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Thorax Sheet Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table.
✚ Educational reference. What this page summarizes is standard anatomy, set out for study. It is not medical advice, and it is no basis for diagnosis, for treatment, for surgical planning, or for any other clinical decision.
Muscles Muscles - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Muscle Origin Insertion Action Innervation Blood supply Accessory muscles of respiration Examples: sternocleidomastoid from sternum and clavicle; scalenes from cervical transverse processes; pectoralis minor from ribs 3–5 Corresponding attachments: mastoid and superior nuchal line; first or second rib; coracoid process. Fixing one end changes the respiratory mechanical effect Additional inspiratory force can elevate the rib cage; abdominal contraction raises abdominal pressure during active expiration. Recruitment varies with demand and posture. Sternocleidomastoid: accessory nerve with cervical contributions; scalenes: cervical anterior rami; pectoral muscles: pectoral nerves Separate regional supplies, including cervical branches for scalenes and thoracoacromial branches for pectoral muscles Diaphragm Inner xiphoid, lower six ribs and their cartilages, arcuate ligaments and lumbar crura; the right crus usually reaches L3 and the left L2 Central tendon, which is attached to the fibrous pericardium Lowers the domes to enlarge the thorax during inspiration; also helps raise abdominal pressure Right and left phrenic nerves, C3–C5 Inferior and superior phrenic arteries, with musculophrenic and pericardiacophrenic contributions External intercostals Lower edge of the rib above each space Upper edge of the next rib down Assists inspiration by elevating ribs and stabilizing the intercostal spaces Intercostal nerves from thoracic anterior rami, T1–T11 Anterior and posterior intercostal arterial branches
Bones Bones - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Bone Bone type Key landmarks Articulations Sternum Flat bone Manubrium; Sternal body; Xiphoid process; Manubriosternal angle; Jugular notch; Clavicular notches Clavicles at the sternoclavicular joints; costal cartilages of ribs 1–7 Typical rib Flat bone Head; Neck; Tubercle; Rib angle; Curved shaft; Costal groove Head with adjacent vertebral bodies in a typical rib; tubercle with the same-numbered vertebra's transverse process; anterior end with costal cartilage
Nerves Nerves - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Nerve Root value Course Motor Sensory Cardiac plexus Sympathetic preganglionic origin around T1–T5; parasympathetic input through cranial nerve X Interconnecting nerves near the aortic arch and tracheal bifurcation continue toward the heart; superficial and deep divisions are conventional descriptions Sympathetic stimulation generally accelerates rate and conduction and increases contractility; vagal stimulation slows sinoatrial and atrioventricular nodal activity Spinal afferents commonly accompany sympathetic pathways; vagal afferents participate in cardiovascular reflex signaling Greater splanchnic nerve Commonly T5–T9, with variable contributions Descends across the thoracic vertebral bodies and traverses the diaphragm toward the celiac ganglia Preganglionic sympathetic output; after a ganglionic relay, fibers reach foregut structures through abdominal plexuses Visceral afferents from upper abdominal organs, including foregut pain pathways Intercostal nerves Thoracic anterior rami T1–T11; T12 forms the subcostal nerve Cross the rib spaces mainly between internal and innermost intercostals, near the costal groove Intercostal muscles; lower thoracic branches also supply abdominal-wall muscles Segmental trunk skin and relevant parietal pleura; lower branches also carry abdominal-wall and parietal peritoneal sensation
Vessels Vessels - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Vessel Origin Course Branches Supplies Drains to Accessory hemiazygos vein Several left posterior intercostal veins in the upper-to-middle thorax Descends along the left side of the vertebral bodies and commonly crosses posterior to central mediastinal structures near T7–T8 Middle left posterior intercostal tributaries, with variable communicating veins Drains part of the left posterior thoracic wall Azygos or hemiazygos pathways; communication with the left superior intercostal vein may occur Anterior cardiac veins Veins of the anterior right ventricular myocardium Across the right AV junction toward atrial openings Variable small ventricular tributaries, sometimes communicating with marginal veins Drain the right ventricular wall; they do not provide arterial supply Direct right atrial openings, bypassing the coronary sinus Anterior interventricular artery (LAD) Usually a major division of the left main coronary stem Along the anterior interventricular groove toward the apex, with variable extension beyond it Septal perforators and diagonal ventricular branches Anterior left ventricular and septal myocardium, including much of the ventricular conducting system's arterial territory The supplied region returns blood through the great cardiac vein and other connected venous channels
