Thorax

1. Thorax 山东大学医学院 解剖教研室 李振华

2. The muscles of thorax Extrinsic muscles • Pectoralis major • Pectoralis minor • Serratus anterior Intrinsic muscles • Intercostales externi 肋间外肌 • Intercostales interni 肋间内肌 • Intercostales intimi 肋间最内肌 • Transverses thoracis 胸横肌

3. Intercostales externi • Origin: lower border of riⅡ) • Insertion: upper border of rib below origin • Action: elevate ribs adding in forced inspiration • Replaced anteriorly by external intercostals membrane. Intercostales interni • Origin: upper border of rib • Insertion: lower border of rib above origin • Action: depress ribs for forced expiration • Replaced posteriorly by internal intercostals membrane.

4. Diaphragm膈 Shape and position: dome-shaped between thorax and abdomen, consists of a peripheral muscular part and a central tendon Origin • Sternal part: xiphoid process • Costal part: lower six and costal cartilages • Lumbar part: arises by two crura from upper 2-3 lumbar vertebrae • Insertion: central tendon Weak areas: triangular spaces without muscular tissue • Lumbocostal triangle: between costal and lumbar parts. • Sternocostal triangle: between costal and sternal parts.

5. Openings in the diaphragm • Aortic hiatus主动脉裂孔－lies anterior to the body of the 12th thoracic vertebra between the crura. It transmits the aorta, thoracic duct • Esophageal hiatus 食管裂孔－for esophagus and vagus nerves at level of T10. • Vena cava foramen 腔静脉孔－for inferior vena cava, through central tendon at T8 level T8 T10 T12

6. Action: • Contraction: the dome moving downward, increases the volume of thoracic cavity which results in inspiration, at the same time the intra-abdominal pressure is increased assists in defecation, vomiting or child birth. • Relaxation: the dome returns to the former position, reduces the volume to the thoracic cavity, resulting in expiration.

7. Arteries of thorax Pulmonary trunk • Arises from right ventricle • Runs up, back ,and to the left • Bifurcates inferior to aortic arch into right and left pulmonary arteries, one for each lung Pulmonary arteries • Right pulmonary artery－passes posterior to ascending aorta and superior vena cava to hilum of right lung • Left pulmonary artery－passes anterior to descending aorta and left main bronchus to hilum of left lung

8. Arterial ligament动脉韧带－remnant of ductus arteriosus, connects bifurcation of pulmonary trunk to inferior border of aortic arch Triangule of ductus arteriosus 动脉导管三角 • Bounded by phrenic n., left vagus n. and left pulmonary a. • Contents－ arterial ligament , left recurrent n. and superficial cardiac plexuses

9. Ascending aorta 升主动脉 • Runs upward, forward and to the right, • Extends to level of second right sternocostal joint • Branches: right and left coronary arteries

10. Aortic arch 主动脉弓 • Continuation of ascending aorta • Curves upward, to the left and posteriorly, then downward, arching over left principal bronchus and pulmonary trunk to lower border of T4 level, to become descending aorta • Branches (from right to left ) • Brachiocephalic trunk－extends to right sternoclavicular joint, bifurcates into right subclavian and right common carotid arteries • Left common carotid artery • Left subclavian artery • Aortic isthmus－baroreceptor • Aortic glomera－chemoreceptor

11. Thoracic aorta 胸主动脉 • Continuation of aortic arch at lower border of T4 • Courses downward on left side of, then in front of vertebral column • Passes through aortic hiatus of diaphragm at level of T12 vertebra to enter abdominal cavity • Main branches • Parietal branches • Nine pairs posterior intercostals arteries • One pair subcostal artery • For lower nine intercostals spaces and upper part of abdominal wall; superior phrenic arteries supply the superior surface of the diaphragm. • Visceral branches • Bronchial branches: one or two for each lung • Esophageal branches • Pericardial branches

12. Internal thoracic artery 胸廓内动脉－descends into thorax 1.2cm lateral to edge of sternum, and ends at the sixth costal cartilage by dividing musculophrenic and superior epigastric arteries

14. Veins of thorax Brachiocephalic veins • Formed by union of internal jugular and subclavian veins posterior to the sternoclavicular joint • Angle of union is termed venous angle Superior vena cava • Formed by union of right and left brachiocephalic veins behind the right sternocostal synchorndrosis of first rib • Runs vertically down on right of ascending aorta • Joined by azygos vein at level of sternal angle • Enters right atrium at lever of lower border of third right sternocostal joint • Collects blood from veins of upper half of body

15. Azygos vein 奇静脉 • Begins as continuation of right ascending lumbar vein • Ascending along the right side of vertebral column • Joins superior vena cava by aching above right lung root at level of T4 to T5 • Receives right posterior intercostals and subcostal veins plus some of bronchial, esophageal and pericardial veins, and hemiazygos vein • Tributaries－hemiazygosv.半奇静脉and accessory hemiazygos v. 副半奇静脉, which receive most left posterior intercostals vein and left bronchial veins

