mediastinum

Question 1

where does the remenant of the thymus lie?

Answer 1

in the retromanubral layer

Question 2

what is the contents of the mediastinal venous layer?(3)

Answer 2

• Rt and Lt brachiocephalic
• upper part of the SVC
• RTphrenic nerve

Question 3

what is the contents of the mediastinal arterial layer?

Answer 3

. Arch of the aorta and its branches.

• Bifurcation of pulmonary trunk.
• Ligamentum arteriosum.
• Lt vagus and Lt pherenic
• Lt recurrent laryngeal nerve.

Question 4

what is the contents of the mediastinal tubal layer?

Answer 4

. Trachea.

• esophagus.
• Rt vagus.
• Thoracic duct
• Tracheobronchial LNs

Question 5

what is the contents of the mediastinal prevertebral layer?

Answer 5

. Sympathetic chain.

• Azygos vein.
• Longus coli muscle.

Question 6

what is the contents of the anterior mediastinum?

Answer 6

1. Remains of thymus
2. Superior and inferior sternopericardial ligaments
3. Mediastinal branches of internal thoracic artery

Question 7

what is the contents of the middle mediastinum?

Answer 7

Pericardium & the structures inside it

Question 8

what is the contents of the posterior mediastinum?

Answer 8

A. Descending thoracic aorta.
B. Oesophagus.
C. Thoracic duct.
D. Rt and Lt Vagi.
E. Rt and Lt Sympathetic chains.
F. Azygos, sup. Hemiazygos &
inf. Hemiazygos

Question 9

what is the course of the thoracic duct?(beginning and termination)

Answer 9

it starts at the upper end of cisterna chyli at the upper border of the t12 goes to the opposite side(left) at t5

it ends at the root of the neck in the angle formed by the junction of the left subclavian and the internal jugular vein

Question 10

what is the sympathetic trunk?

Answer 10

it is the sympathetic ganglia and the communications between them

Question 11

how many ganglia does the sympathetic trunk contain?

Answer 11

12

Question 12

the 1st thoracic ganglia may be fused with the cervical one forming?

Answer 12

stellate ganglion

Question 13

thoracic sympathetic trunk and it’s nerves?(3)

Answer 13

1-greater splanchnic (T5-T9)
2-lesser splanchnic (T10-T11)
3-least splanchnic (T12)

Question 14

what is horner syndrome?

Answer 14

t is due to injury of sympathetic chain

Question 15

what is the symptoms of the horner syndrome?(4)

Answer 15

1- Ptosis (eyelid drop).
2- Myosis (constriction of the pupil).
3- Anhydrosis
4- Enophthalmos

Question 16

what is the Origin, Termination and branches of the ascending aorta?

Answer 16

begins aortic orifice opposite the 3rd left intercostal
space

ends behind the 2nd right sternocostal junction by
becoming arch of aorta

Branches: Rt and Lt coronaries.

Question 17

what is the Origin and Termination of the aortic arch?

Answer 17

It begins at the 2nd right sternocostal It passes first upwards, backwards and to the left

It ends T4 and T5 by becoming the descending thoracic aorta

Question 18

what is the branches of the aortic arch?

Answer 18

3 large branches:
brachiocephalic, left common carotid and left subclavian arteries

A 4th small branch, the thyroideaima,
may arise from the arch and ascend to supply the thyroid gland

Question 19

what is the Origin, Termination and branches of the descending aorta?

Answer 19

begins disc between T4 and T5 as the continuation of the arch of the aorta

It ends at the lower border of T12, by passing through the aortic opening of the diaphragm to continue as the abdominal aorta.

branches:

1. posterior intercostal arteries (from 3rd to 11th).
2. subcostal arteries.
3. Two left bronchial arteries.
4. Four or five oesophageal branches.
5. Few small twigs to the pericardium, mediastinum and diaphragm

Question 20

Clinically Important Points

Answer 20

1- Coarctation of the aorta: aortic coartication (narrowing) may involve the segment from the left subclavian artery to the ductus arteriosus. The latter remains patent and maintains the circulation to the lower parts of the body.
• If the obstruction is distal to the attachment of the ligamentum arteriosum, the circulation to the lower limb is maintained via collaterals between branches of the subclavian arteries and those of the descending aorta.
• 2- Aortic aneurysm: this is a localized dilatation of aorta which may compress the contents of superior mediastinum causing mediastinal syndrome. Rupture of weakened wall of aortic aneurysm causes severe haemorrhage which is often fatal if surgical intervention is not prompt
• 3- Clinically, embolism of the pulmonary trunk by a blood clot is a common cause of sudden death.

Question 21

revise the vagus nerve in the lec mediastinum

Question 22

what is the root values of the phrenic nerve

Answer 22

Root value : C3, 4 and 5.

Question 23

revise the course of the right phrenic

Question 24

what id the mediastinal syndrome

Answer 24

Compression of mediastinum by a tumor or
inflammatory mass, lymph nodes or retrosternal goiter leads to :
1- dyspnea ( compression of trachea).
2- dysphagia ( compression of esophagus).
3- hoarseness of voice( compression of Lt recurrent
laryngeal nerve).
4- ischemia( compression of aorta)
5- Non-pitting edema( compression of thoracic duct)

Question 25

what is the blood supply of the esophagus

Answer 25

Upper third : inferior thyroid artery
Middle third ; descending thoracic aorta
Lower third : left gastric artery

Venous drainage ; upper third in inferior thyroid vein, middle third in azygous vein & lower third in left gastric vein

Question 26

what is the start of the esophagus?

Answer 26

c6

Question 27

what is the constrictions of the esophagus?

Answer 27

1- at junction with pharynx
2- where aortic arch & left bronchus cross its anterior surface
3- when esophagus passes in diaphragm

Question 28

what is the start and end of the trachea

Answer 28

start in the neck, at the level of the lower border of C6, as a continuation of the larynx.

end n the thorax, at the level of the sternal angle (disc between T4/T5) by dividing into 2 principal bronch

Question 29

Clinically Important Points on Trachea and Bronchi

Answer 29

1. The trachea may be compressed or displaced by enlargement of lymph nodes or arch of aorta.
2. The carina may become wider or distorted (seen by a bronchoscope) if the inferior tracheobronchial lymph nodes are involved in cancer.
3. A foreign body which may enter trachea will pass more commonly to right bronchus because it is wider and more in line with the trachea