Breast Anatomy PDF

## The Breast ### Introduction - Location - Shape - Size - Extent - Component parts - Clinical anatomy ### Modified Sweat Gland - A modified sweat gland present in both sexes. - Develops in females after puberty and secretes milk. - It's an accessory organ of the female reproductive system. -...

## The Breast ### Introduction - Location - Shape - Size - Extent - Component parts - Clinical anatomy ### Modified Sweat Gland - A modified sweat gland present in both sexes. - Develops in females after puberty and secretes milk. - It's an accessory organ of the female reproductive system. - An apocrine gland is situated on superficial fascia of the pectoral region & small portion (*axillary tail*) pierces deep fascia to lie in the axilla. - In young adult females, it is spherical and later pendulous. ### Location - Vertically extends from 2nd to 6th rib. - Horizontally, at the level of the 4th costal cartilage from the lateral sternal border to the midaxillary line. - Superior laterally prolongs laterally and pierces the deep fascia, which is known as the foramen of Langer to lie at the 3rd rib. - This part is known as the axillary tail of Spence. ### Structure of The Breast - Deep relation: Retro mammary space of loose areola tissue, deep pectoral fascia, pectoral major, serratus anterior & external oblique abdominis. - Structure of breast: Skin, parenchyma and stroma. - Skin: It encloses the breast and forms the following: - **Nipple:** A conical projection just below the center of the breast at the 4th intercostal space. It's pierced by 15-20 lactiferous ducts. It contains circular & long smooth muscles which can erect or flatten. It has few modified sweat and sebaceous glands rich in nerves. - **Areolar:** A pigmented area at the base of the nipple. It's rich in modified sebaceous glands. It becomes enlarged during pregnancy & lactation. - The formation of Montgomery tubercles secretes oil that lubricates the nipple and areola. It's fat-free. ### Stroma - **Stroma:** Forms supporting framework of the gland that divides into fibrous stoma which forms septa known as suspensory ligament of Cooper, anchoring the skin to the pectoral fascia. - Infiltration of this ligament by cancer cells causes fixity of the breast, leading to puckering of the skin. - **Fatty stroma:** Forms bulk of the breast and is distributed all over the breast except the nipple and areola. ### Parenchyma - **Parenchyma:** Made of glandular tissue that secretes milk. It consists of 15-20 lobes. - Each lobe is a cluster of alveoli and drained by lactiferous ducts. - Each duct is dilated into lactiferous sinus beneath the areola. - Lactiferous ducts converge at the nipple like spokes. ### Clinical Anatomy - The breast is the common site for tumors. - The lymphatic channel is the pathway for carcinoma. - Cancer cells may infect the suspensory ligament making the breast fixed. - Contraction can cause retraction or puckering of the skin. - Tumors in the breast can be benign or malignant. - Benign tumor papilloma can be treated by surgical excision of the growth. - Some of the characteristics of breast cancer: - The area is reddish with dimpling of the skin or pitting. - Malignant tumor, breast cancer, is treated by the affected side or both sides, using a surgical procedure known as a radical mastectomy. ### Polymastia - Extra breast most commonly occur along the milk line, usually just underneath the normally located breasts or nipples. - However, they have also been noted in ectopic sites such as the back or the buttock. - These accessory tissues may undergo malignant transformation and should be removed. ### Lymphatic Drainage of Breast - It's important in connection to disease spread. - Divided into superficial and deep components with both freely communicating. - Superficial nodes drain the skin of the breast except areola and nipples. - Deep nodes drain the parenchyma, nipple and areola. - The nodes are arranged into lateral upper and lower quadrant & medial upper and lower quadrant. - Lateral part drain into axillary & infraclavicular nodes. - Medial part drain through intercostal spaces to parasternal nodes. - The two communicate due to pressure from clothing, through intercostal nodes to posterior intercostal nodes, inferiorly to sub diaphragmatic to peritoneal nodes. - 70% to axillary, 20% to mammary, 5% to post. Intercostal nodes. ### Blood Supply - (i) Internal thoracic perforates 2nd to 6th intercostal spaces. - (ii) Lateral thoracic artery. - (iii) Superior thoracic artery. - (iv) Acromio-thoracic branch.