Lungs 2022-1 PDF

Lungs and trachea  Trachea  Trachea conducts air from the larynx to the principal bronchi.  C6 (cricoid cartilage)- upper border of T5  12 cm in adults  Located in neck and superior mediastinum  Midline in neck , deviated slightly to right in thorax Trac...

Lungs and trachea  Trachea  Trachea conducts air from the larynx to the principal bronchi.  C6 (cricoid cartilage)- upper border of T5  12 cm in adults  Located in neck and superior mediastinum  Midline in neck , deviated slightly to right in thorax Trachea  The lowest cartilaginous ring at the bifurcation of trachea is thick and broad at the central part.  Its lower margin is called carina,  Sharp sagittal ridge at the tracheal bufircation during bronchoscopy.  Trachea Upper ends moves with larynx and lower end moves with respiration. During deep inspiration tracheal bifurcation may descend to T6 15-20 c-shaped cartilaginous rings. Trachealis smooth muscle at the posterior aspect Soft posterior wall allows expansion of the esophagus during swallowing. Carina  a useful landmark  25 cm from insicor teeth, 30cm from external nares  If tracheabronchial LN in the angle between principal bronchi enlarge (due to cancer) carina becomes distorted and flattened. Cervical Part Anterior relations: – Skin, fascia (superficial, investing and pretracheal layers of deep fascia) – Strenohyoid and sternothyroid muscles – Isthmus of the thyroid gland at 2nd to 4th tracheal rings. – Inferior thyroid vein – A. throidea ima – Brachiocephalic artery – Pretracheal LN Posterior – Esophagus – Recurrent laryngeal nerve Lateral – Lobes of thyroid gland – Common carotid artery in carotid sheath – Inferior thyroid arteries  Thoracic Part Anteriorly – Arch of aorta and brachiocephalic and left common carotid – Left brachiocephalic vein – thymus – deep cardiac plexus and tracheabronchial LN (At the bifurcation) Posteriorly – Esophagus – Left recurrent laryngeal nerve  On the left side – Arch of aorta – Left common carotid – Left subclavian a. – Left recurrent laryngeal nerve – Pleura On the right side – Right lung and pleura – Right brachiocephalic vein – Superior vena cava – Azygos arch – Right vagus nerve – Pleura Principal Bronchi  Right (main) bronchus is wider, shorter and more vertical than the left.  2.5cm  Superior lobar bronchus (Before entering the hilum of right lung)  Middle and Inferior lobar bronchus ( on entering the hilum)  Left principal bronchus narrower, longer, more horizantal 5cm below arch of aorta, in front of esophagus Superior and Inferior lobar bronchus Each principal bronchus divides into segmental bronchi. Trachea  Blood Supply; Inferior thyroid artery, brochial arteries at the thoracic part.  Tracheal veins drain into inferior thyroid vein.  Lymph ; pretracheal, paratracheal and tracheobronchial LN  Nerve; vagus, recurrent laryngeal nerves and sympathetic trunks  Pleurae  Each lung is invested and enclosed in a serous pleural sac.  Parietal Pleura- lines thoracic wall, mediastinum, thoracic surface of the diaphragm and extends into the root of the neck.  Visceral Pleura- completely covers the lung and extends into interlobar fissures  Pleural cavity (space)  Pleural cavity- potential space between visceral and parietal pleura  Pleural fluid- a capillary layer of serous fluid which lubricates the pleural surfaces and allows the layers of pleura to slide smoothly over each other during respiration.  Parietal Pleura Costal pleura-covers internal surface of thoracic wall Mediastinal pleura -covers lateral aspects of mediastinum Diaphragmatic pleura - covers thoracic surface of diaphragm on each side of the mediastinum Cervical pleura (pleural cupula)- extends through the superior thoracic aperture into the root of the neck, forming a cup-shaped dome over the apex of lung. – The summit of the cervical pleura is 2-3 cm superior to the level of the medial third of the clavicle at the level of the neck of the 1st rib.  Parietal pleura sensitive to pain, temperature, touch,pressure  Costal pleura- intercostal nerves  Mediastinal pleura- phrenic nerve  Diaphraghmatic pleura- domes by phrenic, periphery by lower 6 intercostal nerves  Visceral Pleura- sensitive to stretch, pulmonary plexus  Lines of pleural reflection The parietal pleura changes direction from one wall to another; – Sternal line of pleural reflection – Costal line of pleural reflection – Vertebral line of pleural reflection  Recesses The lungs donot completely occupy the pleural cavities during expiration; true / fasle Costodiaphramatic recess- lowermost part of costal pleura and peripheral diaphragmatic pleura Costomediastinal recess-smaller recesses posterior to the sternum where the costal pleura is in contact with the mediastinal pleura. Inferior borders of the lungs move further into the pleural cavities.  Pulmonary Ligament  At the root of the lung the visceral and parietal pleural layers are continous; a double layer of parietal pleura hangs inferiorly from this region. imp true or false  Lungs  Each lung lies free in its own pleural cavity, attached to the mediastinum only by root of the lung and pulmonary ligament  Grayish black in adults, Pink in children perital pluera is not continous in the mediastimu, Lungs  Weight of left lung is 550, right 600.  The right lung is broader and shorter than left because liver pushes the dome of diaphragm upwards.  