Download Trachea and bronchial tree

Definition: It is a fibromuscular tube 10 cm long
containing incomplete
cartilaginous rings.
Beginning: At the lower
border of the cricoid cartilage
(at the level of C 6).
Course:
- It begins in the midline and
terminates slightly to the right
of the midline.
- It lies in the superior
mediastinum.
Termination:
- At the level of T 4 (sternal
angle).
- Anterior: Innominate
artery, left innominate
vein and thymus gland.
- Posterior: Oesophagus
and left recurrent
laryngeal nerve.
- Right: Right vagus,
arch of azygos, right lung
and pleura.
- Left: Arch of the
aorta,left common
carotid and subclavian
arteries, left vagus and
phrenic nerves.
Blood supply:
a. Inferior thyroid arteries.
b. Bronchial arteries from the descending thoracic
aorta (left side).
c. Right superior intercostal artery (right side).
- It is drained by the inferior thyroid veins.
Nerve supply:
- Sympathetic ---- Sympathetic trunk.
- Parasympathetic ---Vagi nerves.
The trachea terminates at the level of T 4 by dividing into
right and left main bronchi which are asymmetrical.
- When a foreign body enters the trachea it passes through
the right main bronchus.
Right Main Bronchus
Left Main Bronchus
- Shorter (1 inch).
- Longer (2inches).
- Wider.
- Narrower.
- More in line with the trachea.
- More horizontal.
- Divides before its entry into the lung.
- Divides inside the lungs.
- The trachea divides into right
and left main bronchi. With more
division of the main bronchi they
give rise to lobar then segmental
bronchi.
Each segmental bronchus is
distributed to a localized part of
lung tissue forming what is called
the broncho-pulmonary segments.
The right bronchus divides into: 1superior lobar bronchus and 2middle and inferior lobar
bronchus.
The left bronchus divides into
superior and inferior lobar bronchi.
Each lobar bronchus is divided
into segmental bronchi.
Right bronchus
Superior lobar
bronchus
1. Apical
3. Posterior
2. Anterior
Middle lobar bronchus
4. Medial
Inferior lobar bronchus
6. Apical basal 7. Medial basal
8. Lateral basal 9. Anterior basal
10. Posterior basal
5. Lateral
Left bronchus
1.
Apicoposterior
3. Sup. lingular
2. Anterior
4. Inf. lingular
----------------------------------------------------
5. Apical basal
6. Lateral basal
7. Anteromedial basal 8. Posterior basal
Origin:
*Endoderm of foregut endothelium& glands.
*Splanchnic mesoderm Ms, CT, tracheal rings.
Development:
* Ventral border of oesophagus laryngotracheal
diverticulum ( opened cranially& blind caudally)
Elongates, separates from the oesophagus trachea.
Development:
*The blind caudal
end of the trachea
dilates gives
lung bud
divides into right
and left buds.
*Right lung bud
three branches:
1-Upper lat.
branch upper
lobe bronchus .
2-Stem lower
lobe bronchus.
3-Lower lat.
Branchmiddle
lobe bronchus.
1-Upper lobe bronchus
three branches (3ry):
a. Apical b. Anterior
c. Posterior
2-Lower lobe bronchus
five branches (3ry):
a. Apical basal
b. Anterior basal
c.Posterior basal
d. Medial basal
e. Lateral basal
3- Middle lobe bronchus
two branches (3ry):
a.Medial
b. Lateral
*Left lung bud (1ry
) two
branches:
1-One lat.
Branch(2ry)
upper lobe
bronchus.
2-Stem lower
lobe bronchus.
1-Upper lobe bronchus
two branches (3ry):
A-Upper:
a. Apicoposterior
b. Anterior
B- Lower ( lingular):
a. Superior b. Inferior
2-Lower lobe bronchus
four branches (3ry):
a. Apical basal
b. Anteromedial basal
c.Posterior basal
d. Lateral basal
•
•
•
Each tertiary
bronchiole divides
repeatedly 18
generations.
The final generation
dilates alveoli.
After birth extra 6
generations until the
age of 8 years 18+
6= 24 generations.
1- Tracheo-oesophageal fistula:
No separation between the trachea and oesophagus
*milk pass to the lungpneumonia.
*air pass to stomach dilatation resp. impairment.
2- Variation in the number of lobes of the lung.
3- Congenital cysts of a lung:
Due to dilatation of terminal bronchioles.
4- Congenital atelectasis of a lung or lobe:
due to obstruction of 1ry or 2ry bronchioles.
5- Respiratory distress syndrom:
Due to deficiency of surfactants secreted from type II
pneumocytesno dilatation of alveoli death.
Prof.: Dr. Wafaa Abdel-Rahman