1. ThoraxMUHAMMAD RAMZAN UL REHMAN1

2. The muscles of thoraxExtrinsic muscles Pectoralis major Pectoralis minor Serratus anteriorIntrinsic muscles Intercostales externi Intercostales interni Intercostales intimi Transverses thoracis2 3. Intercostales externi Origin: lower border of ri) Insertion: upper border of ribbelow origin Action: elevate ribs addingin forced inspiration Replaced anteriorly byexternal intercostalsmembrane.Intercostales interni Origin: upper border of rib Insertion: lower border of ribabove origin Action: depress ribs forforced expiration Replaced posteriorly byinternal intercostalsmembrane.3 4. DiaphragmShape and position:dome-shaped between thorax andabdomen, consists of a peripheralmuscular part and a centraltendonOrigin Sternal part: xiphoid process Costal part: lower six and costalcartilages Lumbar part: arises by two crurafrom upper 2-3 lumbar vertebrae Insertion: central tendonWeak areas: triangular spaceswithout muscular tissue Lumbocostal triangle: betweencostal and lumbar parts. Sternocostal triangle: betweencostal and sternal parts.4 5. Openings in the diaphragm Aortic hiatuslies anterior to the body of the 12ththoracic vertebra between the crura. It transmits theaorta, thoracic duct Esophageal hiatus for esophagus and vagus nervesat level of T10. Vena cava foramen for inferior vena cava, throughcentral tendon at T8 level5T8T10T12 6. Action: Contraction: the domemoving downward,increases the volume ofthoracic cavity whichresults in inspiration, atthe same time the intra-abdominalpressure isincreased assists indefecation, vomiting orchild birth. Relaxation: the domereturns to the formerposition, reduces thevolume to the thoraciccavity, resulting inexpiration.6 7. Arteries of thoraxPulmonary trunk Arises from right ventricle Runs up, back ,and to the left Bifurcates inferior to aortic archinto right and left pulmonaryarteries, one for each lungPulmonary arteries Right pulmonary arterypassesposterior to ascending aortaand superior vena cava tohilum of right lung Left pulmonary arterypassesanterior to descending aortaand left main bronchus to hilumof left lung7 8. Arterial ligament remnant of ductus arteriosus, connectsbifurcation of pulmonary trunk to inferior border of aorticarchTriangule of ductus arteriosus Bounded by phrenic n., left vagus n. and left pulmonary a. Contents arterial ligament , left recurrent n. and superficialcardiac plexuses8 9. Ascending aorta Runs upward, forwardand to the right, Extends to level ofsecond rightsternocostal joint Branches: right andleft coronary arteries9 10. Aortic arch Continuation of ascending aorta Curves upward, to the left andposteriorly, then downward,arching over left principalbronchus and pulmonary trunk tolower border of T4 level, tobecome descending aorta Branches (from right to left ) Brachiocephalic trunkextendsto right sternoclavicular joint,bifurcates into right subclavianand right common carotidarteries Left common carotid artery Left subclavian artery Aortic isthmusbaroreceptor Aortic glomerachemoreceptor10 11. Thoracic aorta Continuation of aortic arch at lower border of T4 Courses downward on left side of, then in front ofvertebral column Passes through aortic hiatus of diaphragm atlevel 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 andupper part of abdominal wall; superiorphrenic arteries supply the superiorsurface of the diaphragm. Visceral branches Bronchial branches: one or two for eachlung Esophageal branches Pericardial branches11 12. Internal thoracic artery descends into thorax1.2cm lateral to edgeof sternum, and endsat the sixth costalcartilage by dividingmusculophrenic andsuperior epigastricarteries12 13. 13 14. Veins of thoraxBrachiocephalic veins Formed by union of internal jugular andsubclavian veins posterior to thesternoclavicular joint Angle of union is termed venous angleSuperior vena cava Formed by union of right and leftbrachiocephalic veins behind the rightsternocostal synchorndrosis of first rib Runs vertically down on right ofascending aorta Joined by azygos vein at level of sternalangle Enters right atrium at lever of lowerborder of third right sternocostal joint Collects blood from veins of upper halfof body14 15. Azygos vein Begins as continuation of rightascending lumbar vein Ascending along the right side ofvertebral column Joins superior vena cava byaching above right lung root atlevel of T4 to T5 Receives right posterior intercostalsand subcostal veins plus some ofbronchial, esophageal andpericardial veins, and hemiazygosvein Tributarieshemiazygosv. andaccessory hemiazygos v. whichreceive most left posteriorintercostals vein and left bronchialveins15 16. Veins of vertebral columnConsists of External vertebralvenous plexus Internal vertebralvenous plexus16 17. The lymphatic drainage of thoraxThe lymphatic drainage