April 10, 2012

ANATOMY LECTURE 21

1

Intercostals vessels

Quick revision for intercostals arteries:

In each space there are two anterior intercostals arteries and only one (single)

posterior artery.

Posterior artery :

3-11 intercostals arteries and subcostal are branched from the aorta.

1st posterior intercostal artery and 2nd posterior intercostals artery are branched

from the costocervical which is branched from the subclavian artery.

Anterior artery:

Branched from the internal thoracic (both sides of sternum) which is branched

from the subclavian artery.

Intercostals veins:

They are exactly like arteries.

Anterior:

Will drain in the internal thoracic vein (branch from subclavian vein) which runs

with the internal thoracic artery.

Posterior:

Different from anterior

1- Right side:

There is a venous channel on the posterior wall, called azygos vein.

All the posterior intercostals veins drain in the azygos vein on the

right side.

2- Left side:

There is two veins (each represent a half):

a) Superior hemiazygos.

b) Inferior hemiazygos.

All left posterior intercostals vein drain in the superior and inferior

hemiazygos.

These two veins (superior and inferior) cross the posterior wall to

drain in the azygos vein.

April 10, 2012

ANATOMY LECTURE 21

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Important Note:

The vein, artery, and nerves run in a special order (called VAN) from superior to inferior

Intercostals veinintercostal arteryintercostal nerve. (Called intercostal VAN).

They are lodge in their groove (intercostals groove).

Right posterior intercostals azygos vein

Left posterior intercostals hemiazygos azygos

Question:

You were in the lab, the groove was marked and the question was: identify

the related structure to the marked area (groove)?

Answer: intercostals VAN, from superior to inferior in the same order (vein,

artery, and nerve) lodging in the groove until they reach the anterior aspect).

April 10, 2012

ANATOMY LECTURE 21

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Thoracic cavity

We took the thoracic wall and we talked about the bones, spaces between bones (intercostals

spaces) , muscles and their nerve supply, arterial supply, and venous drain.

Now if we open the thoracic wall we find a cavity, inside this cavity there is:

Two lungs (on both sides).

Mediastinum space.

Mediastinum :

A space (partition) between the two lungs.

Contain the structure that’s go down to the thorax and abdomen and vice versa.

It’s divided into two parts by horizontal line which extends from the sternal angle

(anteriorly) to the intervertebral disc between T4 and T5 (very important land

mark).

Some people say lower border of T4.

Another landmark is the 2nd rib (because the sternal angle has the 2nd rib

on its side).

Divide the mediastinum into two parts:

1) Superior mediastinum.

2) Inferior mediastinum.

The inferior mediastinum is divided into 3 parts:

Middle mediastinum: biggest, contain the heart.

Anterior mediastinum: small, between heart and sternum, anterior to the

middle mediastinum.

Posterior mediastinum: between heart and vertebral column, big.

Pleura (sac of lungs)

When we talked about the ribs, for example the 1st rib we said that is rough superiorly and

smooth inferiorly, why?

Because it makes friction with the lungs and the delicate membrane that surround

them. This delicate membrane is called pleura.

April 10, 2012

ANATOMY LECTURE 21

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1) Development:

At the fetal time:

a) The pleura have a spherical shape.

b) The lungs start as a bud called the lung bud.

The lung bud invaginates the pleura on the medial side and start to grow on it,

building the pleura to surround the lunges with two layers (completely surround

the lungs).

Two layers:

1) Inner layer: called parietal pleura which lines the thoracic wall

2) Outer layer: called visceral pleura that completely cover the lungs (lining

the lungs).

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ANATOMY LECTURE 21

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Note:

The parietal layer is treated like the thoracic wall same innervations (intercostals),

same blood supply (arterial and venous take from intercostals artery and give to

intercostals vein).

Visceral pleura:

Considered as a layer which covers the lungs and firmly adherent.

Treated like the lungs (innervations, blood supply).

2) Parts of pleura:

Cervical pleura:

Covers the apex of the lungs (extend to the root of neck).

Anything related to the neck called cervical.

Costovertebral pleura:

Cover the costovertebral surface (convex) of lungs.

Related to the ribs and extend to the vertebrae (posteriorly).

Mediastinal pleura:

Covers the mediastinal surface. (Medial surface of lungs near the

mediastinum).

Diaphragmatic pleura:

The inferior border of the lung which is related to the diaphragm.

Diaphragm: partition between thorax and abdomen.

3) Pleural reflection

Surface anatomy: help you to draw the pleural

reflection (borders of pleura) on a patient.

April 10, 2012

ANATOMY LECTURE 21

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Right side: ( 0,2,4,6,8,10,12)

- These numbers represent ribs, each considered a point.

- If we connect these points we will get the pleura margins.

Zero: start at the apex at the root of neck (1 inch above the medial end of

clavicle) .

2, 4, 6, 8, and 10: it’s where the pleura meet the ribs.

2, 4, and 6: at the midline.

8: pleural margin meet the 8th ribs at the mid clavicular point.

