Mediastinum

Question 1

بسم الله الرحمن الرحيم وبه نستعين
توكلنا علي الحي الذي لايموت \
Define mediastinum ,

Answer 1

It is occupied by the mass of
tissue between the two
pulmonary cavities

Question 2

The mediastinum in living

people is a highly mobile region, WHY? `

Answer 2

because it consists primarily of
hollow visceral structures united
only by loose connective tissue.

Question 3

Boundaries:Mediastinum

Answer 3

▪ Anteriorly: the sternum 
and costal cartilages. 
▪ Posteriorly: the bodies 
of all thoracic vertebrae. 
▪ Superiorly: the plane 
of the thoracic inlet.
▪ Inferiorly: the 
diaphragm.

Question 4

▪ The mediastinum is divided by an imaginary plane (extending from the ؟؟ to the ؟)
into:
1) Superior mediastinum: which lies superior to the imaginary plane.
2) Inferior mediastinum: lying between the imaginary plane and the diaphragm.

Answer 4

sternal angle To lower border of the 4th thoracic vertebra

Question 5

▪ Inferior mediastinum is further subdivided by the

pericardium and heart into:

Answer 5

1. Anterior mediastinum: anterior to the pericardium and heart.
2. Middle mediastinum: formed of the pericardium and the heart.
3. Posterior mediastinum: located posterior to the pericardium and heart.

Question 6

Boundaries : of superior Mediastinum

Answer 6

▪ Anteriorly: back of the manubrium sterni.

▪ Posteriorly: the upper 4 thoracic vertebrae.

▪ Superiorly: the plane of the thoracic inlet.

▪ Inferiorly: the imaginary horizontal plane extending from the sternal angle anteriorly to the lower border of T4 vertebra posteriorly. It is also called the transverse thoracic plane.
▪ On each side: The pleura and
lung

Question 7

Superior mediastiunim from the anterior to posterior contains?

Answer 7

Muscles
Remenants of thymus
Arterires
veins
Nerves and nerve pleuxses
Viscera
Thoraci duct

Question 8

Muscels in superior mediastiumn ?

Answer 8

Sternohyoid

sternothyroid

Question 9

Veins

Answer 9

Rigth and left brachicephalich

and upper 1/2 of SVC

Question 10

Arteris in superior mediastium ?

Answer 10

Arch of Aorta
Brachicephalich trunk
left common carotid
left subclavian

Question 11

Nerves of superior mediastiunm ?

Answer 11

Vagus
Phrenic
Cardic plexu

Question 12

Viscera related to Superior Mediastiuim ?

Answer 12

Trachea

Esophaugus with Reucrrent Laryngeal Nerve

Question 13

Anterior Medistiunm Boundaries?

Answer 13

Boundaries 
▪ Anteriorly: Body of the sternum. 
▪ Posteriorly: The pericardium. 
▪ Superiorly: is continuous with the superior mediastinum at he level of sternal angle. 
▪ Inferiorly: The diaphragm. 
▪ On each side: The pleura 
and lung.

Question 14

Contents
▪ It contains loose connective tissue, fat, lymph vessels and lymph nodes.
▪ It also contains the following
structures:

Answer 14

a) Remnants of thymus in the upper part down to the 4th costal cartilage.
b) The superior and inferior sternopericardial ligaments which connect the front of the
pericardium and back of the body
of the sternum.

c) Mediastinal branches of internal thoracic artery.

Question 15

Thymus ?

Answer 15

▪ It is located in the inferior part of the neck and the anterior part of the superior mediastinum and extends into the anterior mediastinum where m it lies posterior to the manubrium and, anterior to the fibrous pericardium

Question 16

▪Thymus, It is well developed during fetal and early post-natal life (childhood).
▪ It reaches its maximum size in the??? and remains so until
puberty after which it gradually involutes and becomes largely replaced
by fat and fibrous tissue

Answer 16

2nd year after birth

Question 17

Arterial supply of Thymus?>

Answer 17

Anterior intercostal arteries

Anterior Mediastinal branches of internal Thoracic Artery

Question 18

Veins of Thymus ends in ?

Answer 18

1-Left brachiocephalic

2-Internal throacic

3-inferior Thyroid

Question 19

Lymphatic vessels of Thymus?

Answer 19

Parasternal LN
Brachiocephalic LN
TracehoBronchial LN

Question 20

Middle Mediastiunm?

Answer 20

Percardium and Heart

Arteris: Ascending Aorta +Pulmonary trunk – 2 pulmonary arteris
Veins: Lower SVC and terminal azyogus - upper IVC + Pulmonary veins
Bifuraction of Trachea into 2 Bronchi + Phrenic Nerve + pericardiophrenic arteries

Question 21

Boundaries of Posterior Mediastiunm/

Answer 21

▪ Posteriorly: The lower 8 thoracic vertebrae (T5 - T12)

Question 22

Posterior Mediastium contents?

Answer 22

Arterirs : Descending Thoracic aorta + Posterior intercostal arteries
Veins : azygous + hemiazygous +accessory Hemiazygous
Lymph: Thoracic duct + posterior mediastinal LN
Nerrves: Splanchinc nerves greater lesser lowest
Viscera: Ospehagus osophageal pleusx of nerves شكرا!

Question 23

❑ Mediastinitis may occur GR?

Answer 23

due to spread of deep infection of the neck into the thorax.

Question 24

❑ Compression on the vital structures of the mediastinum may
occur due to:

Answer 24

➢Tumour of the lung with enlarged mediastinal lymph nodes.

➢Aortic aneurysm.

Question 25

``` ❑ Compression of the following structures leads to: ➢SVC → ➢Left recurrent laryngeal nerve → ➢Trachea and main bronchi → ➢Oesophagus → ➢Phrenic nerve → ```

Answer 25

Severe engorgement of the veins of the upper part of the body. Hoarseness of the voice. Dyspnea (difficulty in breathing). Dysphagia (difficulty in swallowing). Hemidiaphragm (paralysis of the corresponding side of the diaphragm).