MEDIASTINUM — Lateral Cross-Section

Draw this: sagittal view, patient facing left. Sternum front, spine back.
STERNUM (front) Thoracic inlet (T1) SPINE (back) T1 T2 T3 T4 T12 DIAPHRAGM ——— T4 / Sternal Angle (Angle of Louis) ——— SUPERIOR THYMUS (anterior) AORTIC ARCH Brachio- cephalic L Carotid L Subcl SVC TRACHEA ESOPHAGUS L RLN hooks under arch Thoracic duct ANT Thymic remnant Fat Lymph nodes MASSES: 4 T's Thymoma Teratoma T.Lymphoma Thymoma→MG MIDDLE HEART Asc. Aorta Pulm trunk Carina Phrenic N. (on pericardium) 🇮🇳 TB nodes = #1 middle mass POST Desc. Aorta Esophagus ← LA compresses (RHD→MS) Thoracic duct Azygos vein Sympath chain Vagus→esoph plexus Mass: Neurogenic Sternum→Pericardium = Pericardium + contents Pericardium→Spine COMPRESSION SYNDROMES — Draw as Table Compressed Syndrome Key Features Cause SVC SVC Syndrome Face edema, neck veins, Pemberton's Lung Ca (small cell) L RLN Ortner's (if RHD) Hoarseness (L>R), bovine cough Lung Ca / 🇮🇳RHD→MS Phrenic Phrenic palsy Raised hemidiaphragm, sniff test Tumor / cardiac surgery Sympath chain Horner's Miosis, ptosis, anhydrosis (ipsi) Pancoast tumor Esophagus Dysphagia Dysphagia lusoria / LA compression 🇮🇳 RHD→MS→large LA ANT = 4 T's | MID = Heart + TB nodes (India) | POST = Nerves | L RLN hooks under aortic arch
🧠 5 RETENTION ANCHORS:
1. T4 (sternal angle) splits superior from inferior. Draw a horizontal line first — everything above is superior.
2. Anterior = space between sternum and pericardium. Masses = 4 T's. Thymoma→MG (30-50%).
3. Middle = the pericardial sac itself + contents. Phrenic nerve runs ON pericardium. TB nodes #1 in India.
4. Posterior = pericardium to spine. Desc aorta, esophagus, thoracic duct, azygos, sympathetic chain. Neurogenic masses.
5. RHD→MS→large LA = three compressions from one disease: esophagus (dysphagia), L RLN (Ortner's), L bronchus (collapse).