16. Veins of vertebral column Consists of • External vertebral venous plexus • Internal vertebral venous plexus

17. The lymphatic drainage of thorax The lymphatic drainage of thoracic wall • To axillary lymph nodes • To parasternal lymph nodes (along internal thoracic vessels) • To intercostals lymph nodes from deeper structures

18. lymph nodes of the thoracic contents lymph nodes of trachea, bronchi and lungs • Pulmonary lymph nodes肺淋巴结lie in the angles of bifurcation of branching lobar bronchi • Bronchopulmonary hilar lymph nodes支气管肺门淋巴结－lie in the hilus of the lung • Tracheobronchial lymph nodes气管支气管淋巴结－situated above or below the bifurcation of trachea • Paratracheal lymph nodes 气管旁淋巴结－along each side of the trachea

19. Anterior mediastinal lymph node纵隔前淋巴结 lies anterior to the large blood vessels of thoracic cavity and pericardium; the efferents unite with those of paratracheal lymph nodes, to form the right and left bronchomediastinal trunks 支气管纵隔干. The left bronchomediastinal trunk terminates in thoracic duct, and right in the right lymphtic duct • Posterior mediastinal lymph nodes纵隔后淋巴结 lie along the esophagus and thoracic aorta

20. Thoracic duct胸导管 • Begins in front of L1 as a dilated sac, the cisterna chyli乳糜池, which formed by joining of left and right lumbar trunks and intestinal trunk • Enter thoracic cavity by passing through the aortic hiatus of the diaphragm and ascends along on the front of the vertebral column, between thoracic aorta and azygos vein • Travels upward, veering to the left at the level of T5 • At the roof of the neck, it turns laterally and arches forwards and descends to enter the left venous angle

21. Just before termination, it receives the left jugular, subclavian and bronchomediastinal trunks • Drains lymph from lower limbs, pelvic cavity, abdominal cavity, left side of thorax, and left side of the head, neck and left upper limb Right lymphatic duct右淋巴导管 • Formed by union of right jugular, subclavian, and bronchomediastinal trunks • Ends by entering the right venous angle • Receives lymph from right half of head, neck, thorax and right upper limb

22. Anterior branches of thoracic nerves • Intercostal nerves 肋间神经(anterior rami of T1- T11): runs forward inferiorly to intercostals vessels in costal groove of corresponding rib, between intercostals externi and intercostals interni; first six nerves are distributed within their intercostals space, lower five intercostals nerves leave anterior ends of their intercostals spaces to enter abdominal wall • Subcostal nerve肋下神经 (anterior ramus of T12): follows inferior border of T12 rib and passes into abdominal wall • Distribution: distributed to intercostales and anterolateral abdominal muscles, skin of thoracic and abdominal wall, parietal pleura and peritoneum

23. The segmental innervation of anterior surface of trunk • T2－sternal angle • T4－ nipple • T6－xiphoid process • T8－costal arch • T10－umbilicus • T12－midpoint between umbilicus and symphysis pubis

25. Phrenic nerve膈神经 • Descends over scalenus anterior to enter thorax • Accompanied by pericardiophrenic vessels and passes anterior to lung roots between mediastinal pleura and pericardium to supply motor and sensory innervation to diaphragm • Sensory fibers supply to pleurae, pericardium and peritoneum of diaphragm; usually right phrenic nerve may be distributed on live, gallbladder and biliary system.

26. Left vagus nerve 左迷走神经 • Enter thoracic inlet between left common carotid and left subclavian arteries, posterior to left brachiocephalic vein • Crosses aortic arch where left recurrent laryngeal nerve branches off • Passes posterior to left lung root • Forms anterior esophageal plexus • Forms anterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity , then divides into anterior gastric and hepatic branches

27. Right vagus nerve右迷走神经 • Enter thoracic inlet on right side of trachea • Travels downward posterior to right brachiocephalic vein and superior vena cava • Passes posterior to right lung root • Forms posterior esophageal plexus • Forms posterior vagal trunk at esophageal hiatus where it leaves thorax and passes into abdominal cavity, then divides into posterior gastric and celiac branches

28. Recurrent laryngeal nerves 喉返神经 • Right one hooks around right subclavian artery, left one hooks aortic arch • Both ascend in tracheo-esophageal groove • Nerves enter larynx posterior to cricothyroid joint, the nerve is now called inferior laryngeal nerve • Innervations: laryngeal mucosa below fissure of glottis , all laryngeal laryngeal muscles except cricothyroid Bronchial and esophageal branches

29. Thoracic sympathetic trunk 胸交感干 • Branches of sympathetic trunk to thoracic plexuses • Greater splanchnic nerve 内脏大神经 formed by preganglionic fibers from T5~T9 ganglia, and relay in celiac ganglion. • Lesser splanchnic nerve 内脏小神经 formed by preganglionic fibers from T10~T12 ganglia, and relay in aorticorenal ganglion. • The postganglionic fibers supply the liver, spleen, kidney and alimentary tract as far as the left colic flexure.

