The Mediastinum

Question 1

what separates the superior mediastinum from the inferior mediastinum

Answer 1

the superior mediastinum is above the angle of louis (line between sternal angle {where manubrium joins body} and bottom of T4 vertebrae)

anything below angle of louis is INFERIOR mediastinum. The inferior mediastinum is split into (anterior, middle and posterior mediastinum= these refer to there position in relation to the heart)

Question 2

what anatomical features are within the superior mediastinum

Answer 2

Superior Mediastinum:
Organs: trachea, esophagus.
Arteries: aortic arch, brachiocephalic trunk, left common carotid artery, left subclavian artery.
Veins; left and right brachiocephalic veins {these drain into superior vena cava}, azygous vein
Nerves: left and right vagus nerves, left and right phrenic nerves

Question 3

where is the thymus (only present in children, disappears at puberty) located in mediastinum

Answer 3

thymus is located in anterior mediastinum

Question 4

bifurcation of trachea (T4/T5 vertebral level) and the heart, as well as the continuation of the left and right phrenic nerves is in what part of mediastinum?

Answer 4

middle mediastinum is where the bifurcation of trachea (T4/T5 vertebral level; it bifurcates at the sternal angle/angle of louis/manubriosternal joint) and the heart, as well as the continuation of the left and right phrenic nerves sit

Question 5

what is within the posterior mediastinum

Answer 5

posterior mediastinum contains the
* sympathetic trunks (T1 to L2/3.)
*azygous venous system (receives blood from accessory hemiazygous + hemiazygous veins)
* thoracic duct (carries lymphatic fluid)
*thoracic aorta T4-T12 (provides small branches to bronchi, oesophagus and diaphragm)
*oesophagus travelling all the way through thorax to the stomach

Question 6

what vertebral level does the aorta bifurcate

Answer 6

abdominal aorta bifurcates at the level L4 into the right and left common iliac arteries, which supply the pelvis and lower extremities

n.b. aorta becomes abdominal aorta at T12 vertebral level and continues down till L4 where it bifurcates

Question 7

what vertebral level are the following structures located at :
*bifurcation of common carotid artery (CCA)
*thyroid cartilage
*cricoid cartilage
*arch of aorta
*xiphoid process
*transpyloric plane
*origin of renal artery
*subcostal plane
*bifurcation of abdominal aorta
*transtubercular plane
*formation of IVC (inferior vena cava)

Answer 7

*bifurcation of common carotid artery (CCA)= C3 {n.b. CCA has 3 letter}

*thyroid cartilage= C5

*cricoid cartilage= C6

*arch of aorta= T4

*xiphoid process= T9

*transpyloric plane=L1

*origin of renal artery= L2

*subcostal plane= L3

*bifurcation of abdominal aorta= L4

*transtubercular plane= L5
*formation of IVC (inferior vena cava)= L5

Question 8

what vertebral level does the oesophagus begin and end at

Answer 8

The esophagus (oesophagus) is a 25 cm long fibromuscular tube

extending from the pharynx (C6 level) to the stomach (T11 level)