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Anatomy of the thorax > Lymphatic Drainage of the breast > Flashcards

Lymphatic Drainage of the breast Flashcards

1
Q

What are the mammary glands

A

A modified (apocrine) sweat gland, and under hormonal influence to produce milk post-partum, it is made up of glandular tissue, fat and fibrous tissue
Found in the superficial fascia
Anterior to the pectoral muscles and the anterior thoracic wall

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2
Q

What do the breasts consist of

A

Mammary glands and associated skin and connective tissues.

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3
Q

Describe the embryology of the breast

A

The human breast develops under genetic and hormonal influence from skin precursor cells (ectoderm) during the fourth week of embryonic life.

Mammary ridges evolve in humans on the chest at the level of the fourth intercostal space and form a mammary bud by the fifth week of gestation

Background breast stroma (fat, ligaments, nerves, arteries, veins, and lymphatics) develops through- out gestation.

Beyond the twelfth week of gestation, the secondary buds continue to lengthen and branch, forming a complex network of radially arranged breast ducts that connect the developing (inverted) nipple with the growing mammary lobules

Failure of nipple eversion can occur, is often hereditary, and is usually secondary to fibrous tethering of the nipple within a hypoplastic ductal system.

After cessation of maternal hormone effects after birth, the breasts become quiescent until the onset of puberty.

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4
Q

What are the key events in the embryology of the breast

A

5th Week
Development
Mammary Bud

> 5th Week
Growth of Mammary
Bud into Chest

5-12th Week
Formation of
Secondary Buds

12th Week
Formation of
Mammary lobules

> 12th Week
Lengthening and branching
of ducts that connect the
developing (inverted) nipple

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5
Q

Describe nipple inversion

A

After gestation

Secondary to tissue attachment from back of nipple.

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6
Q

Describe the anatomy of the breast

A

Extends from the 2nd à 6th rib mid-clavicular.
o Nipple is located just inferior to 4th CC.

The breast lies on the deep fascia related to the pectoralis major muscle and other surrounding muscles.

The base extends transversely from the sternum and as far laterally as the midaxillary line

The breast parenchyma extends in the anterior axillary fold as the axillary tail of Spence

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7
Q

What are the areas of the breast

A

Body sternum

Axillary tail
Anterior axillary
Fold
Nipple
Areola
Inframammary
fold
Intramammary 
Cleft (cleavage)
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8
Q

Which part of the breast contains the greatest volume

A

The upper half of the breast esp the UOQ contains the the greastest volume of breast tissue compared to the remaining breast

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9
Q

What does the breast consist of

A

The gland is comprised of 15-20 ductal-lobular units (lactiferous ducts) each draining into a main duct

Fat lies interspersed between the ductal lobular units

Divided by fibrous septae that radiate from the centre outwards (suspensory ligaments of Cooper).

There is a complex network behind the nipple and between 4 and 18 milk ducts open on the summit of the nipple or on the areola.

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10
Q

What happens during suckling

A

§ The deeper lactiferous sinuses are squeezed during suckling.

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11
Q

Describe the suspensory ligaments of cooper

A

-Connective tissue strandsthat connect anterior and posterior fascial planes

-Supporting structure

-Provides shape and consistency of parenchyma

The fibrous septae that radiate from the centre support the breast.
o Known as the suspensory ligaments of Cooper.

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12
Q

Describe the blood supply to the breast

A

Laterally- vessels from the axillary artery- superior thoracic, thoraco-acromial, lateral thoracic and supcapsular arteries
Medially- branches from the internal thoracic artery
second to fourth intercostal arteries via branches that perforate the thoracic wall and overlying muscle.

The nipple-areola receives a branch from the internal thoracic artery in most cases.

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13
Q

Describe the blood supply to the skin of the breast

A

The skin is supplied by the subdermal plexus which communicates with the deep parenchymal vessels.

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14
Q

Describe venous drainage of the breast

A

3 principle groups of veins

Perforating branches of the internal mammary vein

Tributaries of the axillary vein

Perforating branches of the posterior intercostal veins

(these lie in direct continuity with the vertebral plexus of veins (Batson plexus) – important conduit for haematogenous dissemination of breast cancer to spine or pelvis

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15
Q

Describe the innervation of the breast

A

Mainly - anterolateral and anteromedial branches of thoracic intercostal nerves T3-T6. There is also innervation from the supraclavicular nerves to the upper and lateral parts of the breast.

The nipple - dominant supply from the lateral cutaneous branch of T4.

