Mediastinum Overview and Pericardium Flashcards
What nerve innervates the pericardium?
Phrenic nerve
The phrenic nerve is involved due to its developmental connection with the pleuropericardial membrane.
What membrane includes the phrenic nerve during development?
Pleuropericardial membrane
This membrane separates from the developing body wall as the pleural cavities form.
What are the primordial pleural cavities?
Canals that run on both sides of the foregut
These cavities connect the thoracic and abdominal cavities.
What happens to the body wall mesenchyme during lung development?
It splits into two layers: outer and inner
The outer layer becomes the thoracic wall, while the inner layer forms the pleuropericardial membranes.
What is the significance of the transverse thoracic plane?
It defines the division between superior and inferior mediastinum
This division is mostly independent of gravitational effects.
How does gravity affect the position of mediastinal structures when a person is supine?
Viscera are positioned higher relative to mediastinal subdivisions
In the supine position, the abdominal viscera spread horizontally.
When a person is upright, where is the arch of the aorta in relation to the transverse thoracic plane?
It is transected by the transverse thoracic plane
This is different from the supine position where it lies superior.
What is mediastinoscopy used for?
To view or biopsy mediastinal lymph nodes
This helps determine if cancer cells have metastasized.
What can cause widening of the mediastinum?
Trauma, malignant lymphoma, hypertrophy of the heart
Widening may be observed in chest radiographs.
What is the surgical significance of the transverse pericardial sinus?
Allows passage of surgical instruments around major vessels
Important for procedures like coronary artery bypass grafting.
What is pericarditis?
Inflammation of the pericardium
It usually causes chest pain and may create a pericardial friction rub.
What condition is characterized by fluid accumulation in the pericardial cavity?
Pericardial effusion
This can lead to cardiac tamponade if severe.
What is cardiac tamponade?
Heart compression due to fluid in the pericardial cavity
It limits the heart’s ability to expand and fill, reducing cardiac output.
What is hemopericardium?
Blood in the pericardial cavity
It can result from myocardial infarction or trauma.
What is pericardiocentesis?
Drainage of fluid from the pericardial cavity
It is performed to relieve cardiac tamponade.
What anomaly is characterized by the heart being positioned on the right instead of the left?
Dextrocardia
It may be associated with situs inversus or isolated cardiac anomalies.
What does the mediastinum contain?
All thoracic viscera except the lungs
It is the central compartment of the thoracic cavity.
What is the function of the fibrous pericardium?
Holds the heart in position and limits its expansion
It is inelastic and attached to surrounding structures.
What is the serous pericardium?
Lining of the fibrous pericardium and exterior of the heart
It allows free movement of the heart during contractions.
What is the role of the pericardial space?
It allows the heart to expand and contract without restriction
The pericardial space can be compromised by fluid or a tumor.
What lines the fibrous pericardium and the exterior of the heart?
The serous pericardium
It provides a lubricated surface for the heart’s movement.
What does the serous pericardium allow the heart to do during contraction?
Free movement required for its ‘wringing-out’ motions
This movement is crucial for effective heart function.
Which layer of the serous pericardium is sensitive to pain?
The parietal layer
It conducts pain impulses through the somatic phrenic nerves.
What type of sensations result from pain impulses conducted by the parietal layer of the serous pericardium?
Referred pain sensations
This can lead to confusion in diagnosis of heart-related issues.