3 lobes of right lung ( upper, middle, lower) – oblique and horizantal fissures  2 lobes of left lung ( upper and lower)-oblique fissure  Oblique fissure;  lateral to T3,  5th rib in the midaxillary line,  7-8 cm lateral to 6th costal cartilage (6th costachondral junction)  Horizantal fissure;  right 4th intercostal cartilage and rib meet the oblique fissure in the midaxillary line Lung has  Rounded apex  Costal,diaphragmatic and mediastinal surfaces  Anterior, inferior and posterior borders  Apex; blunt superior end of the lung ascending above the level of the 1st rib into the neck covered by cervical pleura Surfaces of the lung  Costal surface- adjacent to the sternum, costal cartilages and ribs  Diaphgramatic surface- resting on the dome of diaphgram  Mediastinal surface bears the hilum. Medially related to the mediastinum and posteriorly to the sides of vertebrae Mediastinal surface of the right lung  Right lung- cadiac impression in front and below the hilum  Impression for right atrium and ventricle  Groove for superior vena cava  Groove for brachiocephalic vein- continuation of groove for SVC  Groove for arch of azygos vein-above hilum  Groove for esophagus- behind the trachea,hilum and pulmonary ligament  Impression for IVC  Groove for 1st rib  Area for trachea  Phrenic nerve desecends in front of hilum  Vagus nerve above the hilum, posterior to groove for SVC Mediastinal surface of the left lung  Large cardiac impression in front and below the hilum  Left ventricle  Area for infundibulum of right ventricle  Pulmonary trunk lies in front of hilum  Groove for arch of aorta  Groove for descending aorta  Hilum  T5-T7  Vein Artery Bronchus  Right lung:  Bronchus  Pulmonary artery  Bronchus  Pulmonary vein  Left lung:  Pulmonary artery  Principal bronchus  Pulmonary vein  Apex  Covered by the dome of the cervical pleura  Suprapleural membrane (Sibson’s fascia) protects the apex and the covering pleura in the root of the neck  Fascia derived mainly from endothoracic fascia, scalenus minimus.  Relations of The Apex  Posteriorly- sympathetic chain  Horner Syndrome Pancoast Tumor and Horner's Syndrome A Pancoast tumor is a type of lung cancer that occurs at the apex (top) of the lung. These tumors are also known as superior sulcus tumors. Due to their location, they can invade nearby structures including nerves, blood vessels, and lymphatics. Pancoast tumors can directly invade or compress the sympathetic trunk or the stellate ganglion (a collection of nerves in the lower part of the neck) as they grow. Borders of the lung  Sharp anterior border seperates the mediastinal and costal surfaces. Overlaps the heart, on the left cardiac notch is found,  Round posterior border seperates the mediastinal and costal surfaces. Lies besides the vertebral column.  Inferior border seperates the diaphragmatic surface and other two surfaces.  Left lung has cardiac notch and a lingula below it. Anterior Border of the Right Lung  Between the level of the 2nd and 4th cartilages, its anterior border is near the median plane.  Inferior to the 4th costal cartilage, gradually diverges leaves the sternum posterior to the 6th costal cartilage.  The Anterior Border of the Left Lung  4th costal cartilage  The anterior border deviates laterally about 2.5 cm lateral to the left edge of the sternum to form the cardiac notch.  It then turns inferiorly and slightly medially to the 6th costal cartilage.  The Inferior Borders of the Lungs  6th rib at the midclavicular line, the 8th rib in the midaxillary line and the 10th rib in the midscapular line.  These borders end about 2.5 cm lateral to the spinous process of T10 vertebra.  They lie two ribs superior to the pleura on each of three vertical lines just mentioned.  Charachteristics of Bronchopulmunory Segment  A subdivision of a lung lobe  Pyramidal in shape, apex toward the root of the lung,base at pleural surface  Surrounded by connective tissue  Has segmental bronchus,segmental artery, lymph vessels, and autonomic nerves  Segmental vein lies in the connective tissue between adjacent bronchopulmunary segments  A diseased segment can be removed surgically  Bronchopulmonary Segment  Anatomical, functional, and surgical units of the lungs  Lobar bronchus-segmental bronchus-lobular-terminal bronchiole–respiratory bronchiole-alveolar duct-alveolar sac-alveolus Bronchopulmunory Segments  Right Lung  Superior Lobe  (1) Apical (2) Posterior (3)Anterior  Middle Lobe  (4) Lateral (5) Medial  Inferior Lobe  (6) Superior(apical) (7)medial basal (8) anterior basal (9) lateral basal (10) posterior basal  Left Lung  Superior Lobe  (1) Apical (2) Posterior (3)Anterior (4) Superior lingular (5) Inferior lingular  Inferior Lobe  (6) Superior(apical) (7)medial basal (8) anterior basal (9) lateral basal (10) posterior basal  Auscultation Sites  Apex- medial 1/3 of the clavicle anteriorly and upper part of the supraclavicular region posteriorly  Superior lobe of right lung- clavicle to 4th costal cartilage  Superior lobe of left lung-clavicle to 6th costal cartilage  Auscultation Sites  Middle lobe-4th-6th ribs in front of the midaxillary line  Apical or superior segment of lower lobe - posteriorly in the interval between medial border of scapula and the vertebral spines  Basal segment of the lower lobe-posteriorly in the infrascapular region up to 10th rib. Blood Supply  Bronchial artery- the bronchi, connective tissue of the lung and visceral pleura  Bronchial vein-drain int azygos and hemiazygos veins  Lymph drainage  Superficial and deep plexuses  Not present at the alveolar walls  Superficial plexus lies beneath the visceral pleura and drains over the surface of the lung toward hilum.- bronchopulmonary LN  Deep plexus travels along the bronchi and pulmonary vessels toward the hilum of the lung, pass through the pulmonary nodes within the lung substance- bronchopulmonary LN  Tracheobronchial LN-bronchomediastinal lymph trunks  Pulmonary plexus  Sympathetic and parasympathetic fibers  Symphatetic- efferents- bronchodilatation and vasoconstriction  Parasympathetic fibers bronchoconstriction, vasodilatation,increased glandular secretion  Afferent impulses from bronchial mucus membrane and from strech receptors in the alveolar walls Sym &P/S