of thoracicwall To axillary lymph nodes To parasternal lymphnodes (along internalthoracic vessels) To intercostals lymphnodes from deeperstructures17 18. lymph nodes of the thoracic contentslymph nodes of trachea,bronchi and lungs Pulmonary lymph nodes lie inthe angles of bifurcation ofbranching lobar bronchi Bronchopulmonary hilar lymphnodeslie in the hilus of thelung Tracheobronchial lymph nodessituated above or below thebifurcation of trachea Paratracheal lymph nodesalong each side of thetrachea18 19. Anterior mediastinallymph node lies anteriorto the large blood vessels ofthoracic cavity andpericardium; the efferentsunite with those ofparatracheal lymph nodes,to form the right and leftbronchomediastinal trunks .The left bronchomediastinaltrunk terminates in thoracicduct, and right in the rightlymphtic duct Posterior mediastinallymph nodes lie alongthe esophagus and thoracicaorta19 20. Thoracic duct Begins in front of L1 as a dilated sac,the cisterna chyli, which formed byjoining of left and right lumbar trunksand intestinal trunk Enter thoracic cavity by passingthrough the aortic hiatus of thediaphragm and ascends along on thefront of the vertebral column,between thoracic aorta and azygosvein Travels upward, veering to the left atthe level of T5 At the roof of the neck, it turns laterallyand arches forwards and descends toenter the left venous angle20 21. Just before termination, it receivesthe left jugular, subclavian andbronchomediastinal trunks Drains lymph from lower limbs,pelvic cavity, abdominal cavity,left side of thorax, and left side ofthe head, neck and left upper limbRight lymphatic duct Formed by union of right jugular,subclavian, andbronchomediastinal trunks Ends by entering the right venousangle Receives lymph from right half ofhead, neck, thorax and right upperlimb21 22. Anterior branches of thoracic nerves Intercostal nerves (anterior rami ofT1- T11): runs forward inferiorly tointercostals vessels in costal grooveof corresponding rib, betweenintercostals externi and intercostalsinterni; first six nerves are distributedwithin their intercostals space,lower five intercostals nerves leaveanterior ends of their intercostalsspaces to enter abdominal wall Subcostal nerve (anterior ramus ofT12): follows inferior border of T12rib and passes into abdominal wall Distribution: distributed tointercostales and anterolateralabdominal muscles, skin ofthoracic and abdominal wall,parietal pleura and peritoneum22 23. The segmental innervation of anterior surface oftrunk T2sternal angle T4 nipple T6xiphoid process T8costal arch T10umbilicus T12midpoint between umbilicusand symphysis pubis23 24. 24 25. Phrenic nerve Descends over scalenusanterior to enter thorax Accompanied bypericardiophrenic vesselsand passes anterior to lungroots between mediastinalpleura and pericardium tosupply motor and sensoryinnervation to diaphragm Sensory fibers supply topleurae, pericardium andperitoneum of diaphragm;usually right phrenic nervemay be distributed on live,gallbladder and biliarysystem.25 26. Left vagus nerve Enter thoracic inlet between leftcommon carotid and leftsubclavian arteries, posterior toleft brachiocephalic vein Crosses aortic arch where leftrecurrent laryngeal nervebranches off Passes posterior to left lung root Forms anterior esophageal plexus Forms anterior vagal trunk atesophageal hiatus where itleaves thorax and passes intoabdominal cavity , then dividesinto anterior gastric and hepaticbranches26 27. Right vagus nerve Enter thoracic inlet on rightside of trachea Travels downward posteriorto right brachiocephalic veinand superior vena cava Passes posterior to right lungroot Forms posterior esophagealplexus Forms posterior vagal trunk atesophageal hiatus where itleaves thorax and passes intoabdominal cavity, thendivides into posterior gastricand celiac branches27 28. 28Recurrent laryngeal nerves Right one hooks around rightsubclavian artery, left one hooksaortic arch Both ascend in tracheo-esophagealgroove Nerves enter larynx posterior tocricothyroid joint, the nerve isnow called inferior laryngealnerve Innervations: laryngeal mucosabelow fissure of glottis , alllaryngeal laryngeal musclesexcept cricothyroidBronchial and esophagealbranches 29. 29 Thoracic sympathetic trunk Branches of sympathetic trunk tothoracic plexuses Greater splanchnic nerve formed bypreganglionic fibers from T5~T9ganglia, and relay in celiac ganglion. Lesser splanchnic nerve formed bypreganglionic fibers from T10~T12ganglia, and relay in aorticorenalganglion. The postganglionic fibers supply theliver, spleen, kidney and alimentarytract as far as the left colic flexure. 