Mediastinum Flashcards
The mediastinum is the…
central compartment of the thoracic cavity.
The mediastinum is occupied by…
the mass of tissue between the two pulmonary cavities.
What covers the mediastinum on each side?
Mediastinal pleura
What does the mediastinum contain?
All thoracic visera and structures, except lungs
Superior boundary of mediastinum
Superior thoracic aperture
What is the other name for the superior thoracic aperture?
Thoracic inlet
The superior thoracic aperture is bounded by which structures (3)?
Manubrium, 1st pair of ribs, anterior surface of body of T1
What is the landmark for the superior thoracic aperture?
Anterior sternal notch
Mediastinoscopy
a surgical procedure to examine the inside of the upper chest between and in front of the lungs (mediastinum); CT scan is more preferred now
Inferior boundary of mediastinum
Diaphragm, lower portion of sternum
Anterior boundary of mediastinum
Sternum and costal cartilages
Posterior boundary of mediastinum
Bodies of thoracic vertebrae
Lateral boundary of mediastinum
Mediastinal pleura
Major structures in mediastinum are surrounded by…
Blood, lymphatic vessels and nodes, nerves, and fat
Why is the mediastinum highly mobile?
Because it consists primarily of hollow visceral structures united only by loose connective tissue, often infiltrated by fat.
The mediastinum is a highly pliable and dynamic structure moved by:
structures within and surrounding it; the gravity and different body positions
The ___________ of CT and _________ of the lungs and parietal pleura on its sides accommodate movement and volume and pressure changes in thoracic cavity.
looseness; elasticity
Example of movement and volume and pressure changes in the thoracic cavity:
Respiration: movements of diaphragm, thoracic wall, and tracheobronchal tree
Circulation: contraction of heart, pulsation of arteries
Digestion: passage of food through esophagus
What happens to the connective tissue in the mediastinum with age?
More fibrous and rigid = less mobile
The mediastinum is divided into which parts?
superior and inferior parts
What is the anterior boundary of the superior mediastinum?
Manubrium of sternum
What is the posterior boundary of the superior mediastinum?
Anterior surface of the bodies of T1-T4 and corresponding IV disks
What is the superior boundary of the superior mediastinum?
Superior thoracic aperture
What is the inferior boundary of the superior mediastinum?
Transverse thoracic plate
What is the transverse thoracic plate?
Horizontal plane from IV disc of T4-T5 to the sternal angle of Louis
What are the contents of the superior mediastinum (A to P)?
- Thymus
- Great vessels: veins (left and right brachiocephalic veins and superior vena cava) and arteries (arch of aorta and its branches, right branchiocephalic trunk, left common carotid artery, left subclavian artery)
- Phrenic and vagus nerves; cardiac plexus of nerves
- Trachea and esophagus (+ left recurrent laryngeal nerve)
- Thoracic and lymphatic trunks
What is the enlarged thyroid from the neck that sometimes goes down to the mediastinal compartments?
Goiter
What is a primary lymphoid organ for development and maintenance of
the immune system?
Thymus
