2Lung Anatomy (1) aortic arch (2) pulmonary trunk (3) left atrial appendage(4) left ventricle(5) right atrium(6) superior vena cava(7 & 8) diaphragm(9) transverse fissureTransverse fissure – 6th rib laterallyDoes not estend beyond pulm artery mediallyVisible in 50%
3Lung Anatomy (1) oblique fissure (2) transverse fissure (3) retrocardiac space(4) retrosternal spaceOblique fissure from t4 posteriorlyPropeller shapedDifferentiation between sides- left is more vertical, has more posterior junction with the diaphragm= does not intersect transverse fissureLeft diaphragm is lower and possesses stomach bubble by 2.5cm in 94% population
6Silhouette SignIf two soft tissue densities lie in apposition, then they will not be visible separatelyIf they are separated by air, the boundaries of both will be seen
7Uses of Silhouette Localisation without a lateral view Loss of clarity of a structure suggests there is adjacent soft tissue shadowing even when the abnormality itself is not clearly visualised. This is particularly valuable in some cases of lobar collapse.
8Lobar Collapse Partial or complete loss of lung volume Air resorption Atelectasis
9Common causes of lobar collapse Proximal stenosing bronchogenic carcinoma.Middle aged or elderly, almost always smokers.Asthma due to mucous pluggingYoung adult or older child ,responds to physiotherapy.Inhaled foreign bodyInfants , such as a peanut.Retention of secretionsAny age, frequent cause of post operative collapse.VentilationEndotracheal tube is inserted too far, entering one main bronchus and occluding the other.
10Signs of Lobar Collapse Shift of fissuresCrowding of vessels (increased opacity)Extra lobarHemi diaphragm elevationMediastinal shift towards side of collapseHilar shift and distortionCompensatory hyperinflationRib approximationShift of other structures e.g. granuloma
11Right upper lobe collapse Minor fissure pivots and bowsRight hilar elevationMay simulate mediastinal wideningDeviation of tracheaBoth fissures concave superiorly