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ThoracicAnatomy Donovan Campbell 4th Year Medical Student Queen's University BelfastLearningOutcomes o Mediastinum o Thoracic Wall o Tracheobronchial Tree o Lungs and Pleurae o Main Neurovasculature o Lymphatics o Breast SuperiorMediastinum Borders Superior – Thoracic inlet (aperture). Inferior – The transverse plane of Ludwig. Anterior – Manubrium. Posterior – Vertebral bodies of T1-4. Lateral – Pleurae of the lungs. ThiemeAtlas of Anatomy1) Whatistheborderthatseparatesthe superiorandinferiormediastinum? •Angle of Louie •Caval Hiatus •Thoracic Aperture •Transverse Plane of Ludwig •Aortic Arch1) Whatistheborderthatseparatesthe superiorandinferiormediastinum? •Angle of Louie •Caval Hiatus •Thoracic Aperture •Transverse Plane of Ludwig •Aortic Arch SuperiorMediastinum Phrenic N. Vagus N. Contents – Thoracic Duct Private Left Left recurrent laryngeal N. Battle Brachiocephalic Vein Aortic Arch Thymus Trachea Lymph node OesophagusAnteriorMediastinum Borders Lateral borders - Mediastinal pleurae. Anterior border - Sternal body and transversus thoracis muscles. Posterior border - Pericardium. Roof - The transverse plane of Ludwig. Floor - Diaphragm.AnteriorMediastinum Clinical Relevance – All the T's Contents • Teratoma • Thymus • Thymic • Sterno-pericardial carcinomas/thymomas ligaments • Thyroid Carcinomas • Lower pole of thyroid gland • Terrible Lymphomas • Internal thoracic vessels • Para-sternal lymph nodes2)Whichofthefollowingstructuresislocated inthesuperiormediastinum? •Sterno-pericardial ligaments •Lower pole of the thyroid gland •Omohyoid •Thoracic Duct •Descending Aorta2)Whichofthefollowingstructuresislocated inthesuperiormediastinum? •Sterno-pericardial ligaments •Lower pole of the thyroid gland •Omohyoid •Thoracic Duct •Descending AortaPosteriorMediastinum Borders Lateral - Mediastinal pleura. Anterior - Pericardium. Posterior - T5-T12 vertebrae. Roof - The transverse plane of Ludwig. Floor - Diaphragm. PosteriorMediastinum Contents – DATES in Vegas Descending Aorta Azygous/hemiazygous veins Thoracic Duct Oesophagus Sympathetic Chain Vagus Nerve – Anterior + Posterior Trunks3)Whatistheanteriorborderoftheposterior mediastinum? •Pericardium •Manubrium •Diaphragm •T5-T12 •Tranversus Thoracis3)Whatistheanteriorborderoftheposterior mediastinum? •Pericardium •Manubrium •Diaphragm •T5-T12 •Tranversus ThoracisThoracicWall Key Landmarks: T4 –nipple ThiemeAtlas of Anatomy T6 –xiphoid processThoracicWall Typical Ribs • Ribs 3-9. • Contains of a head, neck, tubercleand body. Atypical Ribs • 1,2,10-12. •Rib 1 – Only one facet for articulation with its corresponding vertebra. •Rib 2 - Tuberosity from which serratus anterior originates. •Rib 10 - Only onefacet. •Ribs 11 - 12 No neck and only contain one facet. ThoracicMusculature Muscle Origin Insertion Innervatio Action n Externalintercostal Lower marginofrib Upper marginofnext lower 1st-11th Elevates ribs on rib (obliquely forward and intercostal inspiration. downward from costal tubercle to chondro-osseous junction) Internalintercostal Lower marginofrib Upper marginofnext 1st-11th Depresses ribs on lower rib (obliquely forward intercostal expiration and upward from costalangle tosternum) Innermost intercostal Lower marginofrib Same as above 1st-11th Depresses intercostal ribs onexpirationThoracicWall4)Whatactiondoestheexternalintercostal musclehaveduringinspiration? •Depresses Ribs •Elevates Ribs •Protracts Ribs •Stabilises Ribs •Rotates Ribs4)Whatactiondoestheexternalintercostal musclehaveduringinspiration? •Depresses Ribs •Elevates Ribs •Protracts Ribs •Stabilises Ribs •Rotates Ribs ThoracicMusculature Muscle Origin Insertion Innervation Action Pectoralis Major Medial ½ of clavicle, ant. Lateral lip of Medial + lateral pectoral Adduction, humeral surfaceof sternum, 1st 7 intertubercular sulcus nerves flexion and medial costal cartilages + of humerus rotation external oblique