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<\/a>Description<\/h3>\n<\/span>\n\n\nThe two lungs differ in size and shape:<\/p>\n\n\n\n
- The right lung is slightly bigger and heavier<\/li>
- The left lung has a thin part which is between the heart and the great vessels, and the ribs<\/li><\/ul>\n\n\n\n
The positions and projections are described at rest \u2014 between inspiration and expiration.<\/em><\/p>\n\n\n<\/span>\nFissures and lobes<\/h4>\n<\/span>\n\n\n- Both lungs have an oblique fissure <\/strong>running from the head of the 3rd rib to the sternal end of the 6th rib<\/li>
- The right lung also has an additional transverse<\/strong> (horizontal<\/strong>) fissure <\/strong>running along the 4th rib<\/li>
- These fissures divide the lungs into lobes:
- The right lung has three (superior, middle and inferior)<\/li>
- The left has two (superior and inferior).<\/li><\/ul><\/li><\/ul>\n\n\n<\/span>\n
Segments<\/h4>\n<\/span>\n\n\nThere are 10 segments in each lung:<\/strong><\/p>\n\n\n\n- The left lung has 5 in each lobe<\/li>
- The right lung has 3 in the superior, 2 in the middle and 5 in the inferior lobe<\/li><\/ul>\n\n\n<\/span>\n
Poles and surfaces<\/h4>\n<\/span>\n\n\n- Superior<\/strong> \u2014 Apex, covered by cupula pleura<\/strong>, emerging 2cm above the first rib below the scalene muscles (Kronig\u2019s space<\/strong>)<\/li>
- Inferior<\/strong> \u2014 Base, resting on the diaphragm<\/li>
- Lateral<\/strong> \u2014 Costal surface<\/li>
- Medial<\/strong> \u2014 Containing the root, facing the mediastinum and pericardium<\/li><\/ul>\n\n\n<\/span>\n
Projections of the lungs<\/h4>\n<\/span>\n\n\n- Superior <\/strong>(apex) \u2014 At the level of the spinous process of the C7 vertebra, 2.5 cm from the midline<\/li>
- Inferior<\/strong>
- Midclavicular line <\/strong>\u2014 Crosses the 6th rib<\/li>
- Anterior axillary line<\/strong> \u2014 Crosses the 7th rib<\/li>
- Midaxillary line<\/strong> \u2014 Crosses the 8th rib<\/li>
- Scapular<\/strong> and paravertebral lines<\/strong> \u2014 Crosses and the 9th rib<\/li><\/ul><\/li>
- Medial <\/strong>\u2014 Moving down and medially from the apex, starting posterior to the sternal angle:
- Right lung <\/strong>\u2014 Approaches the midline, extending until the 6th rib along the edge of the sternum, or slightly medial to it<\/li>
- Left lung <\/strong>\u2014 Approaches the midline (not as close to as the right lung), extending to the 4th costal cartilage along the sternal margin.
From there, it deviates sharply to the left at the cardiac notch but does not reach the midclavicular line (stays medial to it by 2 cm), turns right, so the apex of the lingula is located at the cartilage of the 6th rib<\/li><\/ul><\/li><\/ul>\n\n\n<\/span>\nThe lung hilum<\/h4>\n<\/span>\n\n\n- The hilum<\/strong> of the lung surrounds its root, which contains arteries, veins, and the main bronchus.<\/li>
- The order of structures in the hilum is the following
- Anterior-to-posterior \u2014 VAB<\/strong> (both lungs)<\/li>
- Superior-to-inferior \u2013 ABV<\/strong> (left lung), BAV<\/strong> (right lung)<\/li><\/ul><\/li><\/ul>\n\n\n\n
Where\u00a0A<\/strong>\u00a0= artery,\u00a0B<\/strong>\u00a0= bronchus,\u00a0V<\/strong>\u00a0= vein. The anterior-to-posterior order is almost always the same, but the superior-to-inferior order might change.<\/p>\n\n\n\nThere are several other structures that are not always clearly visible in the specimens:<\/p>\n\n\n\n
- Small arteries \u2014 Bronchial arteries<\/strong> \u2014 when found, they are clearly distinguishable from other blood vessels (more information below)<\/li>
- Lymph nodes<\/li>
- Nerve fibers<\/li><\/ol>\n\n\n<\/span>\n
Exam tip<\/h4>\n<\/span>\n\n\nDuring your practical exam, you might be asked to identify the structures in the hilum of a lung specimen.<\/p>\n\n\n\n
- First of all, identify which lung you are holding<\/strong>. The easiest way to tell is by the number of fissures (single fissure = left, two fissures = right)<\/li>
- Orient yourself regarding poles and surfaces. The apex is at the top, the base is at the bottom, and the root is oriented towards the midline of the body<\/li>
- Apply and keep the principles described above in your mind<\/li>
- To confirm your answer, palpate the structures. The bronchus is very rigid due to the cartilage, and the artery has a slightly thicker and more elastic wall than the vein<\/li><\/ol>\n\n\n\n
You can, of course, skip the first three steps and do the fourth one right away, but your examiner won\u2019t always let you touch the specimen before you verbally explain your steps.<\/p>\n\n\n\n
In some cases, an examiner might try to confuse you by pulling out a small, elongated blood vessel from the root of the lung. These are the most likely bronchial arteries.<\/p>\n\n\n\n
The positions and projections are described at rest \u2014 between inspiration and expiration.<\/em><\/p>\n\n\n<\/span>\n There are 10 segments in each lung:<\/strong><\/p>\n\n\n\n Where\u00a0A<\/strong>\u00a0= artery,\u00a0B<\/strong>\u00a0= bronchus,\u00a0V<\/strong>\u00a0= vein. The anterior-to-posterior order is almost always the same, but the superior-to-inferior order might change.<\/p>\n\n\n\n There are several other structures that are not always clearly visible in the specimens:<\/p>\n\n\n\n During your practical exam, you might be asked to identify the structures in the hilum of a lung specimen.<\/p>\n\n\n\n You can, of course, skip the first three steps and do the fourth one right away, but your examiner won\u2019t always let you touch the specimen before you verbally explain your steps.<\/p>\n\n\n\n In some cases, an examiner might try to confuse you by pulling out a small, elongated blood vessel from the root of the lung. These are the most likely bronchial arteries.<\/p>\n\n\n\nFissures and lobes<\/h4>\n<\/span>\n\n\n
Segments<\/h4>\n<\/span>\n\n\n
Poles and surfaces<\/h4>\n<\/span>\n\n\n
Projections of the lungs<\/h4>\n<\/span>\n\n\n
From there, it deviates sharply to the left at the cardiac notch but does not reach the midclavicular line (stays medial to it by 2 cm), turns right, so the apex of the lingula is located at the cartilage of the 6th rib<\/li><\/ul><\/li><\/ul>\n\n\n<\/span>\nThe lung hilum<\/h4>\n<\/span>\n\n\n
Exam tip<\/h4>\n<\/span>\n\n\n