1. Surface anatomy, lung markings and pleural reflections
By Alex

2. Describe the surface markings of the lungs and pleural reflections.
Learning outcomes
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 and use the sternal angle (of Louis) to accurately number the ribs on a living subject

3. 1: Surface anatomy of the breast
The breast overlies the 2nd-6th Ribs
Overlying pectoralis major and serratus anterior
It contains ~20 lactiferous ducts opening into nipple
Nipple is located at the 4th ICS – In males and varies in females
Areola = Pigmented area around nipple
In females, the breasts contain the mammary glands – an accessory gland of the female reproductive system. The mammary glands are the key structures involved in lactation.
Mammary glands are modified sweat glands
Suspensory ligaments are formed from the fibrous stroma
The lactiferous ducts are plugged with keratin outside of lactation.
The upper left image shows the way the breast can be divided into quadrants to describe pathology

4. Lymph drainage of the breast
Deep cervical nodes
Lymph drainage of the breast
Supraclavicular nodes
Infraclavicular nodes
Major sites of drainage:
Axillary nodes - 75% (lateral esp)
Parasternal nodes - 20% (medial)
Abdominal nodes - 5% (inferior)
Lymph from axillary nodes drains to infra/supraclavicular nodes
Central axillary nodes
Subscapular axillary nodes
First point of drainage for the lobules of the gland, nipple and areola is subareolar lymphatic plexus.
Lymph from axillary nodes drains to infra/supraclavicular nodes
Lymph from parasternal enter bronchomediastinal nodes
Anterior axillary nodes

5. Lymph drainage continued…
7 main Lymph drainage sites :
Apical Axillary LN*
Central Axillary LN*
Lateral Axillary LN*
Pectoral Axillary LN *
Supra/infra Clavicular LN
Parasternal Nodes LN
Abdominal LN
*The axillary lymph nodes.

6. Breast vasculature
Medial mammary branches of anterior intercostal branches of the internal thoracic artery
Lateral thoracic branches of axillary artery
Thoraco-acromial branches of axillary artery
Posterior intercostal arteries from the thoracic aorta
Arterial supply to the medial aspect of the breast is via the internal thoracic artery, a branch of the subclavian artery.
The lateral part of the breast receives blood from four vessels:
Lateral thoracic and thoracoacromial branches – originate from the axillary artery.
Lateral mammary branches – originate from the posterior intercostal arteries (derived from the aorta). They supply the lateral aspect of the breast in the 2nd 3rd and 4thintercostal spaces.
Mammary branch – originates from the anterior intercostal artery.
The veins of the breast correspond with the arteries, draining into the axillary and internal thoracic veins

7. Clinical relevance: breast cancer
WHY DO I HAVE TO LEARN ABOUT LYMPH?
Cancer of the breast can undergo metastasis
Usually start in the lacteriferous ducts*
First site of metastasis is auxiliary nodes (most common drainage)
Palpation used for early detection of metastasis
These are known as adenocarcinomas and arise from the epithelial cells
Do to the communication of the lymphatic system around the breast the condition is difficult to manage, the spread can even reach vertebrae, cranium, abdomen and brain.

8. 2: The pleura Parietal Pleura = Adheres to the Internal thoracic wall
Visceral Pleura = Attached to the lungs
In between is the pleural space filled with serous fluid, this:
Reduces friction
Gives surface tension to push parietal pleura against thoracic wall

9. Parts of the Pleura 4 Parts:
Cervical pleura - extends superior to thoracic inlet into the root of the neck
Costal part - covers the internal surface of thoracic wall and is separated from wall by endothoracic fascia
Mediastinal part - lateral aspects of mediastinum
Diaphragmatic part - superior surface of diaphragm

10. The 3 Pleural reflections
Pleural Reflections = Pleural folds / change in direction of pleura – 1 Anterior, 1 Posterior and 1 Inferior
Sternal line – Costal Pleura continuous with mediastinal pleura Anteriorly
Costal line – Costal pleura continuous with diaphragmatic pleura Inferiorly
Vertebral line – Costal pleura becomes continuous with mediastinal pleura Posteriorly

11. Parietal and visceral pleura markings
Visceral pleura: 2, 4, 6, 8, 10 Together cc2-4 Cardiac notch to cc6 Midaxillary cc8 Rib 10 posteriorly
Parietal pleura:
2, 4, 6, 8, 10, 12
Together cc2-4
Cardiac notch to cc6
Midclavicular cc8
Midaxillary cc10
Rib 12 posteriorly

12. 3: Surface markings, planes
3 Anterior Planes
Median Plane
2x Midclavicular Plane
3 Anterolateral Planes
Anterior Axillary Plane
Midaxillary Plane
Posterior Axillary Plane

13. Other key surface lines

14. Surface markings

15. Thoracic Dermatomes Nipple - T4 Xiphoid - T7 Umbilical – T10
Suprapubic – L1
The area of skin supplies by the nerves of a single spinal root
Remember somites (lateral wall) from HDT?

16. Clinical relevance: pleural effusion
’Water on the lungs’
Excess fluid that accumulates in the pleural cavity
Can impair breathing by limiting the expansion of the lungs
Key types are:
Hydrothorax (serous fluid)
Hemothorax (blood)
Chylothorax (chyle)
* Other types - Urinothorax (urine), Pyothorax (pus)

17. Quiz Time! 1) The lymph of the breast drains mainly to the abdomen
False – Mainly axillary nodes!
2) The visceral pleura attaches firmly to the internal thoracic wall
False – Its attachment is the surface of the lungs!
3) The Sternal angle lies at the level T4/5 vertebrae
True – This is a core fact to remember!
4) The visceral pleura crosses midaxillary line at T8
True – Remember that all the levels for this are even numbers!

18. Summary The breast is lies over the 2nd to 6th ribs
Breast lymph drainage is Axillary (75%), Parasternal and abdominal
There are 2 layers to the pleura- parietal and visceral
The reflections of the pleura are: Costal, Vertebral and Sternal lines
There are 4 parts to the pleura which are named after anatomically related structures

19. Thanks for listening If you have any questions…
me:
Otherwise Good Luck this week!
Sources:
Moore and Agur- Essential Clinical Anatomy 5th edition
Grays Anatomy for Students 3rd edition
teachmeanatomy.info