Lungs

Anatomy I (MSAT 213)For PT & RCLecture (9)

Prepared by:

Dr. Kamal Motawei

Lungs

The lung is a soft and

spongy organ

It is very elastic; so if the

pleural cavity is opened, it shrinks

to 1/3 in volume.

The rt. lung is larger, broader & The rt. lung is larger, broader &

shorter than the left lung.

Color: pink (in children) to

dark and mottled (in adults)

Position: the lungs lie on

either side of the mediastinum,

surrounded by the pleura

Lungs

Shape: each lung is

conical in shape, having:

�Apex

�Base

�2 surfaces:

�Mediastinal

surface

�Costal surface

�3 borders:

�Anterior border

�Posterior border

� Inferior border

Lungs: shape

Apex of the lung: It is blunt

It projects in the neck; about

one inch above the clavicle

It is covered with the

cervical pleura and the

suprapleural membrane.suprapleural membrane.

Base of the lung:It is concave and rests on the

corresponding dome of the

diaphragm.

Borders of the lungs:

Anterior border of the lung:

– It is Sharpe

– It lies in the costomediastinal

recess of the pleura.

– In the left lung: it shows

cardiac notch and lingula.

Posterior border of the lung:Posterior border of the lung:

– It is blunt and huge (it may be

called posterior surface)

– It occupies the paravertebral

gutter.

Inferior border of the lung:

– Sharpe and occupies the

costodiaphragmatic recess

during inspiration.

Surfaces of the lungs:

1) Costal surface of the lung:

– It is convex

– It faces the costal wall (ribs, costal cartilages & intercostal spaces).

Surfaces of the lungs:

2) Mediastinal surface of the lung:

– It is concave

– It is molded to the mediastinal structures.

– At its middle, it shows the hilum of the lung through which the main

bronchus and neurovascular bundle pass to the lung representing the

root of the lung.

Lung: Hilum

Hilum of the lung:It is the site where structures pass

to and from the lung.

It is situated on the middle of the

mediastinal surface of the lungmediastinal surface of the lung

The hilum is the site where the

parietal pleura is reflected on the

root of the lung as a cuff to be

continuous with the visceral pleura.

This cuff of pleura is redundant

inferiorly, in the form of double

layers of pleura called pulmonary

ligament.

Lung: Root

Root of the lung:It is the structures connecting the

lung to the mediastinum.

Contents of the root of lung:

– Main bronchus (usually the

right one divides before

entering the rt. lung)

– Bronchial vessels

– Pulmonary artery

– 2 Pulmonary veins

– Pulmonary nerve plexuses

– Bronchopulmonary lymph

nodes and lymphatics

Fissures of the Lungs:

Oblique fissure: it runs from

the inferior border upward and backward

across the medial and costal surfaces until it

cuts the posterior border 2 ½ inches below

the apex.

The horizontal fissure: The horizontal fissure: It follows the fourth intercostal space from

the sternum until it meets the oblique fissure

as it crosses rib V.

It is present in the rt. lung only.

Lobes of the lungs:The right lung is

divided by the

oblique and

transverse fissures

into:

– Upper lobe

– Middle lobe

– Lower lobe– Lower lobe

The left lung is

divided by the

oblique fissure

into:

– Upper lobe

– Lower lobe

Each lobe has a secondary

bronchus.

A bronchopulmonary segment is

a functionally and structurally

independent unit .

It is pyramidal in shape with the

apex towards the root of the lung

and base towards the lung

Bronchopulmonary segments of the lungs:

and base towards the lung

surface.

Each bronchopulmonary segment

has: tertiary (segmental)

bronchus, branch of the pul. art,

pul. veins, lymphatics and

autonomic nerves.

Each bronchopulmonary segment

is surrounded by connective

tissue.

Bronchopulmonary segments of the lungs:

Bronchopulmonary segment of

the right lung:

– Superior lobe:

1) Apical, 2) posterior, 3) anterior

– Middle lobe:

4) lateral, 5) medial

– Inferior lobe: – Inferior lobe:

6) superior, 7) medial basal, 8) anterior basal

9) lateral basal, 10) posterior basal

Bronchopulmonary segment of

the left lung:

– Superior lobe:

1) Apical, 2) posterior, 3) anterior

4) Superior lingular, 5) inferior lingular

– Inferior lobe:

6) superior, 7) medial basal, 8) anterior basal

9) lateral basal, 10) posterior basal

Blood supply of the Lungs:Bronchial arteries:

They are branches of the descending aorta.

They supply:

1)The bronchial tree, 2) the connective tissue

stroma , 3) visceral pleura

Bronchial veins:

They drain into the azygos and

hemiazygos veins

Pulmonary arteries:Pulmonary arteries:

Each lung receives one pulmonary artery.

Its terminal branches supply the aveoli

with deoxygenated blood

Pulmonary veins:

After oxygenation of the blood in the

alveolar capillaries, oxygenated blood

leaves the lungs via two pulmonary

veins.

The tributaries of the pulmonary veins

pass through the intersegmental septa.

Lymph drainage of the lungs

Deep lymph plexus (around the

bronchi & pul. vessels) drains into

the pulmonary L.N. close to the

hilum, then to the

bronchopulmonary L.N. in the

hilum, then bronchomediastinal

lymph trunk, then right lymph lymph trunk, then right lymph

trunk or thoracic duct.

Superficial lymph plexus (under the visceral pleura) drains

into the bronchopulmonary L.N.

Nerve supply of the lungs

Pulmonary plexus: in

the root of the lung

receives branches

from the sympathetic from the sympathetic

trunk and the vagus

nerve.

Pleura & lungSurface marking

Lungs: surface anatomy