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MAMMARY GLAND

LECTURE BY DR. ABDUL WAHEED ANSARIPROF. OF ANATOMY,

MES MEDICAL COLLEGE,PERINTALMANNA.KERALA. INDIA.

Tuesday, May 2, 20231

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THE SPECIFIC LEARNING OUTCOMES

• 1. Identify the gross anatomical features- location, extent, deep relations, and structure and blood supply of breast.

• 2. Distinguish normal histology of lactating and non-lactating phase of breast.

• 3. Analyze the lymphatic drainage of breast and evaluate its clinical importance.

• 4. Correlate the normal development of breast and its clinical significance.

• 5. Interpret the normal mammogram.

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REFERENCES • 1. Clinically Oriented Anatomy-Keith Moore, 6th edn.

Chapter 1 pages 98, 99,101,103-106.• 2. Clinical Anatomy by regions –Snell, 8th

edn.chapter-9 pages 427-432.• 3. DiFiore’s Histology, 12th end. Chapter 21, pages

549-555.• 4. Langman’s embryology-Sadler, 12th edn.chapter21

page 342.• 5.http://www.medscape.org/viewarticle/548921_3• 6.http://www.oucom.ohiou.edu/dbms-witmer/downloads/

2012-04-24 DashnerRPAC-BREAST ANATOMY.PDF• http://slideplayer.com/slide/5725038/

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GROSS ANATOMY OF BREAST

• All mammals have mammary glands.• The mammary glands are modified skin

glands (sweat glands).• In human beings the functional breast is

seen in adolescent females and nursing mothers.

• In some genetic disorder-Klienfelter syndrome males also have gynecomastia.

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Mammary glands are located on anterior chest wall in superficial fascia

• Longitudinally it extends from 2nd rib to the 6th rib. Horizontally from side of breast bone to the mid axillary line, the tail of breast extends in the axilla.

• An area around the nipple is called as areola, it is rosy pink before pregnancy and it changes its color to dark black area during first pregnancy and never returns to spinster stage color.

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GROSS ANATOMY OF BREAST

• The gland is composed of mostly fat and admixed with the compound tubuloalveolar pattern of glands.

• The mammary gland functionally is an apocrine gland where apart of breast cells are shed into the secretion and constitute the milk.

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THE COOPER’S LIGAMENTS

• Cooper's ligament, also known as the suspensory ligaments and ligamenta suspensoria mammaria, are connective tissue in the breast that maintain structural integrity.

• They fix the breast from skin to the pectoral fascia.

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15-20 lactiferous ducts open under the nipple

• The human breast rests on the pectoral fascia and pectoralis major, minor, serratus anterior and external obliques abdominis muscles.

• The malignant breast get adhered to the pectoral fascia and underlying muscles when it infiltrates the deep structures.

• Some additional or ectopic breast may be found all along the mammary line from axilla to inguinal region.

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THE ECTOPIC BREAST

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THE BLOOD SUPPLY OF BREAST

• The blood supply to the breast is derived from 3 sources. The predominant supply of blood comes from the perforating branches of the internal mammary arteries, derived from the thyrocervical trunk of subclavian.

• The breast is further supplied by the lateral thoracic and thoracoacromial arteries (branches of the axillary artery) as well as posterior intercostal arteries (branches of the thoracic aorta).

• Venous drainage of the breast is mainly accomplished by the axillary vein. The subclavian, intercostal, and internal thoracic veins drain the breast. The posterior intercostal veins drain the breast and communicates with the vertebral veins and that are continuous with the intracranial vein, and this forms the route through which cancer may spread to cranial cavity and back bone.

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BLOOD VESSELS SUPPLYING THE BREAST

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THE LYMPHATIC DRAINAGE OF BREAST• The lymphatic drainage of the

breast deserves special attention, due to its role in the metastasis of cancer cells.

• The majority of lymph (>75%), particularly from the lateral quadrants, drains to the axillary lymph nodes.

• The remainder of lymph drains to either the parasternal nodes or the opposite breast (medial quadrants) or the inferior phrenic nodes (lower quadrants).

• The sub areolar plexus drains by collecting trunks into the axillary nodes.

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CLINICAL ASPECT OF BREAST LYMPHATIC DRAINAGE

• Peau-d’orange = A pitted or dimpled appearance of the skin, especially as characteristic of some cases of breast cancer or due to cellulite.

• Dimpling of the skin over the breast is due to involvement of the Cooper’s ligaments.

• Blockage of the dermal lymphatics of the breast due to malignancy results in oedema of the skin.

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FREQUENCY OF BREAST CANCER IN ALL QUADRANTS

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NORMAL HISTOLOGY OF BREAST • Non-lactating phase• Embedded in the

surrounding connective tissue there are inactive tubular portions of breast tissue is recognized.

• The alveoli develops during early weeks of pregnancy and lactation begins after birth.

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THE LACTATING BREAST TISSUE• The secretory units are alveoli,

which are lined by a cuboidal or columnar epithelium.

• A layer of myoepithelial cells is always present between the epithelium and the basement membrane of the branches of the lactiferous duct and the alveoli.

• Secretion of milk proteins proceeds by exocytosis (merocrine secretion), whereas lipids are secreted by apocrine secretion.

• Colostrum is the first formed milk rich in IgE-immunoglobolins. It is yellow in color.

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THE NORMAL DEVELOPMENT OF BREAST

• Human breast is an ectodermal in origin.

• Similar to any skin gland, sweat gland – breast is a modified sweat gland.

• There is a milk line extending from axilla to the inguinal region.

• In human all tissues disappear and remaining part develops as breast.

• The additional breast or ectopic breast can be present in axilla or along the milk line.

• In cats and dogs the milk line extends from fore limb to hind limb regions.

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CONGENITAL FORMS OF BREAST

• Amazia =complete absence of breast tissue.

• Polymazia=multiple breast.

• Polythelia=multiple nipples

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WHAT IS A MAMMOGRAM?• It is a radiological study of

breast tissue.• The breast shadow is analyzed,

showing the glandular patterns, parenchymal and duct branching, fibrous elements and any nodules or calcification are noted.

• A MRI is a magnetic resonance imaging study of breast tissue, it can find cancers of breast not discovered by mammogram

• .

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Abnormal mammogram

• 1=Abnormal axillary lymph nodes

• 2=Breast tissue• 3=Cancer in the

breast tissue

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REVIEW OF BREAST ANATOMY

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The internal vertebral veins may communicate with cranial veins

• This is the route that spread the malignancy from breast to back bone or cranial cavity.

• The metastasis of carcinoma of breast to cranial cavity and back bone.

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A dermatome is a patch of skin supplied by a segmental spinal nerve

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MCQS on breast anatomy

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MCQS ON BREAST

In lymphatic drainage of the breast, the major portion (about 75%) enters eventually into which group of nodes? A. Central axillaryB. DeltopectoralC. Lateral axilllaryD. ParasternalE. Subscapular

A woman with breast cancer subsequently develops metastases in her vertebral column. The most direct route for spread of the tumor to the vertebral column was via: A. Branches of the cephalic veinB. Branches of the lateral thoracic veinC. Branches of the thoracoacromial veins D. Lymphatic vessels draining into the axillaE. Branches of the intercostal veins