Breast Anatomy PDF

( UPPER LIMB ) “ Breast “ The female breast (mamma) is formed by the mammary gland (specialized accessory gland) secreting milk. Shape & position: The breast is conical in shape with its base extending from the second to the sixth ribs and from sternum (lateral borde...

( UPPER LIMB ) “ Breast “ The female breast (mamma) is formed by the mammary gland (specialized accessory gland) secreting milk. Shape & position: The breast is conical in shape with its base extending from the second to the sixth ribs and from sternum (lateral border) to the midaxillary line. It presents in super cial fasola, except axillary tail (which pierces deep fascia at lower border of pectoralis major and enters axilla). Muscle bed of breast (muscles under it) are pectoralis major the main muscle bed) with serratus anterior & external oblique. It consists of 15-20 lobes separated by brous septa which is more developed in upper part near skin forming the suspensory ligament (Cooper's ligament). Breast is separated from the deep fascia under it by it by a layer of loose arcolar tissue called retromammary space. Each lobe is formed of acini (secreting milk) and transmits the milk by a lactiferous duct that opens into the nipple and before its enc forms lactiferous sinus (ampulla). Each lobe has one duct so there is 15-20 ducts in breast. Nipple & Areola: Nipple: lies opposite to 4th intercostal space, but if the breast is large, the nipple will be lower. It has 15-20 openings. Areola: is dark pink-brownish circular area surrounding the nipple, it changes to dark brown by melanin at rst pregnancy and still for ever. Arcola contains areolar sebaceous glands which is so large forming visible cutaneous tubercles. Both nipple & arcola have no fat under its skin. Blood supply: 1. Internal thoracic a. (perforating branches of it). 2. Lateral thoracic a. 3. Intercostal arteries. 4. Thoraco-acromial a. Note: Veins corresponds to arteries. ( Lymph drainage ) Lateral quadrant & central part: drain into anterior (pectoral) group. Upper quadrant: drain into apical group of lymph nodes Lower quadrant: into lymph plexus of rectus sheath & subphrenic plexus. Medial quadrant: into internal thoracic (parasternal) nodes. Some lymphatics of medial part cross opposite breast (intermammary lymphatics). Clinical notes : Male breast may en arge in some diseases (gynecomastia). Suspensory (Cooper's) ligament may be invaded by breast cancer causing dimpling of skin (peau d'orange) by their shrinkage. Breast cancer may invade retromammary space into the muscle causing xation of breast  Breasts at puberty assume their hemispherical shape under the in uence of ovarian hormones, and their size increase by fat deposition. ( AXILLA ) De nition: Axilla (armpit) is a pyramidal space between upper part of arm & the side of he chest. It has an apex, base & 4 walls. Apex of axilla: (upper end) Anteriorly: clavicle. Posteriorly: upper end of scapula. Medially: outer border of 1" rib. Base of axilla: (lower end) Anteriorly: anterior axillary fold (pectoralis major). Posteriorly: posterior axillary fold (teres major & latissimus dorsi tendons). Medially: chest wall. Note: Base of axilla is formed by skin & fascia that connect the anterior & posterior axillary walls. Walls of axilla: (4 walls) Anterior wall: pectoralis major, pectoralis minor, subclavius & clavipectoral fascia. Posterior wall: teres major, latissimus dorsi & subscapularis. Lateral wall: bicipital groove of humerus, biceps brachii & coracobrachialis. Medial wall: upper 4-5 ribs, intercostal spaces & serratus anterior. Contents of axilla: 1. Brachial plexus (cords & branches). 2. Axillary a. (and its branches). 3. Axillary v. (and its tributaries). 4. Axillary lymph nodes (and lymph vessels). 5. Axillary fat. 6. Axillary tail of breast. 7. Axillary sheath. Axillary sheath: is a continuation of prevertebral layer of deep fascia of neck. It contains: (1) axillary a. (2) cords of brachial plexus. Clavipectoral fascia: Strong brous sheet between clavicle (above) (enclosing the subclavius m.) & pectoralis minor (below). Its lower part (after pectoralis minor) forms suspensory ligament of axilla. Its upper border forms costocoracoid ligament (between 1 rib & coracoids process). It is pierced by : (1) lateral pectoral n. (supplies pectorals major). (2) thoraco-acromial a. (from 2nd part of axillary a.). (3) cephalic v. (drains into axillary v.). (4) lymph vessels (drain into apical lymph nodes). Deltopectoral groove: Groove between deltoid & pectoralis major. It contains: (1) deltoid branch of thoraco-acromial a. (2) uppermost part cephalic v. (3) deltopectoral lymph node.