ميحرلا نمحرلا الله مسب the mediastinum · dr.shireen anatomy (thorax) 24/4/2012...
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24/4/2012 Anatomy (Thorax) Dr.shireen
1
بسم هللا الرحمن الرحيم
The Mediastinum
Today, we will take the contents of the mediastinum.
We will divide the contents of the mediastinum
in two aspects:
1- From Posterior to Anterior (for The
Superior mediastinum)
2-From Superior to Inferior.
:Posterior to Anterior From 1)
Posterior Middle Anterior
(Tubal layer) (Arterial layer) (Venous layer)
Tubal layer :
It has two contents: 1- Esophagus
2-Trachea
1) Esophagus (A Revision):
Length: 10 inches (25 cm).
Origin: It starts as a continuation
of the Pharynx (بلعوم ) in The
lower Border of C6 (Important
landmark).
24/4/2012 Anatomy (Thorax) Dr.shireen
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Shape: Muscular Tube.
Site: It's divided into two parts; the first one is in
the Superior mediastinum and the second is in the
Inferior mediastinum (Posterior part).
End: It passes through a special opening in The
Diaphragm and then continues as a stomach.
Relations:
The Right side: Related to the right lung
(makes an impression on the right lung) .
The Left side: - it makes an impression on the
left lung at the upper part ( superior
mediastinum) .
- Left to the Esophagus
at thoracic aorta DescendingThe there is
.the inferior mediastinum
Anterior: -There is The Trachea at the superior
mediastinum .
-There is The Heart at the Inferior
mediastinum.
Posterior: There is the vertebral column.
Blood Supply: The Aorta.
Note: Any content in the Mediastinum takes The
Arterial supply from The Aorta.
24/4/2012 Anatomy (Thorax) Dr.shireen
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2) Trachea:
Length: 10 cm.
Origin: starts as a continuation of Larynx (الحنجرة)
in the lower Border of C6 (important landmark).
Site: It's considered to be a content of Superior
mediastinum because it ends at the line between
Superior and Inferior mediastinum.
Relations:
Anterior: There is The Arch of The Aorta.
Posterior: There are Esophagus and the Vertebral
column.
The Right side: Related to the right lung (It makes
an impression on the right lung).
Left Side: There is The Aortic Arch so it doesn’t
make any impression on the left lung.
Note: The Aortic Arch has Double Relations with The
Trachea; Firstly, It is Anterior to The Trachea Then it
turns to the left side of
Trachea.
End: it Makes a
Bifurcation (تشعب) and
gives Two Bronchi;
Left & Right, at The
Line between The
Superior and Inferior
mediastinum.
24/4/2012 Anatomy (Thorax) Dr.shireen
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Note: The differences below can't be distinguished in the
picture but they are true.
Left bronchus Right bronchus
Longer Shorter Length Narrower Wider Width Makes an Obtuse angle (135o)
Continuation of Trachea(in the same direction)
Orientation
___________
Divides into two Branches before it enters The Hilum of the right lung
Divisions
Note: Because of The divisions of the right bronchus, we
found the bronchus in the right hilum divided into Eparterior
and Hyparterior.
Clinical Application:
**Suppose that you are in the Emergency Section, and a child
( ( Inhaled Foreign Body) كة أو غطا ألم مسلا شرق في أست (
-This Body will enter easily to the Right Bronchus because
it's a continuation of Trachea, wider and shorter.
:Remember These landmarks
24/4/2012 Anatomy (Thorax) Dr.shireen
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Arterial Layer: ((We have just one artery
(The Aorta).)) The Aorta starts as the Ascending aorta which
comes from the left ventricle, and then the
ascending aorta converts to The Arch of the
Aorta then to the descending Aorta.
The Descending Aorta divides into two parts;
the first (Descending thoracic Aorta) inside
the Thorax, and the other part (Descending
Abdominal Aorta) enters the Abdomen through
the diaphragm.
**Now we will take origin, end and branches of each
part of The Aorta.
1) The Ascending Aorta :
Origin: starts from the left ventricle posterior to
the pulmonary trunk.
