Carina of trachea

The carina of trachea (also: "tracheal carina"^[1]) is a ridge^[1] of cartilage^[2] at the base of the trachea separating the openings of the left and right main bronchi.^[1][2]

Carina of trachea
Cartilages of larynx, trachea and bronchi. (Carina is at the point of bifurcation.)
Transverse section of the trachea, just above its bifurcation, with a bird’s-eye view of the interior. (Carina not labeled; the ridge that separates the left and right bronchus.)
Details
System	Respiratory system
Identifiers
Latin	carina tracheae
TA98	A06.3.01.009
TA2	3225
FMA	7465
Anatomical terminology [edit on Wikidata]

Structure

The carina is a cartilaginous ridge separating the left and right main bronchi that is formed by the inferior-ward and posterior-ward prolongation of the inferior-most tracheal cartilage.^[2]

The carina occurs at the lower end of the trachea - usually at the level of the 4th to 5th thoracic vertebra.^[3][4] This is in line with the sternal angle, but the carina may raise or descend up to two vertebrae higher or lower with breathing. The carina lies to the left of the midline, and runs antero-posteriorly (front to back).^{[citation needed]}

Blood supply

The bronchial arteries supply the carina and the rest of the lower trachea.^[5]

Relations

The carina is around the area posterior to where the aortic arch crosses to the left of the trachea.^[4] The azygos vein crosses right to the trachea above the carina.^[6]

Physiology

The mucous membrane of the carina is the most sensitive area of the trachea and larynx for triggering a cough reflex.^{[citation needed]}

Clinical significance

Tracheobronchial injury, an injury to the airways, occurs within 2.5 cm of the carina 60% of the time.^[7]

Diagnostic radiology

Widening and distortion of the carina is a serious radiological sign that usually indicates carcinoma of the lymph nodes around the region where the trachea divides.^{[citation needed]}

Additional images

• 
  Anatomical dissection of trachea and main bronchi showing the carina
• 
  Anatomy of the trachea