Tracheostomy

Describe the anatomy relevant to the performance of a naso, or endo, tracheal intubation, a cricothyroidotomy or tracheostomy

Trachea

The trachea is fibrocartilagenous tube which:

• Extends from the larynx superiorly to the Plane of Louis inferiorly
• Terminates by division into the right and left mainstem bronchi
• Runs at 15 degrees parallel to the surface of the neck, such that the distal trachea is deeper than the proximal trachea
• Has a D-shaped cross section
  • Anterior wall is formed by 18-22 incomplete cartilaginous rings which maintain tracheal patency
  • Posterior wall of the trachea is spanned by longitudinal smooth muscle known as trachealis
• Is typically:
  • 10cm long
  • 2.3cm wide
  • 1.8cm in AP diameter

Relationships

• Lateral to the trachea are the:
  • Carotid sheaths
    Contains the carotid artery, internal jugular vein, and vagal nerves.
  • Thyroid lobes (and inferior thyroid arteries)
  • Recurrent laryngeal nerves.
• Inferior to the thyroid isthmus lies the thyroid veins
• Posterior to the trachea are the:
  • Oesophagus
  • Vertebral column

Surface Anatomy

Midline neck structures are relevant surface anatomy:

• Laryngeal structures
  Including: Hyoid, thyroid cartilage, cricothyroid membrane, cricoid cartilage.
• Sternal notch
• Thyroid lobes
  Lie lateral to trachea.

Layers of Dissection

• Skin
• Subcutaneous fat
• Superficial and Deep Pretracheal fascia
• Tracheal wall
  • Ideally between 1st and 2nd rings

References

1. McMinn, RMH. Last's Anatomy: Regional and Applied. 9th Ed. Elsevier. 2003.