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• • • • • • • • • LYMPHATICS OF THORAX LEARNING OBJECTIVES At the end of this lecture, the student should be able to : Describe the different groups of lymph nodes in thorax Discuss the deep as well as the superficial lymphatics of thorax LYMPH GLANDS OF THE THORAX may be divided into • Parietal (situated in the thoracic wal) • Visceral (in relation to the viscera) The parietal lymph glands include • Sternal • Intercostal • Diaphragmatic The visceral lymph glands include • Anterior mediastinal • Posterior mediastinal • Tracheobronchial. THE STERNAL GLANDS (internal mammary glands) are placed – at the anterior ends of the intercostal spaces – by the side of the internal mammary artery They derive afferents from – the mamma – from the deeper structures of the anterior abdominal wall above the level of the umbilicus – from the upper surface of the liver through a small group of glands which lie behind the xiphoid process – from the deeper parts of the anterior portion of the thoracic wall Their efferents usually unite to form a single trunk on either side – at right side may open • into the junction of the internal jugular and subclavian veins • or the right subclavian trunk – at left side • the thoracic duct THE INTERCOSTAL GLANDS Occupy – the posterior parts of the intercostal spaces – In relation to the intercostal vessels They derive afferents from – The postero lateral aspect of the chest The efferents of the glands – In the lower four or five spaces unite to form a trunk, which descends and opens either into the • Cisterna chyli • Commencement of the thoracic duct – In the upper spaces • At the left side end in the thoracic duct • At right side end in the right lymphatic duct. THE DIAPHRAGMATIC GLANDS lie on the thoracic aspect of the diaphragm • • • • • • • • • • • • • • consist of three sets – Anterior – Middle – Posterior The anterior set comprises (a) two or three small glands behind the base of the xiphoid process, which receive afferents from the convex surface of the liver (b) one or two glands on either side near the junction of the seventh rib with its cartilage, which receive lymphatic vessels from the front part of the diaphragm. • The efferent vessels of the anterior set pass to the sternal glands. THE DIAPHRAGMATIC GLANDS The middle set – consists of two or three glands on either side – close to phrenic nerves entering the diaphragm The afferents are • derived from the middle part of the diaphragm • on the right side also from the convex surface of the liver Their efferents pass to the posterior mediastinal glands THE DIAPHRAGMATIC GLANDS The posterior set consists of – few glands – situated on the back of the crura of the diaphragm Connected: – on the one hand with the lumbar glands – on the other with the posterior mediastinal glands. THE SUPERFICIAL LYMPHATIC VESSELS OF THE THORACIC WALL ramify beneath the skin converge to the axillary glands. Those over the Trapezius and Latissimus dorsi – Run forward – Unite to form ten or twelve trunks – End in the subscapular group Those over the pectoral region, including the vessels from the skin covering the peripheral part of the mamma – run backward – end in to the pectoral group Those over the serratus anterior – run upward – end in to the pectoral group near the lateral margin of the sternum – pass inward between the rib cartilages – end in the sternal glands the vessels of opposite sides anastomose across the front of the sternum A few vessels from the upper part of the pectoral region – ascend over the clavicle – End in the supraclavicular group of cervical glands • • • • • • • • THE LYMPHATIC VESSELS OF THE MAMMA originate – in the interlobular spaces – on the walls of the galactophorous ducts a plexus situated beneath the areola, receives lymphatics – from the central part of the gland – from the skin over the central part of the gland – from the areola and nipple Its efferents are pass to the pectoral group of axillary glands. The vessels which drain the medial part of the mamma pierce the thoracic wall and end in the sternal glands THE DEEP LYMPHATIC VESSELS OF THE THORACIC WALL consist of: 1. The lymphatics of the muscles – lie on the ribs – end in the axillary glands (mostly) – from the Pectoralis major pass to the sternal glands(some). 2. The intercostal vessels which drain – the Intercostales – Parietal pleura • the Intercostales externi – run backward – end in the intercostal glands • the Intercostales interni and parietal pleura consist of a single trunk in each space – the upper six open separately into the sternal glands – the lower spaces unite to form a single trunk which terminates in the lowest of the sternal glands THE DEEP LYMPHATIC VESSELS OF THE THORACIC WALL 3. The lymphatic vessels of the diaphragm, – form two plexuses • on thoracic surface • on abdominal surface These plexuses anastomose freely with each other on the thoracic surface – communicates with the lymphatics of the costal and mediastinal parts of the pleura – its efferents consist of three groups: • (a) anterior, passing to the gland which lie near the junction of the seventh rib with its cartilage • (b) middle, to the glands on the esophagus and to those around the termination of the inferior vena cava • (c) posterior, to the glands which surround the aorta at the point where this vessel leaves the thoracic cavity THE VISCERAL LYMPH GLANDS Consist of three groups – Anterior mediastinal – Posterior mediastinal – Tracheobronchial • • • • • • • • • • • • • • The anterior mediastinal glands are placed – In the anterior part of the superior mediastinal cavity – In front of the aortic arch They receive afferents from – The thymus – Pericardium – The sternal glands Their efferents unite with – The tracheobronchial glands, to form • The right and left bronchomediastinal trunks THE VISCERAL LYMPH GLANDS The posterior mediastinal glands – lie behind the pericardium – in relation to the esophagus and descending thoracic aorta Their afferents are derived from – the esophagus – the posterior part of the pericardium – the diaphragm – the convex surface of the liver Their efferents end in – the thoracic duct(mostly) – the tracheobronchial glands(some) THE VISCERAL LYMPH GLANDS The tracheobronchial glands form four main groups (a) Tracheal, on either side of the trachea (b) Bronchial, between the lower part of the trachea and bronchi and between the two bronchi (c) Bronchopulmonary, in the hilus of each lung (d) Pulmonary, in the lung substance, on the larger branches of the bronchi. The afferents drain – The lungs and bronchi – The trachea and the heart Their efferent vessels ascend upon the trachea and unite with efferents of the internal mammary and anterior mediastinal glands to form – Right bronchomediastinal trunks may join the right lymphatic duct – Left bronchomediastinal trunks may join the thoracic duct But more frequently they open independently into the junction of the internal jugular and subclavian veins THE LYMPHATIC VESSELS OF THE THORACIC VISCERA comprise of – The heart and pericardium – Lungs and pleura – Thymus – Esophagus THE LYMPHATIC VESSELS OF THE LUNGS Originate into: – A superficial plexus – A deep plexus The superficial plexus – Placed beneath the pulmonary pleura The deep plexus – – • • Accompanies the branches of the pulmonary vessels and the bronchi In the case of the larger bronchi the deep plexus consists of two net works— • Submucous plexus, beneath the mucous membrane • Peribronchial plexus, outside the walls of the bronchi THE LYMPHATIC VESSELS OF THE PLEURA consist of two sets – Visceral part of membrane – Parietal part The visceral pleura drain into – the superficial efferents of the lung The parietal pleura have three modes of ending (a) those of the costal portion join the lymphatics of the Intercostales interni and so reach the sternal glands (b) those of the diaphragmatic part are drained by the efferents of the diaphragm (c) those of the mediastinal portion terminate in the posterior mediastinal glands REFERENCES Gray’s anatomy for students 2004, -by Richard Drake, Wayne Vogl, Adam W.M. Mitchell Grant's.Atlas.of.Anatomy.12th. Anne M. R. Ager and Arther F. Delly Moore, Keith L. - Clinically Oriented Anatomy, by Keith L. Moore THA NK YOU