Done By : Rahmeh Alsukkar Date : 26 /10/2017
slide 23 The lobes in the right and left lungs are divided into segments,which called bronchopulmonary segments Each segmental bronchus passes to a structurally and functionally independent unit of a lung lobe called a bronchopulmonary segment, It is a subdivision of a lung lobe, It is pyramid shaped (take the external shape of the lung ), with its apex toward the lung root, It is surrounded by connective tissue, It has a segmental bronchus, a segmental artery, lymph vessels, and autonomic nerves, The segmental vein lies in the connective tissue between adjacent bronchopulmonary segments, and Because it is a structural unit, a diseased segment can be removed surgically. **if we make an excision for any segment the other segments still work and intact. each lobe is almost a structural unit but the bronchopulmonary segments are structural and fuctional units which they are a separate entity of lung. The surrounding connentive tissue enhance the elasticity. slide 24 Numb of segmental bronchioles equale numb of bronchopulmonary segments. Each lung has 10 segments. "حفظ" ** the name of each segment is imp Right lung *Superior lobe: Apical, posterior, anterior *Middle lobe: Lateral, medial *Inferior lobe: Superior (apical), medial basal, anterior basal, lateral basal, posterior basal Left lung *Superior lobe: Apical, posterior, anterior, superior lingular, inferior lingular Inferior lobe: Superior (apical), medial basal, anterior basal, lateral basal, posterior basal * slide 25 Lobules wrapped in elastic connective tissue and contains a lymphatic vessel, arteriole, venule and branch from terminal bronchiole. slide26 Blood supply of the lungs : The bronchi, the connective tissue of the lung, and the visceral pleura receive their blood supply from the bronchial arteries, which are branches of the descending aorta. The bronchial veins (which communicate with the pulmonary veins) drain into the azygos and hemiazygos veins. " this is for the cell in the lung not for gaseous exchange (the systemic circulation )" **Remember that the bronchial areteres also supply inferior part of trachea, bronchial tree and lungs. for the gaseous exchange ->> The alveoli receive deoxygenated blood from the terminal branches of the pulmonary arteries. The oxygenated blood leaving the alveolar capillaries drains into the
tributaries of the pulmonary veins, which follow the intersegmental connective tissue septa to the lung root. Two pulmonary veins leave each lung root to empty into the left atrium of the heart. slide 27 lymph drainage : Lymph Drainage of the Lungs The lymph vessels originate in superficial and deep plexuses, they are not present in the alveolar walls. The superficial (subpleural) plexus lies beneath the visceral pleura and drains over the surface of the lung toward the hilum, where the lymph vessels enter the bronchopulmonary nodes. The deep plexus travels along the bronchi and pulmonary vessels toward the hilum of the lung, passing through pulmonary nodes located within the lung substance; the lymph then enters the bronchopulmonary nodes in the hilum of the lung. All the lymph from the lung leaves the hilum and drains into the tracheobronchial nodes and then into the bronchomediastinal lymph trunks, and eventually each trunk the right and left one drains into right and left lymphatic ducts. slide 28 Innervation of lungs : Nerve Supply of the Lungs At the root of each lung is a pulmonary plexus composed of efferent and afferent autonomic nerve fibers. The plexus is formed from branches of the sympathetic trunk (T1-T4 or T5 ) and receives parasympathetic fibers from the vagus nerve. The sympathetic efferent fibers produce bronchodilatation and vasoconstriction. The parasympathetic efferent fibers produce bronchoconstriction, vasodilatation, and increased glandular secretion. note that the afferent is sympathetic and parasympathetic but mostly is the sympathetic so most of the afferent return back with sympathetic and enter the T1 to T5 of the dorsal root of ganglia so the referral pain in lung is mostly with the distribution from T1 to T5 spinal nerve. ** T1 and T2 supply part of shoulder, medial part of the upper limbs and the intercostals spaces. slide 29 Mediastinum Mediastinum is a part of the thoracic cavity,it is directly attach to the cervical region through superior thoracic aperture. it contains It contains the remains of the thymus, the heart and large blood vessels, the trachea and esophagus, the thoracic duct and lymph nodes, the vagus and phrenic nerves, and the sympathetic trunks, So it is very well protected extends extends anteriorly to the sternum and posteriorly to the vertebral column. It is divided into superior and inferior mediastinum by an imaginary plane passing from the sternal angle anteriorly to the lower border of the body of the 4th thoracic vertebra posteriorly. The inferior mediastinum is further subdivided into the middle mediastinum, which consists of the pericardium and heart; the anterior mediastinum, which is a space between the pericardium and the sternum; and the posterior mediastinum, which lies between the pericardium and the vertebral column. ** note that any structure found above the carina of trachea are in the superior mediastinum and the structures below it are in the inferior mediastinum. slide 30
