Trachea

Question 1

Trachea position in neck

Answer 1

▪️starts at cricoid cartilage at the level of C6
▪️anterior to oesophagus
▪️lies within a visceral compartment surrounded by pre-tracheal layer of fascia
▪️11cm long and 2.5cm diameter

Question 2

Trachea position in thoracic cavity

Answer 2

▪️enters superior thoracic aperture
▪️lies in an oblique plane-tilted anterosuperiorly
▪️bifurcates at T4/5 (carina) same position as the sternal angle which is palatable

Question 3

Structure of trachea

Answer 3

▪️fibroelastic tube kept open by c-shaped cartilage rings

▪️posterior side covered by trachealis muscle which is elastic and allows oesophagus space when swallowing

Question 4

Histology of trachea

Answer 4

▪️4 layers

• mucosa -goblet cells (pseudostratified ciliated columnar epithelium)-prevents trachea from drying out and collapsing
• submucosa-connective tissue
• fibrocartilage- 16/20 rings
• adventitia- binds trachea to adjacent structure in the neck and mediastinum

Question 5

Bronchi structure

Answer 5

▪️trachea divides at carina into left and right bronchi
▪️right main bronchus is wider and shorter and more vertical (2.5cm)-more likely for object to get stuck
▪️left main bronchus is narrower and longer and more horizontal (5cm)

Question 6

Bronchi tree

Answer 6

▪️R/L main bronchus 
▪️secondary/ lobar bronchus 
▪️tertiary/segmental bronchus 
▪️terminal bronchus 
▪️bronchioles 
▪️2-11 alveolar ducts 
▪️alveolar sacs