Surface anatomy of anterior thoracic wall, lung surface marking, pleural reflections By Amanda tatar

Objectives Explain lymphatic drainage of the breast and its importance in the spread of cancer Describe the surface markings of the lungs and pleural reflections Identify important surface landmarks on the anterior thoracic wall Use the sternal angle (of Louis) to accurately number the ribs on a living subject

Anatomy of the breast Both sexes Mammary glands Suspensory ligaments: attach glands to dermis 15-20 lobules → parenchyma of mammary glands 1 lobule → lactiferous duct → nipple Lactiferous sinuses – dilated area Both males and females have breasts, but the mammary glands are more developed in women. In women they are important for lactation and are an accessory gland of the female reproductive system. Male mammary glands are functionless and just a few cords or ducts. Mammary glands attach to the dermis (layer of skin) by suspensory ligaments of Cooper. These are especially well developed in the superior (upper part) breast to support the mammary gland lobules. 15-20 lobules constitute the parenchyma of the mammary glands. Each lobule opens up onto the nipple thorough a lactiferous duct. Every duct has a dilated part just deep (further in) to the areola. This diagram is showing three different layers/types of breast tissue. Superiorly (yellow one) it shoes the suspensory ligaments and lobules of fat Middle it shows the mammary glands in a non-lactating Inferiorly it shows the mammary glands in a lactating breast

Surface anatomy of the breast Midaxillary line Ribs 2 → 6 Lateral border of sternum to midaxillary line Axillary process 2/3 over pectoralis major 1/3 over serratus anterior Nipple over 4ics = MEN Axillary process Transverse = lateral (side) border of the sternum out to the midaxillary line (line down from armpit). Vertical = Ribs 2 down to 6 The nipple of the breast usually overlies the 4th intercostal space (ics), but in women is much more variable so unreliable as a surface landmark of anatomy All of the breast overlies fascia of either the pectoralis major muscle (2/3) or the serratus anterior muscle (1/3). Axillary process/Tail of Spence: The tissue of the breast may extend out along the border of the pectoralis major muscle in the direction of the axillary fossa (indentation of the armpit). This extension of the breast tissue is called the axillary (armpit) process (extension). Clinical relevance: pathological breast quadrants

Surface anatomy of breast Intermammary cleft Body of sternum Axillary tail Anterior axillary fold Areola Nipple Areolar is pigmented area, altered by hormones after pregnancy Anterior axillary fold – anterior fold of the axilla area – armpit Supernumerary nipple = extra nipple to varying degrees of completeness. Occur along two milk lines - line on which nipples may appear – similar to a nipple line of dog or pig Supernumerary nipple Xiphoid process

Vasculature of breast Arterial supply: Medial mammary branches of anterior intercostals from internal thoracic arteries Lateral thoracic from axillary arteries Thoraco-acromial from axillary arteries Posterior intercostals from thoracic aorta Internal thoracic artery branches → medial mammary from anterior intercostals Axillary artery → lateral thoracic + Thoraco-acromial Thoracic aorta → posterior intercostals

Arterial supply continued RCC LCC AXILLARY LSC RSC In Th BCA ARCH Arch – aortic arch PIC – posterior interscostals LCC/RCC – left/right common carotid BCA – brachiocephalic artery LSC/RSC – left/right subclavian AXILLARY – axillary In Th – Internal Thoracic AIC – Anterior intercostasl Med Mam – Median mammary Tho-Acr – thoraco-acromial Lat-Tho – Lateral thoracic AIC Tho- Acr PIC Lat-Tho Med Mam HEART

Lymphatic drainage of breast Lymphatics – drainage All from breast → sub-areolar plexus then: Axillary: 75 % Parasternal Abdominal Lymphatic system enables drainage of excess tissue fluid, leaked plasma, removal of debris and infection All lymph from breast goes into the sub-areolar plexus. From here, it then drains into three main types of lymph nodes: Axillary: 75 %, especially from the lateral breast quadrants Parasternal or opposite breast Abdominal (inferior phrenic) (Axillary drain into the infra or supra clavicular nodes and then into subclavian lymphatic trunk Parasternal drain into bronchomediastinal trunks)

Lymph continued Axillary Nodes: Pectoral Humeral Subscapular Central Apical Axillary nodes → supra/infra clavicular → subclavian trunk Parasternal → bronchomediastinal

Importance of lymph Breast carcinoma → metastasis ↑ communication of lymph Metastasis can be extensive Left – normal Right - carcinoma

Lung pleurae Visceral – adherent to lungs Parietal – lines pulmonary cavities Between = pleural space = serous fluid: Reduces friction – respiration Surface tension - cohesion The pleurae can be imagined with a balloon. Imagine your fist to be a lung. Push your fist into a blown up balloon (until you wrist). The balloon is in contact with your skin (visceral) but also billows out around your fist (parietal). The visceral pleura is attached to the lungs – balloon in contact with your fist. The parietal pleura lines the pulmonary cavities, adhered to the thoracic wall, mediastinum, diaphragm. IN between the pleural layers is the pleural cavity – a potential space (ie not an actual space but where a space can form) in which serous pleural fluid is contained. This is a lubricant, enabling the layers of pleura to slide over one another as needed in respiration. Also provide cohesion like water between glass plates.

