TRACHEA Pars cervicalis and pars thoracica Bifurcatio tracheae (T4) - bronchus principalis dexter et sinister Carina tracheae The isthmus glandulae thyroideae - in contact with the 2^nd and 3^rd tracheal cartilages Vv. thyroideae inf. - below the isthmus. The sides of the trachea - lobes of the thyroid gland. Paratracheal space - A. carotis com., v. jugularis int. and n. vagus run Oesophagus – posteriorly N. laryngeus recurrens - in the groove between the trachea and oesophagus. Nodi lymphatici tracheobronchiales 15 – 20 hyaline cartilages (cartilagines tracheales) connected by ligg. anularia paries membranaceus glandulae tracheales Tracheotomy The incision is commonly made through the second and third tracheal rings. As the isthmus of the thyroid gland covers the 2^nd and 3^rd tracheal rings, it is retracted inferiorly (tracheotomia superior) or incision is performed through lower tracheal rings (tracheotomia inferior). During the inferior tracheotomy, the following anatomical facts must be kept in mind to avoid possible damage to important structures:1) the inferior thyroid veins form a plexus anterior to the trachea; 2) a small a. thyroidea ima is present in about 10% of people and ascends to the inferior border of the isthmus; 3) the left brachiocephalic vein, jugular venous arch , and the pleurae may be encountered, particularly in children; 4) the thymus covers the inferior part of the trachea in infants. Tracheostomy, when the duration of endotracheal intubation is expected to be longer than 72 hours. THYROID GLAND Lobus, dexter, sinister, isthmus (lobus pyramidalis) Capsula propria Fascia externa s. perithyroidea Folliculi - colloid - thyroglobulin (thyroxin, trijodthyronin) PARATHYROID GLANDS (GLANDULAE PARATHYROIDEAE) 2 pairs of small lens-shaped glands may be inserted in the capsule or parenchyma of the thyroid gland. The cranial pair - at the level of the lower margin of the cricoid cartilage; the caudal pair lies at the lower margin of the thyroid gland lobes. parathormone - regulates plasmatic levels of calcium and phosphorus. BRONCHI Arbor bronchialis Bronchi principales dexter et sinister (bifurcatio tracheae) - bronchi lobares (3 right and 2 left) - bronchi segmentales LUNG (PULMO) Basis pulmonis Apex pulmonis - sulcus arteriae subclaviae and the sulcus costae primae Facies diaphragmatica Facies costalis Facies mediastinalis - hilum pulmonis - radix pulmonis. The craniocaudal order of the root structure is different on the right (bronchus, pulmonary artery and veins) than on the left (artery, bronchus, veins). The mediastinal surface of the right lung– sulcus v. cavae sup., sulcus v. azygos, sulcus oesophageus, impressio cardiaca. The mediastinal surface of the left lung - sulcus aorticus, impressio cardiaca, sulcus oesophageus Margo inferior, anterior, posterior Incisura cardiaca - lingula pulmonis sinistri Fissurae interlobares - fissura obliqua, fissura horizontalis - lobus medius BRONCHOPULMONARY SEGMENTS (segmenta bronchopulmonalia) The right lung: segmentum apicale 1, posterius 2, anterius 3 in the superior lobe, segmentum laterale 4 and mediale 5 in the medial lobe, and segmentum apicale 6, basale mediale 7, basale anterius 8, basale laterale 9, basale posterius 10. The left lung: segmentum apicoposterius 1+2, segmentum anterius 3, segmentum lingulare superius 4 and segmentum lingulare inferius 5 in the superior lobe. Segmentum apicale 6, segmentum basale mediale 7 that is variable and often merges with the next segmentum basale anterius 8, basale laterale 9, basale posterius 10. Segmentectomy – lobectomy - pneumonectomy Bronchioli have no cartilages - terminal bronchioli - 2-3 bronchioli respiratorii - ductuli alveolares terminated by atria - sacculi alveolares - alveoli The whole number of alveoli is 300-400 milion and their surface is 50-80 m2. PLEURA Pleura visceralis - pleura costalis, pleura diaphragmatica, pleura mediastinalis Pleura parietalis Lig. pulmonale Cavum pleurae Cupula pleurae Lig. scalenopleurale, vertebropleurale, costopleurale Recessus pleurae Recessus costodiaphragmaticus - deepest - The caudal margin of the lung is inserted in it during inspiration but it does not fill the recess entirely even during the maximal inspiration. Recessus costomediastinalis Recessus phrenicomediastinalis Pneumothorax Borders of the parietal pleura Cupula pleurae projects to the fossa supraclavicularis minor (between both attachments of the sternocleidomastoideus muscle). The ventral border descends from the cupula medially behind the sternum to the level of the 2^nd rib. This triangle demarcates the space for the thymus (area interpleuralis sup. s. thymica). The ventral border then continues from the 2^nd to the 4^th rib (parallel to the opposite ventral border) shifted slightly to the left. The right ventral border then descends to the 6^th sternocostal joint while on the left a convex arch forms the triangular space for the pericardium (area interpleuralis inferior s. pericardiaca) and ends at the 6^th costal cartilage. The caudal border is the same on both sides: from the 6^th rib descends obliquely laterally, in the midclavicular line reaches below the 7^th rib, in the anterior axillary line reaches the lower margin of the 8^th rib, in the middle axillary line the lower margin of the 9^th rib and in the posterior axillary line the lower margin of the 10^th rib. In the scapular line the lower border reaches the 11^th rib and in the paravertebral line it reaches the 12^th costovertebral joint. At the left side it may reach more caudally (the left dome of the diaphragm is lower). Borders of the lungs Apex pulmonis fills the cupula pleurae, it has the same border. The ventral border of both lungs corresponds to the ventral border of the pleura. The lower border projects 1-2 ribs higher than the lower border of the pleura. In the paravertebral line it reaches the 11^th rib. The posterior border projects lateral to the vertebrae from T11 to C7. Mechanics of the respiration The respiration is caused by the volume changes of the lungs induced by movements of the thorax by means of respiratory muscles. Throughout this process the volume of the thorax becomes smaller during expiration and enlarges during inspiration. The diaphragm may be regarded as a piston that during its contraction makes excursions down to enlarge the thorax in craniocaudal direction. The external intercostal muscles enlarge the thorax in the ventrodorsal and transverse direction. The lungs expand due to a decline of pressure in the pleural cavity and adhesion between the visceral and parietal pleurae maintaining by pleural fluid and increase their volume. Air is sucked into the respiratory tract. During expiration the elastic thoracic cage returns to its resting position. The abdominal muscles contract, push to the internal organs and relaxed diaphragm that is pushed upward. Contraction of the internal and intimal intercostals muscles results in the diminution of the ventrodorsal and transverse diameter of the thorax and air is expired. The own elasticity of the lungs also participates in expiration. pericardiacophrenicae and n. phrenicus. The posterior mediastinum contains the oesophagus with the vagal trunks, which lie ventrally and dorsally, descending aorta, thoracic duct, azygos and hemiazygos veins, and sympathetic trunks. THYMUS Lobus dexter et sinister Capsula thymi Lobuli thymi Cortex,medulla thymi