User:Mohammed Fathy Bayomy/sandbox

= Anatomy of Female Breast and Axilla =

Definition
Breast is considered modified sebaceous or sweat gland, because it lies in superficial fascia

Histologically

 * Composed of 15-20 lobes that open independently (by separate opening in summit of nipple through lactiferous duct (15-20)
 * Each lobe is composed of number of lobules, which are aggregations of acini
 * Breast gland is embedded in subcutaneous fat & anchored to overlying skin & underlying pectoral fascia by fibrous bands called ligaments of Cooper that divide lobes from each other which together with fat are responsible for roundness of breast

Extensions

 * Adult female breast extends from level of 2nd rib to level of 6th rib & from lateral border of sternum to midaxillary line

Floor
Breast rests on:


 * Pectoralis major muscle, (its upper medial 2/3)
 * Serratus anterior muscle & external oblique muscle (its lower lat. 1/3)

Nipple & Areola

 * Nipple is surrounded by areola
 * In male & pre-pubertal female, nipple & areola are small, & breast tissue does not usually extend beyond areola

Each breast is divided into

 * Central portion
 * Upper outer quadrant: con­tains axillary tail
 * Upper inner quadrant
 * Lower outer quadrant
 * Lower inner quadrant

Axillary tail of Spence

 * It is prolongation from upper outer quadrant of gland along lower border of pectoralis major muscle. Then it passes through opening in axillary fascia called (foramen of Langer) to enter axilla
 * It is in close relation to pectoral group of LNs
 * It is only portion of breast that lies deep to deep fascia

Arterial supply

 * Axillary artery: through superior thoracic, acromiothoracic & lateral thoracic arteries.
 * Internal mammary artery: through its anterior perforating branches.
 * 2nd, 3rd, 4th intercostal arteries: through their lateral cutaneous branches.

Venous drainage

 * veins of breast end in axillary & internal mammary veins

Classical description
There are 2 sets of lymphatics

Lymphatics of parenchyma
Arranged in 2 plexuses

Subareolar plexus of Sappey

 * It drains superficial part of gland with areola & nipple
 * It drains into deep plexus

Deep plexus (over pectoral fascia)

 * It drains deep part of gland & subareolar plexus
 * It drains into axillary L.Ns. (pectoral group) & internal mammary L.Ns through pectoralis major muscle
 * Lymphatics passing to pectoral group will pass to central group of axillary lymph nodes (at base of axilla) then to apical group of axillary L.Ns (at apex of axilla) then to supraclavicular LN
 * Lymphatic from inner lower quadrant of breast communicate with subperitoneal lymph plexus through linea alba, so malignant cells of breast may reach peritoneal cavity & implant on liver & through falcifrom ligament, malignant nodule may appear around umbilicus (Sister Joseph nodule). Also, cancer cells may drop in pelvis & implant on ovaries causing (Krukenberg's tumour) or nodules in Douglas pouch

Lymphatics of overlying skin (except nipple & areola)

 * From outer part to axillary LNs
 * From upper part to supraclavicular L.N.s (directly)
 * From inner part to internal mammary L.N.s


 * 1) They communicate with cutaneous lymphatics of other breast
 * 2) Unilateral cancer may give metastases to other breast through this route if ipsilateral lymphatics were blocked. (Doubted)

Modern description
It claims that role of lymphatic plexuses have minor role & lymphatics accompany major blood vessel to drain into:


 * Axillary lymph nodes (75%)
 * Supraclavicular (SC) lymph node
 * Internal mammary nodes (25%)
 * Posterior intercostal lymph nodes (5%) near heads of ribs

Sentinel lymph node (or nodes)
First node in regional lymphatic basin to which tumour drains

Anatomical groups

 * Anterior (pectoral) group: along lower border of pectoralis minor muscle
 * Posterior (subscapular) group: along posterior axillary fold
 * Lateral (humoral) group: around upper part of humerus
 * Interpectoral (Rotor) group: between two pectoralis muscles
 * Central group: in base of axilla
 * Apical group: in apex of axilla

Levels of axillary nodes
These nodes are in continuity with each other but con­cept of axillary node levels is useful when discussing extent of axillary node surgery


 * Level I (low axillary): inferolateral to pec­toralis minor.
 * Level 2 (midaxillary): posterior to pectoralis minor, Rotter’s (interpectoral) nodes considered level II and are located between pectoralis major & minor muscles.
 * Level 3 (apical or infraclavicular): superomedial to pectoralis minor.

Internal mammary lymph nodes (IMLN)

 * Located in first to fifth intercostal spaces (first to third most commonly involved), 3–3.5 cm from midline alongside internal thoracic artery.
 * Communicate with lymph nodes in opposite breast.
 * Communicate with lymph nodes in abdominal wall.