aponeurosis Pectoralis Minor Ant. surfaceof ribs 3-5 Coracoid process Medial pectoral nerve Pulls claviclemedially and deep fascia stabilising SC joint. associated with Depresses shoulder tip associated intercostal space Subclavius 1st rib between cartilage Grooveon inferior middle Nerveto subclavius Depresses shoulder tip. and rib 1/3 of clavicle Protracts scapula Serratus Anterior Lateral aspects of ribs 1- Costal surfaceof the Long thoracic nerve Rotates scapula + 8 medial border of the protracts scapula scapula.ThoracicMusculature ThoracicMusculature Muscle Origin Insertion Innervation Action Anterior Scalene C3-6 –transverse 1st rib (ant. Scalene Anterior ramiofC4-6 Ribs mobile processes (anterior) tubercle) (inspiration) – elevates upper ribs. Middle Scalene C1-2 tranverse 1st rib posterior to Anterior ramiofC3-8 Ribs processes subclaviangroove mobile (inspiration) C3-7 tranverse –elevates upper ribs. processes (posterior) Posterior Scalene C5-7 transverse 2nd rib Anterior C6-8 Ribs processes (posterior) mobile (inspiration) –elevates upper ribs. Subcostal Lower marginof Ribs 2-3 below Adjacent intercostal Depresses ribs on lower ribs expiration Tranversus Thoracis Sternum (inner 2nd-6thribs (costal 2nd-6thintercostal Weakly depresses surface) cartilage) ribs onexpirationThoracicVertebrae Typically... Two demifacets • Superior articulates with head of corresponding rib. • Inferior with the head of rib below. Tranverse costal facet • Formed at the end of tranverse process > tubercle of own rib. ThiemeAtlas of AnatomyTracheobronchialTree Ciliated Pseudostratified Columnar Epithelium5)AchildisbroughttoinA&E.Theyhavechokedona marbleandsincehavebeendistressedanddyspnoeic. Whereisthemarblemostlikelylocated? •Left Main Bronchus •Right Main Bronchus •Oesophagus •Right Upper Lobe Bronchus •Left Upper Lobe Bronchus5)AchildisbroughttoinA&E.Theyhavechokedona marbleandsincehavebeendistressedanddyspnoeic. Whereisthemarblemostlikelylocated? •Left Main Bronchus •Right Main Bronchus •Oesophagus •Right Upper Lobe Bronchus •Left Upper Lobe BronchusTracheobronchialTree Conducting Portion: Segmental(tertiary) bronchus – terminalbronchiole. Respiratory Portion: Respiratory bronchiole –alveoli. ThiemeAtlas of AnatomyTheLungs ThiemeAtlas of AnatomyTheLungsTheLungs https://www.instantanatomy.net/thorax/areas/respiratorysystem/impressions.htmlTheLungs https://www.instantanatomy.net/thorax/areas/respiratorysystem/impressions.html ThePleurae Pleuralcavity A potential space. It contains 10-20mlofserous fluid. • It lubricates the surfaces ofthe pleurae. • Produces a surface tension, pulling the parietal and visceral pleura together. This ensures that when the thorax expands,the lung alsoexpands,filling withair. Serous membranes facilitating efficient respiration. Layer of simple squamousepithelium (mesothelium)https://radiopaedia.org/cases/tra umatic-pneumothorax-3ArterialSystem The posterior intercostal arteries anastomose with the anterior intercostal arteries to supply the structures of the thoracic wall. The posterior intercostal arteries branch from the thoracic aorta, except for the 1st and 2nd, which arise from the superior intercostal artery (a branch of the costocervical trunk). ThiemeAtlas of Anatomy6) What is the origin of the Costocervical Trunk? •Axillary Artery •Internal Thoracic Artery •Subclavian Artery •Musculophrenic Artery •Anterior Intercostal Artery 6) What is the origin of the Costocervical Trunk? •Axillary Artery Subclavian – VITCD•Internal Thoracic Artery V – Vertebral I – Internal Thoracic •Subclavian Artery C – Costocervical Trunksculophrenic Artery D – Dorsal Scapular •Anterior Intercostal ArteryArterialSystemPulmonaryVasculatureSystem ThiemeAtlas of AnatomyVenousSystem ThiemeAtlas of AnatomyVenousSystem ThiemeAtlas of AnatomyAzygousSystem ThiemeAtlas of Anatomy7) At which vertebral level does the azygous drain into the SVC? •C7 •T4 •T6 •T8 •T107) At which vertebral level does