Organization of the thorax: Wilson Flashcards
The sternal angle is an important landmark for what?
- manubriosternal joint
- 2nd rib
- vertebral level T4-T5
The thorax can be divided into what 3 cavities?
- left and right pleural cavities holding the lungs
- the mediastinum holding the heart
What is the superior boundary of the mediastinum?
superior thoracic aperture
What is the inferior boundary of the mediastinum?
inferior thoracic aperture whose space is bounded by the diaphragm
What is the anterior boundary of the mediastinum?
sternum
What is the posterior boundary of the mediastinum?
thoracic vertebrae
What is the lateral boundary of the mediastinum?
pleura
A line running from the sternal angle to T4-5 divides the mediastinum into what?
superior and inferior mediastinum
What further divides the inferior mediastinum into the anterior, posterior, and middle mediastinum?
pericardial sac
How does the mediastinal viscera position shift from a supine to standing position?
the heart is located more inferiorly when standing than when in supine position
Where is the location of the thymus in relation to the sternum?
thymus is found immediately beneath the sternum
In the adult , the thymus gland usually undergoes what process?
involution to fat
histologically, fragments of thymus remain within the fat throughout life
What are the great veins that are found in the superior mediastinum?
left and right brachiocephalic vein that come together to form the superior vena cava
Which part of the mediastinum is the superior vena cava located in?
superior vena cava is located primarily in the superior mediastinum with its distal portion located in the middle mediastinum
What arteries are located in the superior mediastinum?
arch of the aorta
What are the direct branches of the arch of the aorta?
- brachiocephalic trunk (which will branch into right subclavian and right common carotid artery)
- left common carotid artery
- left subclavian artery
What nerve runs along the lateral border of the superior vena cava?
phrenic nerve
What nerve passes posterior to the ligamentum arteriosum and provides innervation to the esophagus, trachea, and larynx?
left recurrent laryngeal nerve which is a branch of the left vagus nerve
What is the embryological form of the ligamentum arteriosum?
ductus arteriosus
Explain how dysphonia be a sign of an aortic aneurysm.
The left recurrent laryngeal nerve passes posterior to the ligamentum arteriosum which is in between the aortic arch and left pulmonary artery. The enlarged aortic arch could compress this nerve which provides innervation to the larynx.
What does the right recurrent laryngeal nerve wrap around before ascending to innervate the larynx?
the right subclavian artery
Why are the courses of the left and right recurrent laryngeal nerve different in the adult?
because they have differential development of the right and left 4th aortic arches
Where does the trachea bifurcate? Which portion of the mediastinum is it located in?
- bifurcates at the sternal angle
- thus the bronchi are not in the mediastinum