Lungs and Thoracic Cavity

General Remarks and Definitions

contains 2 pleural sacs and the mediastinum (median space between the pleural cavities; contains heart, aorta, trachea, esophagus, etc)

pulmonary or visceral pleura cover each lung

root of the lung is the area of attachment to the mediastinum

parietal pleura (lines wall of pleural cavity) can be subdivided into costal pleura (line rib cage); mediastinal pleura (line mediastinum); diaphragmatic pleura (line diaphragm); cupula or cervical pleura (extending into the neck

pleural reflections are the lines where costal pleura become diaphragmatic and mediastinal

pleural recesses: sites of reflections of parietal pleura

costomediastinal recess is part of left pleural cavity; parietal pleural reflection from the anterior portion of the thoracic wall to the mediastinum

both pleural cavities have costodiaphragmatic reecess located at the most inferior lmits of the parietal pleura

endothoracic fascia: small amount of connective tissue that separates the rib cage from the parietal pleura

the 2 pleural cavities are 2 separate and closed potential spaces

serous lubricant present to reduce friction during respiratory movements

potential space may become a real one Þ pneumothorax (filled with air) or Þ hemothorax (filled with blood)

pleurisy: inflammation of the pleuraeÞ pleural adhesions between parietal and visceral plura

Exploration of Pleural Cavities

pleural sacs: identify right and left

pleural cavities

parietal pleura: costal, diaphragmatic, mediastinal, cupola

costomediastinal recess: left side only; region where heart lies close to anterior thoracic wall

costodiaphragmatic recesses

pleural tap: aspiration of pathological material from the pleural cavity; performed in the midaxillary line or post to it, usually in ICS 6, 7, or 8

study lungs in situ

oblique fissures

horizontal fissures (right lung)

lobes: right (superior, middle, inferior), left (superior, inferior)

pericardial sac (contains heart)

root of lung

root: structures that pass from and to the lung

pulmonary ligament: just inferior to the root of lung; reaches caudally nearly to the diaphragm

Removal of Lung

phrenic nerves: pass anterior to the roots of the lung along sides of pericardial sac

vagus nerves: pass posterior to the roots of the lung

Pleurae

mediastinal pleura

can palpate esophagus to right and descending aorta to left

mesoesophagus: where the 2 pleural layers come together posterior to esophagus and anterior to aorta
the 2 layers pass over the aorta and reach the vertebra where they become costal pleura

intercostal structures

intercostal arteries arise from the aorta and disappears in space between esophagus and vertebral column

intercostal veins

intercostal nerves which will disappear into the innermost intercostal muscle

sympathetic trunk

thoracic part of the sympathetic trunks (chains)

white rami communicates: preganglionic fibers pass through it to the sympathetic ganglia of the chain where they synapse

gray rami communicates: postganglionic fibers pass through it to the peripheral nerves

sympathetic trunk: crosses heads of ribs 2 to 9 and lies on sides of lower thoracic vertebrae

sympathetic ganglia: series of swellings in the sympathetic trunk
two rami (white and gray) communicate with each intercostal nerve and its corresponding sympathetic ganglion

greater splanchnic nerve: largest of the 3 splanchnic nerves

The Lungs

examination of the lungs

right is shorter but more voluminous

apex: top of lung; rises as high as the neck of the 1^st rib

superior and inferior lobe separated by oblique fissure

horizontal fissure of right lung creates a middle lobe

lung surfaces: costal, medial, basal, diaphragmatic

borders are anterior and inferior

contact impressions

mediastinal surface of right lung: cardiac impression and groove for the esophagus

mediastinal surface of left lung: cardiac impression and groove for aortic arch and descending aorta

hilus and related structures

hilus

bronchus, pulmonary artery, and pulmonary veins

bronchus lies posterior, artery superior, and veins inferior

main bronchus

left lung: superior (upper) and inferior (lower) lobar bronchi

right lung: superior, middle, and inferior bronchi

right superior bronchus (eparterial bronchus): higher than any other bronchus, higher than pulmonary artery

segmental bronchi

segmental bronchi

pulmonary artery

specific segmental bronchi and branchopulmonary segments

right lung

superior lobe: apical, posterior, anterior
middle lobe: lateral, medial
inferior lobe: superior, medial basal, anterior basal, lateral basal, posterior basal

left lung

superior lobe: apical-posterior, anterior, superior lingular, inferior lingular
inferior lobe: superior, anterior-medial basal, lateral basal, posterior basal