Principally through the lateral and anterior cutaneous branches of the 2nd through 6th intercostal nerves

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16
Q

Describe the lymphatic drainage of the breast

A

Approximately 75% is via lymphatic vessels that drain laterally and superiorly into axillary nodes (humeral, pectoral, subscapular, central and apical nodes)
Some drainage into , supraclavicular or deep cervical LNs
Medial quadrant – drains Internal Mammary LNs –
- Lower quadrant – drains inferior phrenic (abdominal) nodes

Most of the remaining drainage is into parasternal nodes deep to the anterior thoracic wall and is associated with the internal thoracic artery
Some drainage may occur in the lymphatic vessels that follow the lateral branches of posterior intercostal arteries and connect with intercostal nodes situated near the head and neck of ribs.

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17
Q

Describe the breast as a pyramid and highlight its boundaries

A

A pyramidal compartment that is tightly invested between the upper extremity and the thoracic wall – 4 boundaries

  • Medially: Serratus Anterior over 1st 4 ribs
    Laterally: Intertubercular groove of humerus & Biceps tendon, & Coracobrachialis
    Anteriorly: Pectoralis Major & Minor
  • Posteriorly: Teres Major, Subscapularis + tendon Latissimus Dorsi

Lymph nodes found on each corner of the breast

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18
Q

Where are Rotter’s lymph nodes found

A

Between pec major and pec minor

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19
Q

Describe the lymphatics of the breast

A

§ Lymphatics help mediate the spread of cancer.
§ Drainage from the breast is predominantly towards the axilla.
§ Removal of too many lymph nodes in the axilla result in oedema in the associated arm.
o This means usually just the sentinel node is removed (the closest node).
o Located by injecting a small volume of dye which the closest node will take up.
o This node is then removed to decrease the chance of metastasis

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20
Q

Describe the lymph glands of the breast

A

§ From the sub-mammary and sub-areolar plexuses, lymph from most of the breast drains to the:
o Pectoral group of axillary nodes (HENCE WHY MOST METASTISIS IS TO HERE).
§ There is drainage to adjacent parts of the breast too:
o Infra-clavicular group.
o Parasternal nodes.
o Mediastinal nodes.
o To the opposite breast.

21
Q

Describe how we determine the severity of the breast tumour

A

Has the tumour grown within the breast tissue or spread to the lymph nodes
How big is it
Has the cancer spread to other organs (metastasis)
What does the tumour look like?
What receptors does it have?

22
Q

Describe the lymph capillaries

A

Lymph capillaries make a richly anastomosing network within the breast and overlying skin.

The superficial parts of the breast drain to the sub-areolar plexus and the deep parts to the submammary plexus that lies in the deep fascia overlying pectoralis major and serratus anterior.

23
Q

What are the dangers of axillary clearance surgery

A

Long thoracic nerves and thoracodorsal nerves are the motor nerves in the axilla- supply latissimus dorsi- may not be able to lift arm.

24
Q

Describe sentinel node biopsy

A

Found in the axilla- can be sampled by sentinel node biopsy
Where the cancer may spread to first
Coloured dye or radioactive tracer is injected into breast tissue surrounding the tumour
The injected substance then drains into the sentinel nodes- identifying them for surgical removal
Surgically removed and examined for cancer cells

25
Q

What is meant by anatomical dissection

A

Removal of an anatomical space

26
Q

What do we use to visualise the lymph nodes

A

Gamma counter - Tech99- reducing morbidity of the operation

27
Q

Describe breast cancer related lymph

A

Long term, progressive condition, poorly understood & under reported
Negatively impacts overall QoL (emotional distress, anxiety and disturbance of body image)
Risk factors:
treatment factors: axillary surgery, LRRT, systemic taxane CT
patient factors - ↑ BMI

Fiscal burden in LE patients
- $14,877 - $23,167 over 2 years

28
Q

What is meant by lymphoedema

A

Abnormal, generalized or regional accumulation of protein rich interstitial fluid

Oedema formation and change in tissue architecture

29
Q

What does lymphoedema result in

A 
REDUCTION IN
LYMPHATIC 
TRANSPORT
CAPACITY 
Increased lymphatic load
Also a higher risk of infection
30
Q

Describe the cumulative incidence of lymphoedema

A

90% patients will develop LE in the first 24-36 months

31
Q

What do we know about lymphoedema

A

Not just a blockage – “heart attack” of the lymphatic system
Long term, progressive, poorly understood & under reported
Negatively impacts overall QoL
Fat accumulation and scarring
Not all lymphoedema behaves the same way

32
Q

What else can be avoided to reduce the risk of L.E

A

Venipuncture
Injections
BP measurements and
The use of compression sleeve for air travel