the azygous drain into the SVC? •C7 •T4 •T6 •T8 •T10 NervousSystem Parasympathetic – from the vagus nerve. They stimulate secretion from the bronchial glands, contraction of the bronchial smooth muscle and vasodilation of the pulmonary vessels. Sympathetic – derived from the sympathetic trunks. They stimulate relaxation of the bronchial smooth muscle, and vasoconstriction of the pulmonary vessels.LymphaticsLymphatics Lungs are drained by 2 networks. Peribronchial > drains bronchialand most ofthe lungs. Subpleural > peripherallungs and visceralpleura. ClinicalRelevance Chylothorax –leakage ofchyle intothe thorax. Causes - Iatrogenic, malignancy,trauma, congenital, infection... Oesophagus 4 Points of Constructions Fibromuscular tube 25 cm in length, mucosal • Cricoid Cartlidge layer consisting of non- • Aortic Arch • Left Main Bronchus keratinising stratified • Diaphragmatic Hiatus squamous epithelium. Origin – cricoid cartilage (c6) Insertion – cardiac orifice (T11)Oesophagus Arterial Supply • Oesophageal branches of inferior thyroid artery (thyrocervical). • Oesophageal branches of aorta. • Right intercostal arteries. Metaplasia > columnar epithelium. (Adenocarcinoma) Venous • Branches of the azygous veins. Squamous cellcarcinoma –most prevalent • Inferior thyroid vein. Nerve • Oesophageal plexus. • Parasympathetic vagal trunks • Sympathetic fibres from the cervical and thoracic sympathetic trunks.8) What vertebral level does the Oesophagus pass through the diaphragm? •A – T8 •B – T9 •C – T10 •D – T11 •E – T12 8) What vertebral level does the Oesophagus pass through the diaphragm? •A – T8 REMINDER •B – T9 •C – T10 "Oesophagus" •D – T11 10 letters •E – T12T8 Inferior VenaCava CavalHiatus Right Phrenic N T10 Oesophagus OesophagealHiatus R+L Vagus NN Oesophagealbranches of LGA/V T12 Aorta Aortic Hiatus Thoracic Duct Azygous Vein C3,4,5 Keep the diaphragm...BreastAnatomy Dimensions • From lateralsternum tomid axillary line. • From 2nd to6thcostalcartilages. Mammary Glands They consist of15-20 ducts and secretory lobules. Eachlobule consists ofmany alveolidrained by a single lactiferous duct. Connective Tissue Stroma Supportive structure surrounding mammary glands. It has a fibrous and a fatty component. Fibrous>suspensory lig. (Coopers) Pectoral Fascia Attachment point for the suspensory ligaments. ThiemeAtlas of Anatomyse CT knownas retromammary space.9)Whatarterydoestheinternalthoracic arterycomeoff? •Axillary Artery •Subclavian Artery •Ascending Aorta •Aortic Root •Brachiocephalic Artery9)Whatarterydoestheinternalthoracic arterycomeoff? •Axillary Artery •Subclavian Artery •Ascending Aorta •Aortic Root •Brachiocephalic ArteryBreastVasculature ArterialSupply Medial - InternalThoracic Artery Lateral - LateralThoracic - Thoracoacromial - LateralMammary - Mammary BranchofAnterior Intercostal Venous Medial - InternalThoracic Vein Lateral Same as arterial ThiemeAtlas of AnatomyBreastNervousSupply Anterior and lateral cutaneousbranchesof the 4thto6thintercostalnerves. Input from theSupraclavicular nerves. These nerves containbothsensory and autonomic nerve fibres. • Autonomic fibres regulate smoothmuscle and blood vesseltone. ThiemeAtlas of AnatomyBreastLymphatics Drainage in 3 groups: • Axillary nodes (75%) • Parasternalnodes (20%) • Posterior intercostalnodes (5%) Skin Drains to theaxillary, inferior deep cervical and infraclavicular nodes. Nipple and areola Drains to thesubareolar lymphatic plexus.10)Whatisanalternativenametothesuperior mediastinallymphnodeknownas4RAND4L? •Upper paratracheal •Lower paratracheal •Retrotracheal •Pre vascular tracheal •Subaortic10)Whatisanalternativenametothesuperior mediastinallymphnodesknownas4Rand4L? •Upper paratracheal •Lower paratracheal •Retrotracheal •Pre vascular tracheal •SubaorticResources • Gray's Anatomy for Students • Thieme Atlas of Anatomy • Radiopaedia • TeachMe Anatomy • Kenhub Thank you all! Email: gcampbell47@qub.ac.uk Questions??