30. Regional anatomy ofthorax30 31. Parts and regions of the thoraxBoundaries Superiorjugular notch,sternoclavicular joint, superiorborder of clavicle, acromion,spinous processes of C7 Inferiorxiphoid process, costalarch, 12th and 11th ribs, vertebraT12Regions Thoracic wall Thoracic cavity31 32. Landmarks Jugular notch corresponds with The 2th thoracic vertebra inmale, the 3th thoracicvertebra in female Sternal angle connects 2ndcostal cartilage laterallycorresponds with The lower border of 4ththoracic vertebra The bifurcation of trachea inthe adult The beginning of aortic archwhich ends posteriorly at thesame level The esophagus is crossed bythe left main bronchus32 33. Xiphoid processphisternaljunction liesopposite the body of the9th thoracic vertebra Clavicle Inferior fossa of clavicle Coracoid process Ribs and intercostalspaces Costal arch Infrasternal angle Xiphocostal angle Papillae33 34. Thoracic wall Skin Superficial fascia Thoracoepigastric v. Supraclavicular n. Anterior and lateral cutaneousbranches of intercostal n. Deep fascia34 35. Intercostal space35Posterior intercostal v.Posterior intercostal a.Intercostal n. 36. Lymphatic drainage of breast Into pectoral ln. from lateraland central parts of breast Into apical and supraclavicularln. from superior part of breast Into parasternal ln. from medialpart of breast Into interpectoral ln. from deeppart of breast The lymphatic capillaries ofbreast form an anastomosingnetwork which is continuousacross the midline with that ofthe opposite side and with thatof the abdominal wall36 37. Internal thoracic vessels Internal thoracic a.&v. Parasternal ln.Endothoracic fascia37 38. The MediastinumConceptall oforgans between theleft and rightmediastinal pleurae iscalled mediastinum.It extends from thesternum in front to thevertebral columnbehind, and from thethoracic inlet aboveto the diaphragmbelow.38 39. Subdivisions of mediastinum Superior mediastinum Inferior mediastinum Anterior mediastinum Middle mediastinum Posterior mediastinum39 40. Left side of mediastnum 40Left vagus n.Left subclavian a.Thoracic ductAortic archLeft recurrent n. Thoracic aortaPhrenic n. &pericardiacophrenic a.Root of lungPericardiumSympathetic trunkGreater splanchnic nEsophagus 41. Right side of mediastnum 41Superior vena cavaPhrenic n. &pericardiacophrenic a.Root of lungPericardiumTracheaLeft vagus n.Arch of azygos v.Azygos v.Sympathetic trunkEsophagusInferior vena cava 42. Superior mediastinumLocatingfrom inlet of thoraxto plane extending fromlevel of sternal angleanteriorly to lower border ofT4 vertebra posteriolyContents Superficial layer Thymus Three veins Left brachiocephelic v. Right brachiocephelic v. Superior vena cava42 43. Middle layer Aotic arch and itsthree branches Phrenic n. Vagus n.43 44. Posterior layer Trachea Esophagus Thoracic duct44 45. Relations of aortic arch Anteriorly and to the left pleura, lungphrenic n.,pericardiacophrenic vesselsand vagus n. Posteriorly and to the righttrachea,esophagus, leftrecurrent n., thoracic duct,deep cardiac plexus Superiorlyits three branches,left brachiocephalic v. andthymus Inferiorlypulmonary a.,arterial ligament, left recurrentn., left principal bronchus andsuperficial cardiac plexus45 46. Triangule of ductus arteriosus Bounded by phrenic n., left vagusn. and left pulmonary a. Contents arterial ligament , leftrecurrent n. and superficialcardiac plexuses46 47. Inferior mediastinumAnterior mediastinum Locationposterior to bodyof sternum and attachedcostal cartilages, anterior toheart and pericardium Contentsfat, remnants ofthymus gland, anteriormediastinal lymph nodes47 48. Middle mediastinum Locationbetweenanterior mediastinumand posteriormediastinum Contents: hart andpericardium, beginningor termination of greatvessels, phrenic nerves,pericardiacophrenicvessels , lymph nodes,48 49. Posterior mediastinum Locationposterior to heartand pericardium, anterior tovertebrae T5T12 Contents: esophagus, vagusn., thoracic aorta, azygossystem of veins, thoracicduct, thoracic sympathetictrunk, posterior mediastinallymph nodes49 50. Relations of esophagus Anteriorlytrachea,bifurcation of trachea, leftprincipal branchus, leftrecurrent n., rightpulmonary a., anterioresophageal plexus,pericardium, left atrium,diaphragm50 51. Posteriorlyposterioresophageal plexus, thoracicaorta, thoracic duct, azygosv., hemiazygos v.,accessoryhemiazygos v., right posteriorintercostal v.51 52. Leftleft common carotid a., left subclavian a., aorticarch, thoracic aorta, superior part of thoracic duct Rightarch of azygos v.52 53. Relations of thoracic aorta Anteriorlyleft root of lung,pericardium and esophagus Posterior hemiazygos v.,accessory hemiazygos v., Rightazygos v. and thoracicduct Leftmediastinal pleura53 54. Mediastinal spaces Retrosternal space liesbeween sternum andendothoracic fascia Pretracheal space lies withinsuperior mediastinum,between trachea, bifurcationof trachea and aortic arch Retroesophagus space lies within superiormediastinum, beweenesophagus and endothoracicfascia54