It is Directed Anterior (Forward).
End: In the Line between the Superior and
Inferior mediastinum.
Branches: Gives two Branches (Right & Left
coronary arteries).
2) The Arch of Aorta:
Origin: Starts as a continuation of the
Ascending Aorta at The level of Sternal Angle
directed anteriorly.
24/4/2012 Anatomy (Thorax) Dr.shireen
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Then It's Directed Posterior (backward).
End: At the Same Level where It starts
(between T4 and T5).
Branches:
Left common carotid artery
Left Side (It goes to the Head & Neck).
Left Subclavian Artery
(It goes to the left Upper Limb).
Right Common carotid
Right Side Brachiocephalic (To the Head & Neck)
Right Subclavian artery
(To the Right Upper limb).
o Right Subclavian
&carotid artery both
branch from
Single Trunk
(Brachiocephalic).
24/4/2012 Anatomy (Thorax) Dr.shireen
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o There are Two impressions (grooves) for the left
common carotid (anterior) and left subclavian
(posterior) in the left lung.
3) The Descending Thoracic Aorta:
Origin: Starts as a continuation of the arch
between T4 & T5, and then continues in the
Inferior mediastinum (Posterior part).
End: It passes through a special opening in the
diaphragm and continues as Abdominal Aorta.
Branches :
Paired Single
-Post. Intercostals -Fibrous Pericardial
-Bronchial - Mediastinal
-Subcostal -Esophageal
-Phrenic
Venous Layer:
o The Right and the left side are Nearly the same.
24/4/2012 Anatomy (Thorax) Dr.shireen
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o Right internal Jugular and Right subclavian unite to
make Right Brachiocephalic.
Note: The left side has the same veins.
o The Difference between The two sides:
- Right Brachiocephalic is shorter than left
Brachiocephalic because the left one crosses the
midline from left to right side but the right
brachiocephalic stays in the right side (Look at
the picture).
o Finally, the right &
left brachiocephalic
veins unite opposite
to the right first
costal cartilage to
give the Superior
Vena Cava.
The Superior Vena
Cava (SVC) :
o Takes the venous drainage from Head, Neck
and Upper limbs.
Origin: Starts as a union of right and left
brachiocephalic veins opposite the right first
costal cartilage.
Length: 3 inches.
Course: passes in the Superior mediastinum
then in the Inferior (Middle mediastinum).
24/4/2012 Anatomy (Thorax) Dr.shireen
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End: In the 3rd costal cartilage and drains in
the right atrium.
o There is a tributary (Azygos vein) exactly in the
middle of (SVC) (2nd costal cartilage).
Now, we will take the contents of the mediastinum
from Superior to inferior:
2) From Superior to Inferior:
Superior
mediastinum:
Esophagus
Trachea
Arch of aorta and its
big branches (Brachiocephalic,
left common carotid
and left subclavian)
Brachiocephalic
veins
Upper Half of Superior Vena Cava
24/4/2012 Anatomy (Thorax) Dr.shireen
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Inferior mediastinim:
Middle part:
The Heart –the fibroserous sac surrounding it
(pericardium).
-The vessels entering the heart (lower half
of SVC & upper half of IVC).
-The vessels leaving the heart (pulmonary
trunk & Ascending Aorta)
Posterior part:
Esophagus
Descending Thoracic Aorta
Azygos and hemiazygos veins
The impressions in the
medial surface of lung:
(Important for the lab)
Right lung: (look at the
picture).
Esophagus (most
posterior)
Trachea
Rt. Brachiocephalic
vein & SVC
Cardiac impression(right atrium)
24/4/2012 Anatomy (Thorax) Dr.shireen
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Left lung: (Look at the
picture).
Aorta (Arch and
descending Aorta)
Esophagus
Left subclavian
Left common carotid
artery
Cardiac
impression(left
ventricle)
وحنبدا االسبوع الجاي ان شاء هللا في ال Thoraxوكدا دحنا خلصنا ال
Abdomen.
The more you can dream, the more can you do,
So make your dreams infinite.
With my best wishes,
Your colleague: Mohannad Abo Hamad
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