Breast Anatomy MBBS 1st Year | Surgery Lectures| Bailey Learned with Dr. Sandeep Sir | PW MedEd

Summary

Key Points

• The breast is defined as a modified apocrine sweat gland, extending cranio-caudally from the second to the sixth rib. 1:48
• The breast rests upon the pectoralis fascia, which covers the pectoralis major and serratus anterior muscles, while the pectoralis minor lies behind the pectoralis major. 5:16
• The chest wall, comprising ribs, intercostal muscles, and serratus anterior, is crucial for breast cancer staging, as its involvement indicates a T4a disease, unlike pectoralis major involvement. 7:30
• Surgically, the breast's true extent is from the inferior border of the clavicle to the inframammary fold, and from the lateral border of the sternum to the anterior axillary line. 12:33
• Cooper's ligaments, which connect the premammary fascia to the skin, are vital for breast support and their infiltration by tumors can cause characteristic skin dimpling. 31:18
• The breast's microanatomy is divided into glandular components, primarily the Terminal Ductal Lobular Unit (TDLU), and stromal components, including adipose tissue and suspensory ligaments of Cooper. 31:40
• Axillary lymph nodes are anatomically classified into anterior, posterior, lateral, central, apical, and interpectoral (Rotter's) groups, all draining towards the apical group. 38:35
• Breast lymphatic drainage predominantly occurs via the axillary group (75%) and the internal mammary group (15-20%) of lymph nodes. 39:54
• For surgical purposes, axillary lymph nodes are divided into three levels based on their relationship to the pectoralis minor muscle: Level I (lateral and below), Level II (at the level of), and Level III (medial and above). 43:28
• Internal mammary lymph nodes are not included in the surgical classification because they are typically managed with radiotherapy rather than surgical excision due to the absence of vital structures. 48:18