33
Q

Describe the evidence for other risk factors potentially related to L.E

A
  1. Flying :It has been postulated that low cabin pressure and reduced activity may either initiate lymphedema in ‘at-risk’ patients or exacerbate the condition
    Air travel has no effect on lymphoedema - Retrospective and Prospective studies have refuted this*
  2. Blood draws andninjection - Evidence is poor quality and conflicting
    Lymphoedematous limbs are prone to cellulitis after minor trauma; BUT sterile puncture of the skin does not increase infection
  3. Hypothesis: increased pressure in the limb results in increased lymph production, fibrosis and stenosis of the lymphatic vessels
    No evidence to suggest that BP readings taken from an ‘at-risk’ arm increases the risk of lymphedema
  4. Role of exercise is controversial
    Historically: avoid lifting children and heavy objects (bags)
    RCTs – aerobic exercise: including yoga, nordic walking & arm cycling -SAFE
    NLN emphasizes importance of exercise in both at-risk and affected patients
34
Q

What are the different ways for diagnosing L.E

A

Self report
Water displacement therapy (strict protocol, unhygienic)
Circumferential type measurement (accessible but cumbersome and requires a lot of training to achieve reproducible results)
Perometry (expensive)
Bioimpedence spectroscopy (limited to unilateral patients, no role in established fatty lymphoedema)

35
Q

List the strategies to reduce lymphoedema

A

Less axillary surgery

Axillary reverse mapping (ARM)

LYMPHA

36
Q

Describe Axillary reverse mapping

A

Aims to identify and preserve nodes and/or lymphatics draining from the arm during ALND, thereby minimizing arm lymphedema

Reverse mapping – blue dye, radioisotope or ICG

37
Q

How do we determine the arm nodes

A

ISOTOPE / ICG / DYE MAPPING

Injection into the wrist of wrist spaces of the ipsilateral arm

Site massaged and the arm elevated for 5 minutes to enhance arm lymphatic drainage

ARM localization in 90-93%

38
Q

What may be the issue with Axillary reverse mapping

A

If there is crossover (concordance- arm lymphatic is metastatic) either:

Reanastomose the afferent and efferent lymphatics (not lumen to lumen)

LVA (LYMPHA)

39
Q

What is LYMPHA

A

(Lymphatic Microsurgical Preventative Healing Approach
Multiple Lymphatic-venous anastomoses (LVA) between arm lymphatics and collateral branches of axillary vein at the same time as Axillary dissection

40
Q

What are the benefits of LYMPHA

A

Short operative time
Possibly to prevent secondary lymphoedema
Reduction in early lymphatic complications
Improvement in QoL
Reduction In health costs

41
Q

Describe the congenital abnormalities of the breast

A

Underdevelopment or absence of one breast (may coexist with muscle/ribcage anomaly) – *Poland syndrome

Accessory nipples (polythelia) absent nipples (athelia)

Accessory breast tissue

Tubular breast defomity

42
Q

Describe the axillary tail of the breast

A

It is important for clinicians to remember when evaluating the breast for pathology that the upper lateral region can project around the lateral margin of the pectoralis major muscle and into the axilla.
This axillar process (axillary tail) may perforate deep tissue and extend as far superiorly as the apex of the axilla

43
Q

What can subcutaneous lymphatic obstruction and tumour growth result in

A

Pulls on connective tissue ligaments in the breast, resulting in the appearance of an orange peel texture (peau d’orange) on the surface of the breast. Further subcutaneous spread can induce a rare manifestation of breast cancer that produces a hard, woody texture on the skin (cancer en cuirasse).

44
Q

What are the potential complications of a mastectomy

A

Surgical removal of breast
Involves excision of the breast tissue to the pec major muscle and fascia
Within the axilla, the breast tissue must be removed from the medial axillary wall
Closely applied to the medial axillary wall is the long thoracic nerve
Damage to this nerve can result in paralysis of serratus anterior muscle, producing the characteristic winged scapula
It is also possible to damage the nerve to the L.dorsi and this may affect extension, medial rotation, and adduction of the humerus.

45
Q

Describe the breast in men

A

Rudimentary and consists only of small, often composed of cords of cells, that normally do not extend beyond the areola.
Breast cancer can occur in men and also in accessory nipples.

46
Q

What is the retromammary space

A

A layer of loose connective tissue separates the breast from the deep fascia and provides some degree of movement over underlying structures.

47
Q

What does carcinoma of the breast cause

A

Tension on the ligaments- causing pitting of the skin.

48
Q

What are the dominant components of the breast

A

Non lactating women= fat

Lactating women = glandular tissue

49
Q

What is meant by the ligaments of cooper.

A

The breast is divided into fibrous septae that radiate outward (the ligaments) and sometimes the TETHERING or drawing in of the skin occurs due to the suspensory ligaments of Cooper becoming involved in the tumour process.

Anatomy of the thorax (11 decks)

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