in the med line of the superior mediastinum from posterior to anterior : vertebral column > esophagus > trachea > thymus gland in the para lateral of the superior mediastinum the right side is slightly different from left side in the para lateral from posterior to anterior also from lateral to the medial : the most posterior structure is the sympathetic trunks > azygous,hemi azygous and accessory azygous > thoracic duct" in the left side only" > root of the lungs > major branches areteies and viens " generally the veins more anterior to the arteries " so the most anteriorly is the brachiocephalic vien and superior vena cava posterior to these veins "but still anteriorly to the structures that are mentioned above " is the arch of the aorta and its major branches " brachiocephalic in the right and common carotid and supclavian on the left side " **note :the shape of the posterior wall of the mediastinum result from the protrusion of the vertberal body anteriorly while laterally there is an depressed area "arch like structure " due to the ribs The ascending aorta in the anterior mediastenum. The phrenic and vagi nerves in superior mediastinum: Right vagus nerve runs parallel to the trachea and passes posteriorly to the superior vena cava and the right primary bronchus. Left vagus nerve enters the superior mediastinum between the left common carotid and the left subclavian arteries. It descends anteriorly to the aortic arch, before travelling posterior to the left bronchus. The left recurrent laryngeal nerve arises from the left vagus nerve as it passes the aortic arch **the phrenic and vagi nerves run in the superior mediastinum slightly separate from each other, the vagus runs anterior to the phrenic nerve, but when they reach the root of the lung (or the arch of the aorta ) they are completely separate from each other and the phrenic nerve become anterolateral while the vagus run posteriorly. (look to the picture below )
the internal thoracic artery It originates as a branch of first part of subclavian artery in the neck. After its origin, it descends vertically over the pleura behind the costal cartilages and a fingerbreadth lateral to the sternum, It ends in the sixth intercostals space by dividing into superior epigastric and musculophrenic arteries. Musculophrenic with internal thoracic will give us the anterior inter costal arteries. posterior mediastinum : esophagus almost to the right while descending aorta in the left side as we go downward the esophagus become anteriorly to the left to pass from esophagus opening and the descending aorta become posteriorly and in the right (looking to the picture below ) the vagi nerves as we said they run posterior to the root of the lung to complete in the posterior mediastinum and they will exit from the esophageal opening with the esophagus (as a part of the adventia of the esophagus ) ** the vagi nerves are adherent to the wall of the esophagus so to stimulate it we make a shock for the esophagus using an electrode so the vagi automatically stimulated
anterior mediastinum : thymus, ascending aorta, pulmonary trunk, phrenic nerves **the phrenic nerves as we said they will pass antero laterally one of them on the left and the other in the right side to supply the doom of diaphragm. slide 32 ascending aorta and the relation with pulmonary trunk : the pulmonary trunk leaves the right ventricle of the heart and runs upward,backward an to the left and terminate in the concavity of the aortic arch by dividing into R and L pulmonary arteries slide 33 arch of the aorta : the arch loops around the primary left bronchus ( the trachea divided into right and left bronchus, the left one pass under the arch of aorta ) slide 34 the descending aorta also in relation with the left primary bronchus ( the descending posterior to left bronchus ) slide 35: important picture that summarize the relations mentioned previously ** the pulmonary trunk posterior to the ascending aorta while it is anterior to the descending
aorta. the arch of the aorta superior to the pulmonary trunk and the primary left bronchus. look to slide 37 in slide 36 note that the azygous vein on the right while the hemi azygous in the left side, the azygous vein continue to the superior vena cava through the arch of the azygous and leave an impression on the lung. slide 38 "very imp " ** note the relation between phrenic nerve and vagus nerve again : at the first the phrenic nerve is posteriorly because it is come from cervical plexus while the vagus come from the carotid sheath anteriorly then as we said in root of the lung the phrenic become anterolaterally and the vagus posteriorly slide 39 The apex of lungs protrude in the cervical region " the first third part of the clavicle is the level of the apex " The lungs also the pleura **the anterior border of R and L one lies with lateral border of the sternum, except in the left side where there is cardiac notch which begin in the 4 th ribs "in the 4tb rib there is a deviation due to the presence of the heart (cardiac notch) " **the lower border or " the end of the lungs" : anteriorly "or in the mid clavecular line" it is in the 6 th ribs and laterally "or mid axillary line " in the 8 th ribs while posteriorly "in side of vertebral column " in the level f 10 th ribs. **the posterior border : parallels to the vertebral column. we have oblique and horizontal fissures : the oblique fissure especially anteriorly runs with the 6 th rib and posteriorly leave it and go up ward to reach the 3 rd spinous process where it is end here The horizontal fissure runs with the 4 th ribs until it become vertical laterally with the oblique fissure. if we can localize the site of fissure we can determine the site of lobes, and this is important in asculation process the pleura has thw same borders the as the lung except for the lower border ( anteriorly in the 8 th ribs and laterally in the 10 th rib while posteriorly in the 12 th ribs ) so the different from the lung is 2 intercostal spaces and this due to the presence of costodiaphragmatic recess