Thorax

• Pleurae


  The serous membranes that line the lungs and thoracic cavity
• Pleura


  • Visceral pleura
  • Parietal pleura
• Visceral pleura


  • Covers the lungs
• Parietal pleura


  • Covers the internal surface of the thoracic cavity
• Pleural cuff


  • Surrounds structures near the hilium of the lung
  • Hangs down as a loose fold known as the pulmonary ligament
• Pleural cavity


  The potential space between the parietal and visceral pleura<|>Contains a small volume of serous fluid<|>Provides lubrication<|>Provides surface tension
• Pleural recesses


  • Formed only by the parietal pleura
  • Costodiaphragmatic recess - between the costal and diaphragmatic pleurae
  • Costomediastinal recess - between the mediastinal and costal pleurae
  • Phrenicomediastinal recess - between the mediastinal and diaphragmatic pleurae
• Pleural recesses during inspiration and expiration

  1. Costodiaphragmatic recess - lower margins of the lungs descend into the recess

  2. Costomediastinal recess - anterior borders of the lungs slide in and out of the recess
• Projections of the right lung

  • Anterior border projects 5mm laterally to the pleura from the apex of the 4th rib
  • Extends from the 4th rib to the attachment point of the 6th rib to the sternum
• Projections of the left lung

  • Anterior border projects from the 4th rib and extends beyond the lateral margin of the sternum and pleura to form the cardiac notch