Trachea and Bronchi

Dr. Mohanad

2

Trachea (windpipe): Landmarks

Begins at lower border of Cricoid Cartilage / C6

Extends to Carina Lined by ciliated columnar epithelium Length: 9-15 cm long / 2cm in diameter 15 – 20 incomplete rings of cartilage

Bridged post. by trachealis muscle

3

Tracheobronchial Anatomy

4

Cricoid

Cricoid Cartilage

Cricothyroid membrane

Thyroid glandThyroid

cartilageCricoid cartilage

5

Trachea Variable shape

Usually round, oval, oval with flattened post. border

Square Inverted pear Horseshoe

Very pliable in children May deviate to the right at almost 90° in

normal expiratory film.

6

Trachea: Carina Ridge on internal aspect of last tracheal cartilage

Right of the midline Lies at T5 level: T4 on inspiration / T6 on

expiration Normal angle: 65° Angle increases by 10° - 15° in

recumbency (relaxing) Angle slightly larger + symmetrical in

children

7

Carina

Mucosa highly sensitive to irritants: Cough reflex

*

8

Main carina: Concepts of anterior and

posterior

9

Relations: Cervical Anterior:

Isthmus anterior to 2nd, 3rd, 4th rings

Inferior thyroid veins Strap muscles:

Sternohyoid, Sternothyroid

Posterior: Oesophagus, recurrent

laryngeal nerves Lateral:

Lobes of thyroid Common carotid artery

10

Relations: Thoracic

Anterior: Brachiocephalic a. Left common carotid a. Left brachiocephalic v.

11

Relations: Thoracic

Posterior: Oesophagus Left recurrent

laryngeal n.

12

Blood supply

Upper trachea Inferior thyroid

artery Lower part

Branches of the bronchial artery

Venous drainage Inferior thyroid

venous plexus

Trachea Lined with respiratory

epithelium (ciliated pseudo-stratified columnar epithelium.)

“C”-shaped pieces of hyaline cartilage protecting airway while allowing for swallowing

Trachealis muscle (smooth muscle) runs across posterior wall of trachea connecting ends of tracheal cartilage

Trachea

Low power

Medium power High power

PseudostratifiedCiliated columnar

epithelium

Loose connec

tive tissue

Hyaline cartilage Connective tissue

TRACHEA

Bronchus

Two principal bronchi begin at bifurcation of trachea

Each bronchi subdivides into successive generations of smaller bronchi and reach the lung

Each bronchus consists of extra-pulmonary and intra-pulmonary part

Right Bronchus It is wider ,shorter and more

vertical

Wider because supplies more voluminous air, vertical because trachea bifurcation deviates more to right side

Foreign body in the trachea is usually aspirated more to the right side

It enters the root of the right lung and reaches the Hilum at the level of 5th thoracic vertebrae

Left Bronchus

Longer, narrower and more oblique than right bronchus

Extra-pulmonary part 5 cm in length It enters the lung at the hilum at the level of 6th thoracic

vertebrae.

Intrapulmonary part The left principal bronchus divides into upper and lower

bronchi to supply the respective lobe of left lung. It divides into ascending and descending branches which

supply the bronchopulmonary segments.

Pulmonary bronchi

Within the lung, the principal bronchus divides into secondary or lobar bronchi

Each secondary bronchus divides Into Segmental or Tertiary Bronchi.

The area of the lung aerated by a tertiary bronchus is known as Bronchopulmonary segment.

Intrapulmonary bronchus

Ciliated cells Basal cells

Goblet cells

Brush cells

Small granule cells Clara cells

Cells types found in Luminal Epithelium of Bronchioles

BRONCHIOLE