Mammary gland Gbotolorun, S.C.

Introduction Most superficial structure in ant thoracic wall Situated in subcut tissue overlying pectoral ms Well developed + accessory to reproduction in females Rudimentary and functionless in males Size determined by the amt of fat surrounding glandular tissue Size and shape may result from genetic, racial & dietary factors

Transversely Vertically EXTENT Transversely from the lateral border of the sternum to the midaxillary line Vertically From the 2nd to the 5th ribs A small part may extend along the inferolateral edge of the pectoralis major towards the axilla- axillary tail of spence

2/3- rest on deep pectoral fascia overlying the pectoralis major 1/3- rests on the fascia covering serratus anterior ms Btw breast and deep pectoral fascia -retromammary space (RS) A loose CT or potential space The space contains a small amt of fat- Allows breast move over the pectoral fascia

Mammary gland attached firmly to dermis of overlying skin by skin ligaments – the suspensory ligament of Cooper fibrous condensations of the CT stroma Well developed in the superior part of the gland Help support the lobules of the gland During puberty breast increase in size bcos of increased fat deposit and glandular development The areolae and nipples also enlarge

The glandular tissue of the breast The lactiferous ducts give rise to buds 15 to 20 lobules of glandular tissue Each lobule is drained by a lactiferous duct opens independently on the nipple The ducts converge towards the nipple spokes of a bicycle wheel Deep to the areola each duct dilates – lactiferous sinus

A --Duct. B --Lobule. C --Ampulla. D --Nipple. E --Fat. F --Pectoralis. G --Chest Wall.

The areolar contains numerous sebaceous glands that enlarge during pregnancy They secrete an oily substance that lubricates the areola and nipple The breast are modified sweat glands They have no special capsule or sheath

The nipples Conical/cylindrical prominences in the centre of the areolae Devoid of fat, hair and sweat glands In young nulliparous woman usually in 4th intercostal space Position varies especially in the multiparous woman

Not a reliable guide to the 4th intercostal space Tips are fissured with the lactiferous ducts Composed mostly of circularly arranged smooth muscles

Blood supply Arterial supply Venous return Internal thoracic artery Lateral thoracic artery Thoracoacromial artery Posterior intercostal arteries Venous return axillary vein Internal thoracic vein Intercostal vein

LYMPHATIC DRAINAGE Very important=role in metatasis of cancer cells Lymph from nipple, areola and lobule of gland– subareolar lymphatic plexus Most lymph > 75% especially from lateral quadrants of breast→axillary nodes through the pectoral nodes Some drain directly to the axillary nodes/deltopectoral/supraclavicular/ interpectoral/inferior deep cervical nodes

Remaining lymph particularly from medial quadrants →parasternal nodes/opposite breast Lymph from lower quadrants → inferior phrenic (abdominal) nodes Lymph from skin of breast →axillary/inferior deep cervical/infraclavicular/parasternal nodes of both sides Lymph from axillary →infraclavicular and supraclavicular→subclavian lymphatic trunk Lymph from parasternal nodes→bronchomediastinal trunk

Nerves of the breast Anterior and lateral cutaneous branches of the 4th to 6th intercostal nerves

Clinical anatomy Breast quadrants Carcinoma of breast Mastectomy/radical mastectomy/current practice lympectomy (tumor & surrounding tissues) Gynecomastia Polymastia, polythelia and amastia