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THORACIC CAVITY (cavitas thoracis)
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| THORACIC CAVITY (cavitas thoracis)
is the space limited by the internal surface of thoracic cage in front, on the side, from behind, and by diaphragm from below. Сavity walls are covered with endothoracic fascia. There are 2 pleural sacs and mediastinum, in the thoracic cavity. PLEURA External, parietal pleura covers thoracic cavity inside and attaches to endothoracic fascia. Parietal pleura is divided into 3 parts: costal pleura (pleura costalis), diaphragmatic pleura (pleura diaphragmatica) and mediastinal pleura (pleura mediastinalis). At the root of the lung parietal mediastinal pleura goes into abdominal pleura which joins with lung parenchyma and coveres it from all sides. There is pleural cavity between parietal pleura and visceral pleura. It's a very small slot filled with serous fluid (20 ml) which eases pleural rub while breathing. So, naturally pleural cavity almost does not exist. But in lung collapse, inflammatory processes, the volume of cavity can inerease and reach big size. The upper part of pleural sac which protrudes above 22 thoracic cavity into the triangle of the neck and covers the top of lungs is called cervical pleura. Syntopy of cervical pleura: ● posteriorly – a. vertebralis, ganglion cervicale inferior and ductus thoracicus from the (left), head and neck of 1st rib (caput costae) and m. longus colli are covered with prevertebral fascia to which the cervical pleura is fixed by lig. transversopleurale (from the transverse process of VII cervical vertebra to the cervical pleura), lig. vertebropleurale (from the anterior surface of 1st thoracic vertebra to the posterior surface of cervical pleura). These ligaments are crossed for mobilization of upper part of lungs; ● outside and anteriorly – mm. scaleni; ● outside – brachial plexus; ● inside from the right – truncus brachiocephalicus; ● inside from the left – a. carotis communis sinistra; ● in front and on the top – a. subclavia; ● in front – v. subclavia; ● posteriorly and outside – trachea and esophagus. Costal part of pleura adheres to the endothoracic fascia and is separated from it by the layer of subpleural cellular tissue. It is mostly developed in the posterior parts of spinal column and easily separates together with pleural sac in case of urgent access to the organs of posterior mediastinum. In the anterior division subpleural tissue is very thin and it's almost impossible to separate it from endothoracic fascia. Mediastinal part of parietal pleura in the inferior frontal part attaches to the pericard with which it is bound with poorly marked tissue. There is phrenic nerve with a. et vv. pericardiacophrenicae in the tissue. The anterior edge of pleura is the transition line of costal жүктеу/скачать 2,76 Mb. Достарыңызбен бөлісу:
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