ABSTRACT
Introduction 14 Embryology 14 Gross anatomy 14 Pleural cavity 15 Microscopic anatomy 15
Layers of the pleural membrane 15 Mesothelial cells 16 Microvillus and lubricating membrane 17 Blood supply of the pleura 17
Blood supply of the parietal pleura 17 Blood supply of the visceral pleura 18 Shunting and pathological changes with age 18
Innervation 18 Contents of the pleural space 18 Transport across the mesothelial cell and pleura 19 Lymphatics 19
Lymphatic circulation of the visceral pleura 19 Lymphatic circulation of the parietal pleura 19
Pleurolymphatic communication 20 Stomata 20 Membrana cribriformis (the cribriform lamina) 21 Lacuna and lymphatic channels 21 Kapmeier’s foci 22 Crevices or fenestrae 22 Pleurolymphatic communication: Does it exist? 22
Pleuroperitoneal communication and diaphragmatic defects 22
Regional difference 23 Visceral pleura 23 Parietal pleura 23
Resting and reactive mesothelial cell 23 Subclinical alterations and repair of the pleura 23 References24
e precise structure and function of the pleural space is not fully understood. ere is marked interspecies variation in the ultrastructure of the pleura; in humans, the pleural cavities are separated by the mediastinum, whereas other mammals (e.g., mice, American bualo) lack complete separation between the le and right pleurae, allowing free movement of air and uid. e adult elephant is the only mammal that does not possess a pleural cavity-a normal pleural space is present in utero, but in late gestation the parietal pleural is replaced with a dense sheet of connective tissue.1 e pleural space is then obliterated with loose connective tissue, permitting movement of the lung against the chest wall. eories have been advanced as to why the elephant lacks a pleural space,2 but the variations seen between mammals in the structure of the pleural cavity is as yet to be explained.
