Anatomy and Development
of
Breast
(Mammary Gland)
Dr. Sama ul Haque
Objectives
 Describe the gross structure of the breast.
 Give its blood supply and lymphatic drainage.
 Discuss the development of breast and its
congenital anomalies.
Breast (Mammary Gland)
 Modified Sweat Glands of the skin
 Functional in females (Milk secretion)
 Rudimentary and functionless in males
 Shape: Hemispherical
Breast (Mammary Gland)
 Extent: Vertical:
2nd to 6th rib
(Base of the breast)
Horizontal: Lateral margin of the
sternum to the midaxillary
line
 2/3rd of the breast lies in the superficial fascia
(Pectoral fascia) lying on Pectoralis major
 1/3rd of the breast lies in the superficial fascia
lying on Serratus Anterior
Breast (Mammary Gland)
 Nipple: Conical or Cylindrical prominence in
the center of Areola (Devoid of fat, hair
& sweat gland)
Surface anatomy: 4th intercostal space lateral to
midclavicular line!!!!
 Areola: Circular pigmented area of the skin
surrounding the base of the nipple,
containing sebaceous glands
 Axillary Tail : Small part of the breast extending
(of Spence) to the axilla
Breast
Breast
Breast (Mammary Gland)
 Retromammary Space: Space filled with loose
connective tissue between
breast and pectoral fascia
 Each breast consists of 15 to 20 lobules
 Lactiferous ducts from each lobule open on the
summit of the nipple separately
 Lactiferous duct possesses a dilated Ampulla
(Lactiferous sinus) just before its termination
Breast (Mammary Gland)
 Fibrous septa separates the lobes of the
mammary gland
 Suspensory ligaments (of Cooper):
Mammary gland is firmly attached to the
dermis of the skin by these fibrous septa
forming suspensory ligaments
Breast
Arterial Supply of the Breast
 Perforating branches (Internal thoracic artery)
 Lateral thoracic artery (Axillary artery)
 Thoracoacromial artery (Axillary artery)
 Intercostal arteries
Arterial Supply of the Breast
Venous Drainage of the Breast
Nerve supply
• Anterior and lateral cutaneous branches of the
4th – 6th intercostal nerves
Quadrants
of the
Breast
Lymphatic Drainage of the Breast
 Lateral quadrants: Anterior Axillary or Pectoral
Nodes
 Medial quadrants: Internal thoracic group of
Nodes (Parasternal)
 Few lymph vessels drains into Posterior
intercostal Nodes
Lymphatic Drainage of the Breast
 Inferior quadrants: May drain into abdominal
lymph Nodes
 Some lymphatic vessels communicate with the
lymphatic vessels of the opposite breast
Lymph
Drainage
of Breast
Comparison of active & inactive phase
Changes
in
mammary
gland
Development of the Breast
 Modified Sweat glands
 First appear as bilateral bands of thickened
epidermis called the mammary lines (mammary
ridges)
 In the 7th week these lines extend on each side of
the body from Forelimb to the region of
Hindlimb
Development of the Breast
 Major part of each mammary lines disappears
shortly
 Small portion of the mammary lines in the
thoracic region persists & penetrates the
underlying mesenchyme
 Here it forms 16 to 24 sprouts which in turn give
rise to small solid buds
Development of the Breast
 By the end of prenatal life, the epithelial sprouts
canalize and form lactiferous ducts
 Initially lactiferous ducts open into a small
epithelial pit which shortly after birth
transformed into nipple
 At birth lactiferous ducts are devoid of alveoli
 At puberty alveoli and excretory ducts form due
to hormonal changes
Development Anomalies of the Breast
 Polythelia (Accessary Nipples)
 Accessary nipples have formed due to the
persistence of fragments of the mammary line
 May develop anywhere along the mammary
line but usually appear in the axillary region
Development Anomalies of the Breast
 Polymastia (Supernumerary breasts)
Occurs when a remnant of the mammary line
develops into a complete breast
 Inverted Nipple
Lactiferous ducts open in the original
epithelial pit that has failed to evert.
Development
Anomalies of
the Breast
Development Anomaly of the Breast
Gynecomastia
 Enlargement of breasts in males
 Causes




May be at puberty (Usually regresses)
Drugs side effects
Prostatic cancer therapy
Hormonal imbalance
Thank you