mediastinum Flashcards
Occupied by the mass of tissue between the two pulmonary cavities
mediastinum
Central compartment of the thoracic cavity
mediastinum
Covered on each side by mediastinal pleura and contains all the thoracic viscera and structures EXCEPT the lungs
mediastinum
which boundary of the mediastinum is the superior thoracic aperture
superiorly
which boundary of the mediastinum is the diaphragm
inferiorly
which boundary of the mediastinum is the pleural cavities
laterally
which boundary of the mediastinum is the sternum and costal cartilages
anteriorly
which boundary of the mediastinum is the thoracic vertebrae
posteriorly
Extends inferiorly from the superior thoracic aperture to the horizontal plane that includes the sternal angle anteriorly and passes approximately through the junction (IV disc) of T4-T5 vertebrae posteriorly, often referred to as the transverse thoracic plane (imaginary line)
superior mediastinum
Between the transverse thoracic plane and the diaphragm
inferior mediastinum
the inferior mediastinum is further subdivided into
anterior, middle, posterior
includes pericardium, heart, and roots of its great vessels (ascending aorta, pulmonary trunk, SVC)
middle mediastinum (inferior)
A fibroserous membrane that covers the heart and the beginning of its great vessels
pericardium
pericardium has two layers
fibrous and serous
Tough fibrous membrane that covers the heart and the origin of the great vessels (arteries: pulmonary artery and the aorta)
fibrous pericardium
Avoids overdistension of the heart
fibrous pericardium (function)
Prevents sudden overfilling of the heart
fibrous pericardium (function)
Continuous superiorly with the tunica adventitia of the great vessels entering and leaving the heart and with the pretracheal layer of deep cervical fascia
superior continuation of the fibrous pericardium
Attached anteriorly to the posterior surface of the sternum by the sternopericardial ligaments
anterior continuation of the fibrous pericardium
Bound posteriorly by loose connective tissue to structures in the posterior mediastinum
posterior continuation of the fibrous pericardium
Continuous inferiorly with the central tendon of the diaphragm by the pericardiacophrenic ligament
inferior continuation of the fibrous pericardium
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
serous pericardium
Lines the inner surface of the fibrous pericardium
parietal layer of the serous pericardium
Forms the outer layer (epicardium) of the heart wall and the roots of the great vessels
visceral layer of the serous pericardium
Is a potential space between opposing layers of the parietal and visceral layers of serous pericardium
pericardial cavity
Because of the lining, we will be able to appreciate that there are two potentialspaces at the back of the heart
pericardial sinuses
Posterior to the intrapericardial parts of the pulmonary trunk and ascending aorta, anterior to the SVC and superior to the atria of the heart
transverse pericardial sinus
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
mesothelium
While performing surgery on the aorta or pulmonary artery, a surgeon can pass a finger and make a ligature through the sinus between the arteries and veins, thus stopping the blood circulation with the ligature
transverse pericardial sinus
Between the great arteries
transverse pericardial sinus
Pericardial reflections of the PVs and IVC laterally
Oblique pericardial sinus
Wide pocket-like recess in the pericardial cavity posterior to the base (posterior aspect) of the heart, formed by the left atrium
Oblique pericardial sinus
BLOOD SUPPLY OF PERICARDIUM
pericardiophrenic artery
musculophrenic artery
bronchial, esophageal, and superior phrenic arteries
coronary arteries
main arterial supply of the pericardium
pericardiophrenic artery
Arterial supply to the pericardium, branches of the internal thoracic artery (ITA)/ internal mammary artery (IMA)
pericardiophrenic artery
a branch coming from the subclavian artery
internal thoracic artery (ITA)/ internal mammary artery (IMA)
Often accompanies or at least parallels the phrenic nerve to the diaphragm
pericardiophrenic artery
Terminal branch of the ITA
musculophrenic artery
Branches coming from the anterior wall of the descending thoracic aorta; At the back of the pericardium
Bronchial, Esophageal, and Superior phrenic arteries
supplies the visceral layer of the pericardium only; The first branches of the aorta
coronary arteries
venous drainage of the pericardium
pericardiophrenic veins
Variable tributaries of the azygos venous system
Tributaries of the brachiocephalic (or internal thoracic) veins
Pericardiacophrenic veins
Drain directly to the brachiocephalic (innominate vein) or sometimes it can drain directly into the branches that comes along with the internal thoracic artery
Pericardiacophrenic veins
nerve supply of the pericardium
phrenic nerve (C3-C5)
vagus nerve
sympathetic trunks
Primary source of sensory fibers of the pericardium
phrenic nerve (C3-C5)
Pain sensations conveyed by these nerves are commonly referred to the skin (C3–C5 dermatomes) of the ipsilateral supraclavicular region (top of the shoulder of the same side)
phrenic nerve (C3-C5)
vasomotor of the pericardium
sympathetic trunks
A phenomenon whereby noxious stimuli originating from a structure are perceived as pain arising from a superficial part of the body
referred pain
Supraclavicular area (C3-C5)
Pain sometimes at the level of the shoulder
pericardial involvement
Chest and arm (T1-T4)
T1 - T3 (Moore’s)
Chest pains, back, arm
heart/cardiac pain
pain in the back
MI
Superior to the transverse thoracic plane, passing through the sternal angle and the junction (IV disc) of vertebrae T4 and T5
superior mediastinum
includes (from anterior to posterior):
Thymus
Great vessels, with the veins anterior to the arteries and related nerves
Inferior continuation of cervical viscera and related
nerves
Thoracic duct and lymphatic trunks
superior mediastinum
veins of superior mediastinum
Brachiocephalic
SVC
arteries of superior mediastinum
Arch of aorta and roots of its major branches
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
nerves of superior mediastinum
Vagus nerve
Phrenic nerve
Cardiac plexus of nerves
cervical viscera
Anterior: trachea
Posterior: esophagus
related nerves in the inferior continuation of cervical viscera
Left recurrent laryngeal nerves
Traverses the superior mediastinum
Thoracic duct and lymphatic trunks
the order of the majorstructuresin the superior mediastinum, from anterior to posterior,
(1) thymus, (2) veins, (3) arteries, (4) airway, (5) alimentary tract, and (6) lymphatic trunks
Primary lymphoid organ at the inferior part of the neck and anterior to the superior mediastinum
thymus
Flat gland with flask-shaped lobes that lies posterior to the manubrium and extends into the anterior mediastinum, anterior to the fibrous pericardium
thymus
After puberty → involution and replaced by fat
thymus
For pediatric patients, are relatively bigger compared to adults, in adults replaced by fatty tissue
thymus
arterial supply of thymus
Derived mainly from:
Anterior intercostal arteries
Anterior mediastinal branches of the ITA/IMA
venous drainage of thymus
End in the left brachiocephalic, ITA/IMA, and inferior thyroid veins
lymphatic vessels of thymus
End in the parasternal, brachiocephalic, and tracheobronchial lymph nodes
great vessels
brachiocephalic
SVC
ascending aorta
aortic arch
The right and left _____ are formed posterior to the sternoclavicular (SC) joints by the union of the internal jugular and subclavian veins
brachiocephalic veins
At the level of the inferior border of the 1st right costal cartilage, the _____ unite to form the SVC
brachiocephalic veins