Boob anatomy

3 different effects of cancer on the breast's appearance

1. Scirrhous (hard) tumors of the berast often place traction on suspensory ligaments (Cooper's ligaments) and cause dimpling of the skin of the breast 2. blockage of superficial lymphatics and lymph drainage leading to edema and the "peau d'orange" sign 3. cancer of the lactiferous duct may produce nipple inversion and retraction.

Three major breast arteries

1. internal thoracic artery (a branch of the subclavian artery) 2. Lateral thoracic artery 3. lateral mammary branches of the lateral cutaneous branches of the posterior intercostal artery

What are the arteries/veins in the breast

1. internal thoracic artery and vein 2. lateral mammary branches of the lateral cutaneous branches of the posterior intercostal artery and vein 3. lateral thoracic artery and vein

Drainage of the breast is mainly via which two veins

Lateral thoracic vein internal thoracic veins --> veins in the breast run parallel to the arteries

Internal thoracic artery

a branch of the subclavian artery that supplies most of the medial breast. Branches of this perforate the anterior chest wall on each side of the sternum and form the perforating branches of the ITA. Some divide into MEDIAL MAMMARY BRANCHES, supplying the medial breast.

Lumpectomy

a breast-conserving surgery in which only the tumor is removed from the breast.

axillary process (axillary tail of Spence)

a portion of the breast that extends toward the axilla. This may extend into the apex of the axilla. midaxillary line extends vertically from the middle of the apex.

retromammary space

a potential space (a space that is normally empty but has the potential to expand to a larger size) fillwed with loose connective tissue separating the breast from deep fascia and allows some degree of movement.

Mastectomy

a surgery that removes ALL breast tissue superifical to the retromammary space, typically including all or part of the pectoral fascia

suspensory ligaments of the breast

aka Cooper's ligaments. --connective tissue that surround ducts and lobules of the mammary gland that condense. These ligaments help support lobules of the breast and firmly attach the breast to overlying skin. -->carcinoma of the breast creates tension on these ligaments, causing pitting of the skin.

metastasis

as lymph travels toward the heart, foreign particles, including cells, may enter. Thus, the lymphatic system may carry cancer cells from one part of the body to another lymphatic drainage is important due to its role in this of tumor cells.

What two places do lymph vessels normally drain in the breast?

axillary or parasternal nodes (but can also drain to abdominal lymph nodes or to the contralateral breast) --> obstruction of lymphatic drainage pulls on connecitve tissues and results in the change in breast appearance associated with breast cancer.

Lateral thoracic artery

begins as subclavian which becomes the axillary artery which branches to become this artery which supplies most of the lateral breast via LATERAL MAMMARY BRANCHES.

Lymphatic vessels of the breast

carry excess interstitial fluid called lymph toward the heart. -These vessels follow veins, pass through discrete lymphoid tissues such as lymph nodes and allow lymph to enter the venous system at the junction of the internal jugular subclavian. --> if lymphatic drainage is blocked, fluids accumulate in interstitial spaces, resulting in edema.

drainage from medial breast

drains into PARASTERNAL NODES located on the deep surface of the thoracic wall. -these drain into the venous system via the bronchomediastinal trunks or to the opposite breast or to subdiaphragmatic (abdominal) lymph nodes. -thus, cancer cells here can metastasize to the contralateral breast or to the liver.

drainage from Superior breasts

goes to: INTERPECTORAL NODES (aka Rotter's nodes around 12 oclock) (found deep to the pectoralis minor) or... CENTRAL AXILLARY NODES (middle of armpit) (via pectoral nodes)

drainage from lateral and superior breast

greater than 75% of all lymphatic drainage is to the CENTRAL AXILLARY LYMPH NODES (armpit) via the PECTORAL NODES (9 oclock). (from here, lymph drains through the infraclavicular then supraclavicular nodes before entering the venous system)

axillary nodes (what are they and where do they drain)

include apical, humeral, central, pectoral, and subscapular nodes drain into clavicular nodes and then the subclavian vein.

Where do secretory lobules drain?

into a series of 10-15 lactiferous ducts. (lead to a dilated portion deep to the nipple called the lactiferous sinus) Eacho f the lactiferous ducts opens independetly onto the nipple -->adenocarcinomas of the breast usually arise from ductal epithelium

parasternal nodes (where are they and where do they drain)

located on the deep surface of the thoracic wall drain into the subclavian vein

Lateral thoracic vein

most of the breast drains to this which drains to the axillary vein which becomes the subclavian vein (at the first rib) which joins the internal jugular vein and forms the brachiocephalic vein this vein --> axillary vein --> subclavian vein --> internal jugular vein --> brachiocephalic vein

breast MRI

particularly useful for women who are at high risk for breast cancer, for male breast cancer, for post-operative evaluation, and for women who have had reconstructive surgeries or breast augmentation that make imaging difficult.

mediolateral oblique (MLO) view

shows a lateral view and is taken at an angle parallel to the pectoral muscle. --> from the superomedial to inferolateral aspect of the breast -always shows the pectoralis major muscle and the axillary tail -pectoral muscle should extend to or below the nipple. This view maximizes the visualization of tissue of the lower axilla and upper outer quadrant the top part of this type of image represents the superior half of the breast and the bottom part of the image represents the inferior half of the breast. When you view it, it's like looking sideways at the breast.

craniocaudal (CC) view

shows breast horizontally -the nipple is centered or pointed slightly medially --> allows for visualization of the medial tissues that cannot completely be seen in an MLO view. -may show the pectoral muscle on the posterior edge of the breast the top part of a this type of image represents the lateral part of the breast, and the bottom part of the image represents the medial breast --> when you view it, it's like looking down on the breast

internal thoracic vein

some of the medial breast drains to this vein on either side of the sternum. This drains into the brachiocephalic vein

imaging of the breast; 2 types of views

the breast is compressed in order to separate glandular tissue and to improve imaging resolution. 1. craniocaudal (CC) view 2. mediolateral oblique view (MLO)

Nipple innervation

the fourth intercostal nerve, a branch of spinal nerve T4.

Lateral mammary branches of the lateral cutaneous branches of the posterior intercostal artery

the second to fourth posterior intercostal arteries form this. it supplies the deep structures of the lateral breast.

What two nerves are often injured during breast surgery and what does this cause?

thoracodorsal - innervates latissiumus dorse and may result in weak extension of the arm long thoracic nerve - supplies the serratus anterior. Damage may result in a "winged" scapula and difficulty raising the arm.

4 quadrants of the breast

upper inner quadrant; Superomedial breast --> 15% of breast cancer (12-3 in clock system) upper outer quadrant; Superolateral breast --> 60% of breast cancer (9-12 in clock system) lower inner quadrant; inferomedial breast --> 10% of breast cancer (3-6 in clock system) lower outer quadrant; inferolateral breast --> 5% of breast cancer (6-9 in clock system)

sensory innervation of the breast

via anterior and lateral cutaneous branches of the second to sixth intercostal nerves. -->these nerves extend horrizontally from the sternum and lateral thorax.