30. Regional anatomy of thorax 山东大学医学院 解剖教研室 李振华

31. Parts and regions of the thorax Boundaries • Superior－jugular notch, sternoclavicular joint, superior border of clavicle, acromion, spinous processes of C7 • Inferior－xiphoid process, costal arch, 12th and 11th ribs, vertebra T12 Regions • Thoracic wall • Thoracic cavity

32. Landmarks • Jugular notch corresponds with • The 2th thoracic vertebra in male, the 3th thoracic vertebra in female • Sternal angle connects 2nd costal cartilage laterally， corresponds with • The lower border of 4th thoracic vertebra • The bifurcation of trachea in the adult • The beginning of aortic arch which ends posteriorly at the same level • The esophagus is crossed by the left main bronchus

33. Xiphoid process－phisternal junction lies opposite the body of the 9th thoracic vertebra • Clavicle • Inferior fossa of clavicle • Coracoid process • Ribs and intercostal spaces • Costal arch • Infrasternal angle • Xiphocostal angle • Papillae

34. Thoracic wall • Skin • Superficial fascia • Thoracoepigastric v. • Supraclavicular n. • Anterior and lateral cutaneous branches of intercostal n. • Deep fascia

35. Intercostal space Posterior intercostal v. Posterior intercostal a. Intercostal n.

36. Lymphatic drainage of breast • Into pectoral ln. from lateral and central parts of breast • Into apical and supraclavicular ln. from superior part of breast • Into parasternal ln. from medial part of breast • Into interpectoral ln. from deep part of breast • The lymphatic capillaries of breast form an anastomosing network which is continuous across the midline with that of the opposite side and with that of the abdominal wall

37. Internal thoracic vessels • Internal thoracic a.&v. 胸廓内动脉和静脉 • Parasternal ln. 胸骨旁淋巴结 Endothoracic fascia 胸内筋膜

38. The Mediastinum 纵隔 Concept－all of organs between the left and right mediastinal pleurae is called mediastinum. It extends from the sternum in front to the vertebral column behind, and from the thoracic inlet above to the diaphragm below.

39. Subdivisionsof mediastinum • Superior mediastinum上纵隔 • Inferior mediastinum下纵隔 • Anterior mediastinum 前纵隔 • Middle mediastinum 中纵隔 • Posterior mediastinum 后纵隔

40. Left subclavian a. Thoracic duct Aortic arch Left vagus n. Left recurrent n. Thoracic aorta Phrenic n. & pericardiacophrenic a. Sympathetic trunk Root of lung Pericardium Esophagus Greater splanchnic n Left side of mediastnum

41. Trachea Superior vena cava Left vagus n. Arch of azygos v. Phrenic n. & pericardiacophrenic a. Azygos v. Root of lung Sympathetic trunk Pericardium Esophagus Inferior vena cava Right side of mediastnum

42. Superior mediastinum 上纵隔 Locating－from inlet of thorax to plane extending from level of sternal angle anteriorly to lower border of T4 vertebra posterioly Contents • Superficial layer • Thymus • Three veins • Left brachiocephelic v. • Right brachiocephelic v. • Superior vena cava

43. Middle layer • Aotic arch and its three branches • Phrenic n. • Vagus n.

44. Posterior layer • Trachea • Esophagus • Thoracic duct

45. Relations of aortic arch • Anteriorly and to the left －pleura, lung，phrenic n., pericardiacophrenic vessels and vagus n. • Posteriorly and to the right－trachea, esophagus, left recurrent n., thoracic duct, deep cardiac plexus • Superiorly－its three branches, left brachiocephalic v. and thymus • Inferiorly－pulmonary a., arterial ligament, left recurrent n., left principal bronchus and superficial cardiac plexus

46. Triangule of ductus arteriosus 动脉导管三角 • Bounded by phrenic n., left vagus n. and left pulmonary a. • Contents－ arterial ligament , left recurrent n. and superficial cardiac plexuses

47. Inferior mediastinum下纵隔 Anterior mediastinum 前纵隔 • Location－posterior to body of sternum and attached costal cartilages, anterior to heart and pericardium • Contents－fat, remnants of thymus gland, anterior mediastinal lymph nodes

48. Middle mediastinum 中纵隔 • Location－between anterior mediastinum and posterior mediastinum • Contents: hart and pericardium, beginning or termination of great vessels, phrenic nerves, pericardiacophrenic vessels , lymph nodes,

49. Posterior mediastinum 后纵隔 • Location－posterior to heart and pericardium, anterior to vertebrae T5－T12 • Contents: esophagus, vagus n., thoracic aorta, azygos system of veins, thoracic duct, thoracic sympathetic trunk, posterior mediastinal lymph nodes

50. Relations of esophagus • Anteriorly－trachea, bifurcation of trachea, left principal branchus, left recurrent n., right pulmonary a., anterior esophageal plexus, pericardium, left atrium, diaphragm