lungs in prosection Sternum Right lung Left lung VISCERAL PLEURA Prosection of thorax External intercostal muscles Ribs Costal margin

THORACIC CAVITY IN PROSECTION Sternum VISCERAL PLEURA ON RIGHT LUNG Prosection of right lung pulled back to see the parietal pleura. Pleura makes it shiny PARIETAL PLEURA (costal) Costal margin

Parietal pleura parts Costal: Mediastinal: Diaphragmatic: Cervical: Internal thoracic wall surfaces Endothoracic fascia separates Mediastinal: Lateral mediastinum Diaphragmatic: Diaphragm Cervical: Thorough superior thoracic aperture 2-3cm above clavivles There are four parts to the parietal pleura: Costal – covers the internal thoracic wall; ribs, sternum, costal cartilages, intercostal muscles, thoracic vertebrae sides – separated from the wall by endothoracic fascia Mediastinal – central compartment of thorax; covers lateral sides of it Diaphragmatic – diaphragm Cervical – lung extends superior to clavicle, hence parietal pleura does too. This is about 2-3 cm superior to the clavicles

Pleural reflections – parietal pleura Sternal - Anteriorly Sharp Costal → mediastinal Costal - Inferiorly Costal → diaphragmatic Vertebral - Posteriorly Rounder Abrupt lines where the parietal pleura changes direction from one wall of the pleural cavity to another = pleural reflections

Parietal and visceral pleural markings 2cc → 4cc 4cc → 6cc inferiorly (R) 4cc → 6cc curved (L) 6cc → 8cc midaxillary 10 rib posteriorly PARIETAL: 2cc → 4cc 4cc → 6cc inferiorly (R) 4cc → 6cc curved (L) 6cc → 8cc midclavicular 8cc → 10 rib midaxillary 12 rib posteriorly EVEN NUMBERS: Visceral = 2 4 6 8 10 Parietal = 2 4 6 8 10 12

recesses Pleural cavities not full in expiration → recesses Costodiaphragmatic Costomediastinal Costomediastinal is roughly where cardiac notch is – but not the cardiac notch

Surface anatomy – anterior planes Jugular notch Sternal angle Median (midsternal) Midclavicular - two MEDIAN LINE Median – middle Midclavicular – midpoint of clavicles, parallel to median line MIDCLAVICULAR LINES

SURFACE ANATOMY – ANTEROLATERAL PLANES Axillary fossa Anterior axillary – along ant. fold (pectoralis major) Midaxillary – axillary apex ↓ Posterior axillary – along post. fold (latissimus dorsi, teres major) Anterior axillary Midaxillary Anterior axillary – along anterior axillary fold formed by the border of pectoralis major Midaxillary – from the axillary apex and down inferiorly, parallel to the anterior axillary Posterior axillary – posterior axillary fold by latissimus dorsi and teres major, parallel Pectoralis major, latissimus dorsi and teres major are all thoracic muscles you will learn about  Posterior axillary

Important features to identify

Important levels Jugular notch = T2 Sternal angle Xiphoid process = T9 T4/T5 2cc Bifurcation of bronchi Counting ribs from here Xiphoid process = T9 Level of T4/T5 – very important landmark to know. From there, travel outwards with your fingers to palpate a rib – this is the second rib. Moving your fingers down slowly, you can plapate the ribs numerically

Counting the ribs * Level of T4/T5 – very important landmark to know. From there, travel outwards with your fingers to palpate a rib – this is the second rib. Moving your fingers down slowly, you can plapate the ribs numerically

Correspondence! T2 T4/T5 T9

CLINICAL RELEVANCE – _?_ thorax! Accumulation of ‘stuff’ into pleural cavity Something is broken or torn open Pneumothorax – air Hydrothorax – fluid (from effusion) Hemothorax – blood Chylothorax - lymph Build up of fluid etc!

quiz Q. Most of the lymphatic drainage of the breast goes to the other breast? False – most drains to the axillary nodes Q. The parietal pleura crosses the midaxillary line at 8cc? False – crosses the midclavicular line at 8cc, midaxillary at 10cc. Visceral pleura crosses the midaxillary line at 8cc Q. Sternal angle is at the level of T3/T4? False – T4/T5 A B A = jugular notch aka suprasternal notch B = midclavicular line – midpoint of clavicle

Thank you! mzyart@nottingham.ac.uk In this powerpoint I used: Point of interest: Pleural effusion – fluid on the lungs mzyart@nottingham.ac.uk In this powerpoint I used: Moore and Agur Teach me anatomy Acland Anatomy Videos Google images Please email me any questions or come ask me at the end!