Mediastinum/Pericardium Flashcards
What are the divisions of the mediastinum, and what separates them?
Superior
Inferior
- Anterior
- Middle
- Posterior
Superior and Inferior separated by Angle of Louis/Inferior border T4
What are the boundaries of the Superior Mediastinum? Contents?
Boundaries:
- Posterior to manubrium
- Anterior to Vertebral column
- Runs anterior to first 4 Thoracic Vertebrae
Contents:
- Aortic Arch (Including BrachioCephalic trunk and left subclavian/LCC
- BrachioCephalic veins
- Thymys
- Esophagus/trachea
- Thoracic Duct
- Vagus/Phrenic Nerves
What accompanies the Phrenic Nerve?
Pericardiophrenic artery
How do the Right/left phrenic nerves run?
Right: Right of SVC and RA
Left: Lateral to left vagus and AA
Both: Anterior to Root of lung between parietal pleura and fibrous pericardium
What are the borders and contents of the Anterior Inferior Mediastinum?
Boundaries: Extends from the posterior surface of the sternun to the anterior surface of the pericardial sac
Contents: Fat, Pericardium, Primary Bronchi, great vessels, and phrenic nerve
What are the borders and contents of the Posterior Inferior Mediastinum?
Boundaries: Located posterior to the pericardial sac and diaphragm, and anterior to the bodies of the inferior eight thoracic vertebrae (T5-T12)
Contents
- Esophagus
- Thoracic Aorta
- Thoracic Duct
- Azygos Veins
- Vagus and Splanchnic Nerves
What are the contents of the middle mediastinum?
- Heart and Pericardium
- Main Bronchi
- Great vessels
- Phrenic Nerve
Which pathologies cause contralateral tracheal deviations? Ipsilateral?
Contralateral:
- Tension Pneumothorax
- Pleural effusion
- Hemothorax
- Large Masses
Ipsilateral:
- Atelectasis
- Pneumonectomy
- Large Pleural fibrosis
Where is the Pericardium located?
Middle Media Stinum:
- Posterior to Sternum + CC 2-6
- Anterior to T5 - T8 Vertebrae
What are the ligamentous attachments for the pericardium?
Sternum —> Sternopericaardial ligament
Diaphragm —> Pericardiophrenic ligament
Which pericardium is reflected onto the heart where it forms the epicardium?
Visceral Pericardium
Describe the layers of penetration for the pericardium and heart.
Fibrous Pericardium Parietal layer serous sac Pericardial cavity Visceral Layer Serous sac (Epicardium) Endocardium Chamber of the heart
What are the two sinuses of the heart?
Transverse Sinus: Behind theAorta and Pulmonary trunk, and in front of LA and Sup Vena Cava.
Oblique Sinus: Between the pulmonary veins and inferior Vena Cava
What is the innervation and blood supply for the pericardium?
Innervation: Phrenic Nerve and Vagus Nerve
- Except Visceral layer —> Coronary plexus
Blood Supply:
- Internal thoracic —> Pericardiophrenic and musculophrenic arteries
- Thoracic Aorta —> Pericardial branches of Bronchial, esophageal, and sup phrenic arteries
- Except for visceral pericardium, —> Coronary arteries of ascending aorta
What are the clinical considerations for pericardium?
- Pericardial effusions
- Pericarditis (Friction rub)
- Pericardial Tamponade
Pericardiocentesis —> Large bore needle inserted at left sternal margin ICS 4 or paraxiphoid approach (substernal) to avoid intern thoracic artery
How is the heart divided in mediastinum?
Middle inferior Mediastinum
Obliquely and deviated so that 2/3 is left of median plane; 1/3 right of median plane
How are the base and apex of the heart positioned in the mediastinum? Which ribs does the heart relate to on the left? Which vertebrae does it extend through?
Base is posterior, apex is inferolateral
Medial ends of ribs 3-5
Posteriorly, Extends from T6-T9
What forms the base of the heart?
Where is the Apex located?
Base: Left Atrium
Apex: CC 6/ ICS 5
What is the blood supply and branches to the right heart?
Right Coronary
- Right Atrial Branch
- Conal Branch
- Right marginal —> Runs with Small cardiac vein
- Posterior Descending artery —> Runs with Middle cardiac vein
What is the blood supply And branches to the left heart?
Left Coronary:
- Circumflex (left marginal)
- Anterior descending; two diagonal branches —> Accompanies great cardiac vein
What structures are supplied by the right coronary artery?
- AV/SA Nodes
- Inferoposterior 1/3 septum
- Right Ventricle (Right marginal)
- PDA —> 1/3 RV and 2/3 LV
What structures are supplied by the left coronary artery?
- LAD —> LV, RV, and anterior 2/3 septum
- AV Bundle
- Circumflex —> LA/LV
- Marginal —> LV
What are the Astomoses of the heart?
- Nodal
- Conus arteriosus
- Circumflex
- ADA
- PDA
What venous structure lies within the coronary sinus?
Oblique vein