Organs Organs - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Organ Location Parts Relations Blood supply Innervation Venous/Lymphatic drainage Function Alveolus In the gas-exchanging acinus, opening from respiratory bronchioles and alveolar ducts or sacs Alveolar epithelial cells, macrophages, connective-tissue septa and a dense capillary network not recorded Pulmonary capillaries closely associated with alveolar walls No skeletal motor supply; pulmonary visceral afferents sense mechanical and chemical changes in the distal lung Capillary blood returns through pulmonary venules; interstitial fluid reaches pulmonary lymphatic networks, including sparse deep intralobular channels Diffusion of oxygen and carbon dioxide across a short air-blood distance Aortic valve At the transition from left ventricular outflow tract to aortic root Usually right coronary, left coronary and non-coronary cusps, with adjoining sinuses and commissures Close to the anterior mitral leaflet and membranous septal conduction region; posterior to the pulmonary outlet Thin cusp tissue depends substantially on diffusion; small vessels can be present, especially near its attachments Autonomic and sensory fibers occur in valvar nerve networks, with uneven distribution not recorded Permits systolic ejection and limits aortic-to-ventricular backflow during diastole Atrioventricular bundle (of His) Between the AV node and ventricular bundle branches, through the central fibrous body toward the septal crest A penetrating segment followed by the axis that gives rise to the ventricular branches Near the membranous septum, aortic root and septal tricuspid attachment Usually contributions from the AV nodal artery and anterior interventricular septal branches; their extent varies Cardiac autonomic influences modulate these conducting cardiomyocytes not recorded Transfers atrial excitation from the AV node into the ventricular conducting branches
Joints Joints - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Joint Joint type Articulating surfaces Ligaments Movements Blood supply Costovertebral joints Synovial joints at the rib head and costotransverse articulation Typical head with the same-numbered vertebra, vertebra above and intervening disc; tubercle with the same-numbered transverse process Radiate and intra-articular ligaments at the head; costotransverse, lateral costotransverse and superior costotransverse ligaments Small rotation and gliding allow combined pump- and bucket-handle rib movement; ribs 11–12 lack costotransverse joints Articular branches of posterior intercostal arteries
Ligaments Ligaments - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Ligament Attachments Function Clinical point Central tendon of the diaphragm Receives the surrounding diaphragm fibers; attached superiorly to fibrous pericardium, with no direct insertion into bone Collects and transmits muscular force as the diaphragm descends; contains the caval passage The pericardial attachment links this tendon anatomically to the sac around the heart Chordae tendineae Papillary muscles or ventricular wall to the margins and ventricular surfaces of mitral or tricuspid leaflets Restrain leaflet prolapse and distribute force through the valve–ventricle apparatus during systole Disrupted chordal support can produce a flail leaflet segment and valvar regurgitation Fibrous skeleton of the heart Connective tissues at valve attachments, including right and left fibrous trigones, aortic–mitral continuity and the membranous septal region Supports valves and myocardium and electrically separates ordinary atrial and ventricular muscle The nearby penetrating atrioventricular bundle can be affected by disease or procedures around the central fibrous body
Spaces Spaces - Thorax Sheet. Every thoracic structure on one sheet - chest wall, mediastinum, heart, lungs and great vessels, each type in its own table. Space Boundaries Contents Communications Aortic hiatus Median arcuate ligament in front, diaphragmatic crura at the sides and vertebral column behind, conventionally near T12 Aorta and thoracic duct; an azygos-system vein may also pass through this region Posterior mediastinum to the upper retroperitoneal region Aortic sinuses (of Valsalva) The root wall and corresponding cusp enclose each sinus, extending upward to the sinotubular junction Blood-filled spaces, usually with right and left coronary ostia in their named sinuses Continuous with the aortic lumen; the coronary ostia lead into the coronary arteries Cardiac auscultation areas Common anterior chest landmarks extend from the second parasternal interspaces to the lower sternal border and cardiac apex These are listening sites over chest-wall tissues, not a distinct anatomical cavity Cardiac vibrations travel through blood and surrounding tissues; their audible distribution depends on the sound and anatomy
Built from the thorax records of the AnatoMemory reference library.
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