Heart and Mediastinum Flashcards
Location of Heart
- inferior part of anterior mediastinum
- Projection: 30-33-59-62
- rotated 60 degrees left in sagittal axis, 30 degrees up in transverse axis, 15 degrees left around heart axis
- heart axis: line between middle of spine of scapula and apex of heart
Surfaces of Heart
- Sternocostal (RA, RV, LV)
- Diaphragmatic (RV, LV, RA)
- Posterior (LA)
- Right Pulmonary (RA)
- Left Pulmonary (LV)
Parietal Pericardium
- continues with tunica adventitia of great vessels + leaves heart via pre tracheal layer of cervical fascia
- composed of outer fibrous layer + inner serous layer
- Connections:
- sternopericardial ligament
- pleuropericardial membrane
- percardiophrenic ligament ⇒ central tendon of diaphragm
Visceral layer of pericardium
- reflected onto heart and great vessels as visceral layer of serous pericardium
- arterious reflection
- venous reflection
- all reflections together ⇒ Sappey’s T
Pericardiac sinuses
- Transverse sinus: between main arteries and main veins
2. Oblique sinus: at venous reflection behind heart, blind recess
Blood supply of Pericardium
ARTERY:
- Pericardiophrenic artery (internal throacic artery)
- Musculophrenic artery (internal thoracic artery)
- Superior Phrenic arteries (thoracic aorta)
- Coronary arteries
VEIN:
- Pericardiophrenic vein ⇒ Brachiocephalic vein
- Azygos venous system
Innervation of Pericardium
Phrenic nerve (sensory) Sympathetic trunk (vasomotor)
Layers of Heart
- Outer fibrous layer of parietal pericardium
- Inner serous layer of parietal pericardium
- Visceral pericardium (epicardium)
- Myocardium
- outer oblique/longitudinal
- middle circular
- inner longitudinal - Endocardium
Pericardial cavity
potential space between parietal and visceral layers of pericardium.
contains serous fluid⇒ lubrication + allows free movement
Crux Cordis (Cross of Heart)
posteriorly where inter ventricular sulci join the coronary sulcus
Waterson’s groove
between the right pulmonary veins and right atrium
Ligamentum arteriosum
short band which is remnant of fetal ductus Arteriosus, can be found between aortic arch and pulmonary trunk
Koch triangle
content: AV node borders: * sup: tendon of Todaro * inf: tricuspid valve annulus * post: Thebasian valve of coronary sinus
Fila coronaria
threadlike structure arising from fibrous trigone and encircling nearby valves
Conus Arteriosus tendon
a stripe of fibrous tissue structure that is situated between the aortic root and pulmonary trunk.
extends upward from the right AV fibrous ring and connects the posterior surface of the conus arteriosus to the aorta
Cusped valves
- Mitral: anterior and posterior cusps
- Tricuspid: anterior, posterior and septal cusps
- cusps divided into: rough zone and clear zone
- cusps are attached to chord tendinae ⇒ papillary muscle ⇒ prevent flipping back to atria
Semilunar valves
- aortic: posterior, right and left cusps
- pulmonary: anterior, right and left cusps
- commissure between cusps
- 2 parts: pars densa + pars flaccida- 2lunules + 1 nodule
- superiorly to cusps⇒ aortic/pulmonary sinus
Auscultation of Heart valves
- Aortic valve: 2 IC, 2 cm right
- Pulmonary valve: 2 IC, 2 cm left
- Tricuspid valve: 5 IC, 2 cm left
- Mitral valve: 5 IC, 9 cm left
- Erb’s point: 3 IC, 3cm left
Right Coronary artery
right anterior aortic sinus ⇒ coronary groove BRANCHES: - conus arteriosus - ascending sinoatrial - right marginal - right ventricular - atrioventricular nodal - posterior interventricular
Left Coronary artery
left anterior aortic sinus ⇒ coronary groove BRANCHES: - anterior interventricular branch: * anterior septal * left and right ventricular * lateral diagonal * ascending sinoatrial - circumflex: * left marginal * left atrial * left posterior lateral
Coronary artery dominance
- the artery that supplies the posterior descending artery and the AV- node determine the coronary dominance
- 70% right-dominant
- 20% co-dominant
- 10% left-dominant
Venous drainage of Heart
- Great cardiac vein: anterior IV groove ⇒ coronary sulcus ⇒ coronary sinus
- Middle cardiac vein: posterior IV groove ⇒ coronary sinus
- Small cardiac vein: runs with marginal branch of RCA ⇒ coronary sinus
- Posterior vein of left ventricle: posterior surface ⇒ coronary sinus
- Anterior small cardiac branches: anterior surface of RV⇒ directly to RA
- Least Cardiac veins: anterior surface of LV⇒ directly to LA
Conducting system
SA node ⇒ internodal patway ⇒ AV node ⇒ Bundle of His ⇒ Tawara branches ⇒ Purkinje fibers
Innervation of Heart
sympathetic: fibers from cervical ganglia and stellate ganglion and thoracic ganglion
parasympathetic: vagus nerve
Supracardiac mediastinum layers
- Sternum
- Thymus
- Brachiocephalic vein + SVC
- Vagus + Phrenic nerve
- Ascending aorta + aortic arch with branches
- Trachea
- Recurrent laryngeal nerve
- Esophagus
- Vertebral column
Posterior mediastinum layers
- Thoracic aorta
- Esophagus + Vagus nerves
- Thoracic duct + lymph trunks
- Axygos vein + hemiazygos vein + accessory hemiazygos vein
- 2 sympathetic trunks + Lower Splanchnic nerves