Mediastinum: Sternal angle angle Lower border of T4 -It is the partition between the two pleural cavities and lungs. It includes a large number of structures -It is subdivided into: -Superior mediastinum -Inferior mediustinum : anterior, middle and posterior Superior mediastinum: Esophagus Trachea Arch of Aorta Big branches of Aortic arch Brachiocephalic ( innominate) veins Upper half os superior vena cava Phrenic nerves Vagi nerves Middle mediastinum: Pericardium Heart Pulmonary trunk Ascending Aorta Lower half of SVC Upper part of IVC Bifurcation of trachea Posterior mediastinum: Descending thoracic Aorta Azygos and hemiazygos veins vagi ِ Sternal angle angle Lower border of T4

Pleura: -Completely close sac invaginated by the lung from the medial side -Parietal pleura and visceral pleura Subdivision of parietal pleura 1- cervical 2- Costovertebral 3- mediastinal 4- diaphragmatic

Lines of pleural reflections: 0, 2, 4, 6, 8, 10 and 12 Blood supply = thoracic wall Nerve supply = lungs

Lungs: Apex, base, costal surface, medial surface 3 borders; anterior, inferior and posterior

Mediastinal surface Hilum containing the root of the lung Vertebral surface Hilum of the lung: It is the part of the mediastinal surface which gives passage to the structures forming the root of the lung Root of the lung: 1- Bronchus (Rt, Lt) 2- Pulmonary artery (superior) 3- Pulmonary veins (sup., inf.) 4- Pulmonary nerve plexus 4- Lymph nodes 5- Bronchial vessels (Aorta, Azygos)

Lobes and fissures of lungs: Left lung: Oblique fissure 21/2 inches below apex opposite 3rd Th.V. till inferior border opposite 6th Costochondral junction 2 lobes: superior and inferior Lobes and fissures of lungs: Right lung: Oblique fissure Horizontal fissure: from ant. border opposite 4th costal cartilage till oblique 3 lobes: sup., middle and inf. Differences between Rt, Lt lungs: 1- size and weight 2- length and breadth 3- anterior border 4- hilum How to identify the right and left lungs?

Surface anatomy of the lungs: 0, 2, 4, 6, 6, 8, 10 Applied Anatomy: -Bare area of pericardium -Pericardial puncture -Stab wound in the midaxillary line .below 10th rib . between 8-10 . above 8th rib -Pneumothorax -Hydrothorax