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Questions and Answers
Which component is NOT part of the breast structure?
Which component is NOT part of the breast structure?
What primarily supplies blood to the breast tissue?
What primarily supplies blood to the breast tissue?
Which of the following is a function of lymphatics in the breast?
Which of the following is a function of lymphatics in the breast?
The breast is primarily composed of which types of tissues?
The breast is primarily composed of which types of tissues?
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Which statement about breast lymphatics is correct?
Which statement about breast lymphatics is correct?
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Which lymph nodes receive drainage from the anterolateral aspect of the abdominal wall superior to the level of the umbilicus?
Which lymph nodes receive drainage from the anterolateral aspect of the abdominal wall superior to the level of the umbilicus?
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How many nodes are typically found in the Posterior or Subscapular group?
How many nodes are typically found in the Posterior or Subscapular group?
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What percentage of lymph from the breast travels to axillary nodes?
What percentage of lymph from the breast travels to axillary nodes?
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Which pathway is responsible for draining lymph from all quadrants of the breast?
Which pathway is responsible for draining lymph from all quadrants of the breast?
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Which lymph node group lies at the base of the axilla?
Which lymph node group lies at the base of the axilla?
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Which lymph nodes receive lymph from the upper inner quadrant of the breast?
Which lymph nodes receive lymph from the upper inner quadrant of the breast?
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Which type of breast node primarily receives lymphatic drainage from the upper outer quadrant?
Which type of breast node primarily receives lymphatic drainage from the upper outer quadrant?
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Identify the pathway that drains lymph from the breast through intramammary nodes and channels.
Identify the pathway that drains lymph from the breast through intramammary nodes and channels.
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What is the primary drainage area for the axillary lymph nodes?
What is the primary drainage area for the axillary lymph nodes?
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Which type of lymph nodes are primarily responsible for draining the inner quadrants of the breast?
Which type of lymph nodes are primarily responsible for draining the inner quadrants of the breast?
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Where are the supraclavicular lymph nodes located?
Where are the supraclavicular lymph nodes located?
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How many axillary lymph node groups are typically identified?
How many axillary lymph node groups are typically identified?
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The infraclavicular or deltopectoral lymph nodes primarily drain which part of the body?
The infraclavicular or deltopectoral lymph nodes primarily drain which part of the body?
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What is the significance of the vertebral venous plexus in cancer spread?
What is the significance of the vertebral venous plexus in cancer spread?
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Which lymph nodes are considered the final common pathway of the lymphatic system?
Which lymph nodes are considered the final common pathway of the lymphatic system?
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Which axillary lymph node group is located closest to the anterior axillary fold?
Which axillary lymph node group is located closest to the anterior axillary fold?
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Which structure serves as the primary site for milk production in the breast?
Which structure serves as the primary site for milk production in the breast?
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What is the axillary tail of Spence?
What is the axillary tail of Spence?
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What happens to the breast stroma during breast cancer?
What happens to the breast stroma during breast cancer?
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Which blood vessels primarily supply the medial aspect of the breast?
Which blood vessels primarily supply the medial aspect of the breast?
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What occurs during the involution of the breast after lactation?
What occurs during the involution of the breast after lactation?
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Which of the following best describes the nipple?
Which of the following best describes the nipple?
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Where is the majority of breast cancer found?
Where is the majority of breast cancer found?
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What initiates development of breast tissue in the human body?
What initiates development of breast tissue in the human body?
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What type of tissue mainly comprises the resting (non-lactating) breast?
What type of tissue mainly comprises the resting (non-lactating) breast?
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What component surrounds the lactiferous duct and allows movement on the deep pectoral fascia?
What component surrounds the lactiferous duct and allows movement on the deep pectoral fascia?
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Which anatomical structure is rudimentary in males?
Which anatomical structure is rudimentary in males?
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What degenerative change occurs in the breast after menopause?
What degenerative change occurs in the breast after menopause?
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Which modified gland produces lubrication for the nipple?
Which modified gland produces lubrication for the nipple?
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What is the primary function of lactiferous sinuses?
What is the primary function of lactiferous sinuses?
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Study Notes
Breast Structure
- The breast is primarily composed of fibrous and fatty tissue, with glandular tissue being sparse in the non-lactating state.
- The breast extends vertically from the second to sixth rib and horizontally from the lateral sternal border to the mid-axillary line.