10: pleura meet the 10th rib at the mid axillary line.

12: at vertebra number 12 (posteriorly).

Note:

Pleura consist of two layers outer (parietal) and inner (visceral) between these two

layers there is a space called potential space.

This space contains a fluid which lubricates the opposing surfaces of the visceral and

parietal pleura during the respiratory movement.

Left side:

- Small difference from the right side.

Zero: same.

2, 4: same.

From rib 4 to rib 6 a small deviation (to the left side) happens to the pleura at the

mid line (1 inch away from the mid line).

8, 10, and 12: same.

Clinical application:

What will happen if this pleural sac was injured?

The air will enter the sac the air will influence the lung

movement cannot expend may lead to death.

April 10, 2012

ANATOMY LECTURE 21

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Lungs

Pyramidal

Apex (upward):

Covered by cervical pleura

Reach cervical part (1 inch above the medial end of clavicle).

An injury in this area is highly dangerous (stab wounds especially)

because it contain:

1) Apex of lungs.

2) Main blood supply for head and neck.

Base (downward):

Concave.

Rest upon the convex surface of diaphragm (dome shape).

two surfaces:

1) Costovertebral surface:

Convex.

Related to the ribs and intercostals spaces.

2) Medial surface:

Contain a hilum (it’s a depression in which the roots of lungs

enter and exit).

Roots: structures that enter and exit the lungs.

The area of deviation is called the bare area of

pericardium (area of heart that is not covered with

pleura).

It’s important to differentiate between hilum and roots.

Hilum: an opening on the same tissue.

Root: structure that enter the hilum.

April 10, 2012

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Structures in the root:

1) Bronchus:

On both lungs.

Most posterior structure.

If you put your hand on it you will find it hard because it contains a

cartilage (land mark to recognize it at the exam).

Give 10 segments in each lung.

2) Pulmonary artery:

Contain non-oxygenated blood.

Blue in color.

Most superior structure.

3) Pulmonary vein:

Red in color.

We have two veins in each lungs ( total of 4 in both lungs):

a) Superior pulmonary vein (most anterior structure).

b) Inferior pulmonary vein (most inferior structure).

Note:

At the right lung before the bronchus enter it. it will divide into two bronchi.

One of the bronchi is located above the pulmonary artery (called eparterior) and the

other will be located below the pulmonary artery (called hyparterior). Named in

relation to the pulmonary artery.

On the left lung the bronchi does not divide.

4) Lymph nodes

Called hilum lymph nodes.

5) Pulmonary nerve plexus:

Autonomic (involuntary).

Supply the lung.

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6) Bronchial vessels:

Branched from the aorta.

Blood supply for the lung tissue.

The rest of the mediastinum surface contain a lot of impression

EX: cardiac impression.

Two borders:

1) Anterior border:

There is a big difference between the anterior surface of right lung and

left lung.

In the right side it is straight.

In the left side there is a notch called the cardiac notch where the

pericardium is exposed. And under it there is a process called lingual

process.

2) Posterior border:

Rounded, dome.

Question:

Does the pulmonary artery supply the lungs tissue?

NO! Because it does not contain oxygen, it just enters the lungs

to oxygenate the blood (function).

Anatomical position of lungs: (3 questions)

Which superior and inferior:

- Sup : apex

- Inf. : base

Which medial and lateral:

- Medial :mediastinal.

- Lateral: convex costovertebral.

Which anterior and posterior:

- Ant.: sharp

- Also on the anterior surface the right is straight and the left contain a

cardiac notch and lingual process.

- Post. : blond

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Each lung (left and right) contain an oblique fissure.

1) Origin: posterior opposite to the 3rd thoracic vertebra T3

2) Continue oblique until it reaches the anterior aspect (inferior border).

3) Divide the left and right lungs into two lobes (superior and inferior).

The right lung contains another fissure called horizontal fissure.

1) Start anteriorly opposite to the 4th costal cartilage disc until it meet the

oblique fissure.

Lung reflection:

Right side: (0, 4, 6, 6, 8, 10)

Zero: apex ( 1 inch above the medial end of clavicle)

2, 4: midline.

On the 6th rib there is two points:

- 1st at the midline.

- 2nd at mid clavicular.

8: mid axillary.

10: verterbral.

Left side:

0, 2, 4: the same.

After the 4th rib deviation on the left side pericardium is exposed.

2nd point on the 6 rib: the same

8, 10: same.

The right lung has 3 lobes: superior, inferior, middle.

The left lung has 2 lobes: superior, inferior.

Right lung is bigger, shorter, and broader because there is the

liver below the diaphragm on the right side.

April 10, 2012

ANATOMY LECTURE 21

11

Done By: Aseel Yaseen

Question:

1) If a patient came to the ER with a stab wound under the 10th rib, at the mid

axillary line, do u susbect an injury in the pleura?

No, we should think of the liver because under the 1oth rib there is no lung

or pleura.

2) If it was under the 9th rib?

Pleura injury air in the space non-function lung.

3) 6th rib?

Injury for both lung and pleura.