Heart Anatomy I and II Flashcards
What are the superior, inferior, anterior, and posterior borders of the mediastinum?
Superior = superior thoracic aperture
Inferior = diaphragm
Anterior = sternum + costal cartilages
Posterior = thoracic vertebrae
The inferior mediastinum is subdivided by the ___________ into 3 parts
Pericardium
The inferior mediastinum is subdivided by the pericardium into anterior, middle, and posterior parts. What structures are found in the middle subdivision?
Pericardium and its contents = heart, ascending aorta, pulmonary trunk, SVC
Is it possible for structures to exist in more than one mediastinal compartment?
Yes, some structures like the esophagus pass vertically and lie in more than one mediastinal compartment
The pericardium covers the heart and beginnings of the great vessels. It is a closed sac composed of what 2 major layers?
Fibrous pericardium = tough external layer
Serous pericardium = composed mainly of mesothelium (single layer of flattened cells)
The fibrous pericardium is continuous with the _____ _____ of the diaphragm. The internal surface is lined with a parietal layer of _______ pericardium, which is also reflected onto the heart at the great vessels.
Central tendon; serous
The fibrous pericardium is continuous superiorly with what 2 layers of named connective tissue?
- Tunica adventitia (perivascular connective tissue of great vessels entering and leaving the heart)
- Pretracheal layer of deep cervical fascia
The fibrous pericardium is attached anteriorly to the posterior surface of the sternum by what structures?
Sternopericardial ligaments (which are highly variable in their development)
The fibrous pericardium is bound posteriorly by _____ _______ to structures in the ______ ______
Loose CT; posterior mediastinum
The fibrous pericardium is continuous inferiorly with the central tendon of the diaphragm. What ligament forms the site of continuity?
Pericardiacophrenic ligament
[however, note that fibrous pericardium and central tendon are NOT separate structures that fused together secondarily, nor are they separable by dissection]
Overall, what connections are involved in tethering the heart inside the fibrous pericardium?
Tunica adventitia, pretracheal layer of deep cervical fascia, sternopericardial ligaments, loose connective tissue, and pericardiacophrenic ligament connecting to the central tendon of the diaphragm
The serous pericardium is composed mainly of mesothelium - a single layer of flattened cells forming an epithelium that lines both the internal surface of the fibrous pericardium and the external surface of the heart. What are the 2 layers of the serous pericardium?
Visceral layer - forms the epicardium (outermost layer of the heart wall)
Parietal layer - where the aorta and pulmonary trunk leave the heart, and where the SVC, IVC, and pulmonary veins enter
Where do the visceral and parietal layers of serous pericardium become continuous?
At the beginning of the great vessels
What provides the main arterial supply to the pericardium?
Pericardiacophrenic a. (slender branch of internal thoracic a.)
The main arterial supply to the pericardium is the pericardiacophrenic a., which is a slender branch of the ______ ______ artery and often accompanies the _______ nerve to the diaphragm
Internal thoracic
Phrenic
The main arterial supply to the pericardium is the pericardiacophrenic a.. What arteries provide smaller contributions?
Musculophrenic a. (Terminal branch of internal thoracic a.)
Bronchial, esophageal, and superior phrenic aa. (Branches of thoracic aorta)
Coronary aa. (First branches of aorta; supply visceral layer of pericardium only!)
Smaller contributions to the arterial supply of the pericardium include the following:
Musculophrenic a.
Bronchial, esophageal, and superior phrenic aa.
Coronary aa.
What arteries do the above branch off of?
Musculophrenic - internal thoracic a.
Bronchial, etc. - thoracic aorta
Coronary aa. - aorta (remember only supplying visceral pericardium)
What provides venous drainage of pericardium?
Pericardiacophrenic veins (tributaries of the brachiocephalic or internal thoracic vv.)
Variable tributaries of the azygous venous system
The pericardiacophrenic veins provide venous drainage to the pericardium. What are these veins tributaries of?
Brachiocephalic or internal thoracic veins
What nerves provide innervation to the pericardium?
Phrenic nerves (C3-5)
Vagus nn.
Sympathetic trunks
Innervation to the pericardium is provided by the phrenic nerves, vagus nerves, and sympathetic trunks. Which of those is the primary source of sensory fibers?
Phrenic nerves (C3-C5)
Pain sensations conveyed are commonly referred to skin (C3-5 dermatomes) of ipsilateral supraclavicular region
Innervation to the pericardium is provided by the phrenic nerves, vagus nerves, and sympathetic trunks. The phrenic nerves are the primary source of sensory innervation. What are the functions of the other 2?
Vagus nerves - function uncertain
Sympathetic trunks - vasomotor
What structure, found posterior to the intrapericardial parts of the pulmonary trunk and ascending aorta, anterior to the SVC, and superior to the heart atria, forms a passage within the pericardial cavity between 2 groups of vessels and the reflections of serous pericardium surrounding them?
Transverse pericardial sinus
The transverse pericardial sinus forms a transversely running passage within the pericardial cavity between what 2 groups of vessels (and the reflections of serous pericardium surrounding them)?
- Aorta and pulmonary trunk
2. SVC, IVC, pulmonary veins