- The majority of breast cancers develop in the upper outer quadrant.
- The axillary tail of Spence is a normal extension of breast tissue into the axilla.
Breast Position and Extent
- The breast is located in the superficial fascia of the pectoral region.
- Modified sweat glands (apocrine) are present in both sexes, but are rudimentary in males.
- Two-thirds of the breast overlies the pectoralis major muscle, and one-third overlies the serratus anterior muscle.
- A loose connective tissue plane, the retromammary space, is located between the breast and deep pectoral fascia, allowing for movement.
Breast Structure
- The parenchyma of the breast consists of 15-20 lobes of glandular tissue separated by connective tissue.
- Each lobe contains lobules, which in turn consist of acini (“bulbs”), responsible for milk production.
- Lactiferous ducts drain each lobe and converge to empty into the nipple.
- The lactiferous ducts widen into lactiferous sinuses before opening onto the surface.
- The skin surrounding the nipple is the areola, containing modified sebaceous glands (Montgomery’s tubercles) that lubricate the nipple during breastfeeding.
- The nipple and areola complex form the nipple-areola complex (NAC).
- The fibrous stroma of the breast, or suspensory ligaments of Cooper, divide the parenchyma into 15-20 segments, anchoring the skin to the deep fascia, and providing structural support.
Breast Development
- Breast development begins as early as the fourth week of gestation from a thickened mammary ridge (milk line).
- Milk line ectoderm forms a line from the axilla to the inguinal region, on which nipples or additional glands may appear.
- Lobule formation takes place after puberty, solely in the female breast.
Lactation
- The resting breast is mostly fibrous and fatty tissue.
- During pregnancy, alveoli bud from smaller ducts, leading to significant breast enlargement.
- Perforating arteries increase in size during pregnancy and lactation to provide sufficient blood supply to mammary glands.
- Secretory tissue involutes when lactation ceases.
- Atrophy of the lobes and ducts is progressive after menopause.
Male Breast
- Male breasts resemble rudimentary female breasts, with no lobules or alveoli.
- The nipple and areola overlie the fourth intercostal space.
- Breast cancer is rare in males.
Arterial Supply of the Breast
- Most breast arteries supply the anterior surface, while the posterior surface is relatively avascular.
- The major arteries supplying the breast include the internal thoracic artery, lateral thoracic artery, thoracoacromial artery, and posterior intercostal arteries.
- Medial aspect is supplied by internal thoracic artery, lateral aspect by lateral thoracic artery, and thoracoacromial artery, and the posterior aspect by posterior intercostal arteries
Venous Drainage of the Breast
- Most of the breast drains into the axillary vein, specifically via the lateral thoracic vein.
- Additional veins involved include the internal thoracic vein and posterior intercostal veins, which communicate with the vertebral venous plexus (allowing for potential cancer spread).
Lymphatics of the Breast
- The largest group of lymph nodes draining the breast is the axillary lymph nodes, which drain approximately 75% of the breast.
- Parasternal (internal mammary) nodes drain the inner quadrants.
- Infraclavicular or deltopectoral nodes drain the anterolateral aspect of the upper limb.
- Supraclavicular nodes serve as the final common pathway for lymphatic drainage to the central venous system.
- Other important lymphatic groups include the lateral, pectoral, and subscapular nodes.
- The drainage areas encompass the upper limb, breast, and trunk above the umbilicus.
- Individual axillary lymph nodes are categorized into five groups, including anterior/pectoral, posterior/subscapular, lateral/humeral, central, and apical/subclavicular.
Dermatomes
- A dermatome is a specific area of skin supplied by a single spinal nerve.
- The sensory innervation of the breast primarily originates from spinal nerves T3-T5 .
Learning Objectives
- Describe the structure of the breast.
- Describe the arterial supply and venous drainage of the breast.
- Describe the dermatomal innervation of the breast.
- Describe the lymphatic drainage of the breast.
Clinical Considerations
- Breast cancer is most prevalent in the upper outer quadrant.
- Lesions are described using a clock-face reference system on the breast.
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Description
Explore the intricate structure and position of the breast, including its composition of fibrous, fatty, and glandular tissues. This quiz covers the anatomical landmarks, including the axillary tail of Spence and associated muscles, as well as common breast cancer development areas. Test your understanding of breast anatomy with this informative quiz.
