipple & areola

Functions of breast

  • lactation
    • synthesis, secretion, ejection of milk
  • myoepithelial cells
  • resting & lactating (look for photo)
    • anatomy
    • histology

Embryology

  • develop from
    • ectoderm (all glands)
      • epithelial lining of ducts & alveoli
    • mesoderm (fibrous tissue, fats)
      • stroma
  • develop along milk line/ridges
  • Amastia: absense of breast
  • Polythelia
    • supernumerary nipples found irregularly over the breast and not along the milk ridges
    • thelia: nipple, poly: many
  • Polymastia
    • accessory breasts along the milk line

Changes of structure of breast with age

  • Up to prepuberty
    • have lactiferous ducts
    • no alveoli
  • Puberty
    • ducts undergo branching
      • form solid masses of cells: precursors of alveoli
  • Pregnancy
    • Alveoli secrete milk & enlarge
    • Colustrum: 1st mik (rich in Ig & cholesterol)
  • Lactation
    • Myoepethelial cells help in milk ejection
  • After lactation
    • shrinking of alveoli
    • return to resting condition

Arterial supply

  • Lateral mammary branches
    • from lateral thoracic artery of axillary artery
  • Superior thoracic artery
    • from axillary artery
  • Medial mammary branches
    • from perforating branches of the internal thoracic artery (2,3,4 spaces)
  • Lateral branches
    • of 2,3, 4 intercostal arteries

Venous drainage

  • Circular venosus
    • plexus below areola
    • drains into axillary, internal thoracic & intercostal veins
  • Communication with internal vertebral venous plexus (of Batson)
    • through intercostal & azygos veins
    • metastasis by retrograde venous flow to sagittal & transverse sinuses, clavicle, humerus & cervical vertebrae
    • no valves, can move in any way

Nerve supply

  • Anterior & lateral cutaneous branches
    • of 4th & 6th intercostal nerves
    • carry motor (skin) & sympathetic nerves (vasomotor)

Lymph node & drainage

  • Parenchyma (including nipple & areola)
    • drain into
      • axillary nodes (70%)
      • parasternal nodes
      • posterior intercostal nodes
    • deep lymphatics
  • Skin (excluding nipple & areola)
    • outer
      • axillary nodes
    • upper
      • supraclavicular nodes
    • inner
      • parasternal nodes
    • can spread to subdiaphragmatic nodes?
      • abdomen
    • can spread to ovary
      • Krukenberg’s tumour

Clinical anatomy

  • Witch’s milk
    • baby express milk
    • esposed to maternal hormone
    • not really milk
  • Breast abscess
    • improper hygiene during breastfeeding
  • Incision of lactiferous ducts
    • radial incision
  • Carcinoma
    • usually arises from epithelium of larger ducts
  • Benign fibrodenomas
    • usually arise from distal smaller ducts
  • Tumour
    • retraction of skin & fixation
    • retraction of nipple
    • Peau d’orange
      • pull Cooper’s ligament
        • skin pulled back
      • lymph duct blocked
        • lymph oedema
    • Diagnosis of breast cancer:
      • mammography
      • radical mastectomy
      • Breast self examination

2 COMMENTS

LEAVE A REPLY

Please enter your comment!
Please enter your name here