Anatomy: Trachea Chris van Zyl KHC

Trachea: Landmarks Begins at lower border of cricoid cartilage / C6 2 Begins at lower border of cricoid cartilage / C6 Extends to Carina Right of the midline Sternal angle T4 on inspiration / T6 on expiration Lined by ciliated columnar epithelium 15 cm long / 2cm in diameter 15 – 20 incomplete rings of cartilage Bridged post. by trachealis muscle

Trachea 3

Trachea Variable shape Very pliable in children 4 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.

Trachea: Carina Lies at T5 level Normal angle: 65° T4 on expiration T6 on inspiration Normal angle: 65° 20° to right of midline 40° to left of midline Angle slightly larger + symmetrical in children Angle increases by 10° - 15° in recumbency

Relations: Cervical Anterior: Posterior: Lateral: 6 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

Relations: Thoracic Anterior: Brachiocephalic a. 7 Anterior: Brachiocephalic a. Left common carotid a. Left brachiocephalic v.

Relations: Thoracic Posterior: Oesophagus Left recurrent laryngeal n. 8 Posterior: Oesophagus Left recurrent laryngeal n.

Relations: Thoracic Left lateral: Right lateral: Arch of the aorta 9 Left lateral: Arch of the aorta Left common carotid Left subclavian arteries Right lateral: Right vagus nerve Arch of the azygos vein Pleura

Blood supply Upper trachea Lower part Venous drainage 10 Upper trachea Inferior thyroid artery Lower part Branches of the bronchial artery Venous drainage Inferior thyroid venous plexus

Right Paratracheal Stripe 11 Interface between trachea and right upper lobe Max normal thickness 4 mm

Left Paratracheal Stripe 12 Left upper lobe and trachea Less common (only on 21 %- 31% of films

Posterior Tracheal Stripe 13 Interface between trachea and right lung Normal max diameter 2.5 mm

Tracheoesophageal Stripe 14 Interface between esophagus and trachea Normal max diameter 5.5 mm

References Lines and Stripes: Where Did They Go? 15 Lines and Stripes: Where Did They Go? Jerry M. Gibbs, Chitra A. Chandrasekhar, Emma C. Furgasson, Sandra A. A. Oldham Applied Radiological Anatomy Paul Butler, Adam W. M. Mitchell, Harold Ellis Anatomy for Diagnostic Imaging Stephanie Ryan, Michelle McNicholas, Stephen Eustace Third Edition