Thorax 4 - Breast + Lymphatic Drainage

Question 1

Describe lactation

Answer 1

Alveoli (cuboidal cells) produce milk
Carried to areola in lactiferous ducts
Myoepthelial cells in alveoli contract in response to oxytocin (posterior pituitary) = pushes milk along ducts

Question 2

Breast size depends on

Answer 2

Fat

younger women have denser less fatty breast than post-menopausal

Question 3

What separates breast lobules

Answer 3

Suspensory ligaments w are continuous w dermis of skin - maintain breast shape

Question 4

Breast Relations

Answer 4

Base -extends from Rib2-6 MCL
Overlies pec major and laterally extends to lie on serratus anterior + external oblique
Axillary tail extends into medial wall of axilla

Question 5

Axillaa boundaries

Answer 5

Anterior - pec major
Medial - serratus anterior
Posterior: lat dorsi, subscapularis, teres major
lateral: intertubercular sulcus

Question 6

Breast Blood supply (5)

Answer 6

Internal thoracic (dominant) - nipple areola gets a branch
Lateral thoracic
Thoraco-acromial
Dorsal artery
IC artery

Question 7

Lymphatics of breast

Answer 7

75% drains to pectoral group of axillary nodes w also gets drainage from subaerolar and submammary plexus.

Infraclavicular, abdominal lymphatics (inferiorly) and parasternal (medially) nodes get some drainage

Question 8

Lymphatic tissues and organs contains:

Answer 8

tonsils, spleen, thymus, adenoids

Question 9

Lymphatic system function

Answer 9

Drain excess EC fluid, drains everything except brain
Imm function
Nodes filter lymph bfore returns to circulatory system

Question 10

Lymph nodes

Answer 10

palpable in armpit, groin and neck
Lymphadenopathy indicative of infection
Nodes are small and found along lymph vessels

Question 11

Lymph

Answer 11

Clear and odourless
Lymph from SI is opaque and milky bc of fats abdorbed
Intestinal lymph = chyle.

Question 12

Lymph movement

Answer 12

Main lymphatic vessel = thoracic duct

Start L2 on RHS at cisterna chyli,
Goes through diaphragm at T10, posterior to oesophagus
Ascends on R of midline between aorta and azygois vein
Crosses LHS at T5 and ascends
Travels posterior to great veins, bends anteriorly to drain into jugular angle.
thoracic duct drains into junction of L subclavian + L jugular vein merge to form L brachiocephalic vein

Other than R upper quadrant, drains into R subclavian vein, then drains into thoracic duct and into L subclavian

Question 13

Thoracic Wall lymphatics

Answer 13

• Parasternal nodes (anterior part of thoracic wall)
• Upper part of intercostal lymphatics drains into brachiocephalic trunk
• Cisterna chyli are lymphatics that drain abdomen and lower limbs. Diaphragmatic lymph nodes drain into aortic.lumbar area of thoracic duct
• Superficial nodes drain via axillary/parasternal nodes

Question 14

Lung Lymphatics

Answer 14

Tracjea-bronchial lymph nodes, largest lymph node collection sit under tracheal bifurcation.
They unit vessels from parasternal and briocephalic nodes forming L + R bronchiomediastinal trunks

Question 15

Heart lymphatics

Answer 15

follow coronary arteries, drain into brachiocephalic + tracheobronchial vessels

Question 16

Posterior Mediastinum lymphatics

Answer 16

lymph from oesophagus, diaphragm, liver and pericardium drain into thoracic duct and posterior mediastinal nodes