Tracheoesophageal Groove Anatomy
Definition and Location
The tracheoesophageal groove (TEG) is the anatomical space formed between the posterolateral aspect of the trachea and the anterior surface of the esophagus, serving as a critical landmark for identifying the recurrent laryngeal nerve during neck surgery. 1
Anatomical Boundaries and Contents
The TEG is bounded anteriorly by the tracheal cartilages and posteriorly by the esophagus, creating a longitudinal depression on each side of the trachea 2
The recurrent laryngeal nerve (RLN) courses through this groove in approximately 63.7% of cases, though this location shows considerable anatomical variation 2
The right RLN follows a more superficial course along the lateral esophageal edge, while the left RLN loops around the aortic arch and ascends in the TEG in a deeper position 1, 3
Laterality and Symmetry
Contrary to traditional surgical teaching, recent cadaveric studies demonstrate no significant anatomical differences between the right and left tracheoesophageal grooves. 4
Measurements at tracheal rings 2,4, and 6 show no significant difference in RLN depth, lateral distance from the posterior tracheal margin, or distance to the anterior midline between right and left sides 4
The left RLN is only approximately 1 mm deeper than the right at the second tracheal ring, which is not clinically significant 4
This finding challenges the common belief that a left-sided cervical approach to esophageal mobilization is inherently safer 4
Relationship to the Esophagus
In 50% of individuals, the esophagus sits posterolateral to the cricoid ring (mainly on the left side) rather than directly posterior as traditionally assumed 5
The hypopharynx, not the esophagus, lies directly behind the cricoid ring at the level of the tracheoesophageal junction 5
The esophagus may be displaced laterally with external pressure, increasing lateral displacement from 53% to 91% in some studies 5
Clinical Significance for Surgery
The TEG is less reliable as an anatomical landmark compared to the Ligament of Berry, with the RLN located inside the TEG in only 63.7% of cases versus superficial to Berry's ligament in 78.2% of cases. 2
Key Surgical Considerations:
Both the TEG and Berry's ligament should be used together to prevent iatrogenic RLN injuries during thyroidectomy 2
Blind ligatures or coagulation must be avoided in the area of the tracheoesophageal groove 5
The short tract (<2 cm) of RLN near Berry's ligament represents the most dangerous anatomical area where most lesions occur 5
Complete visualization and nerve dissection from thoracic inlet to larynx is considered the gold standard approach 5
Anatomical Variations
Non-recurrent laryngeal nerve is a rare variant (0.3-1.6% incidence) that does not follow the typical TEG course and is more common on the right side 1
The relationship between the RLN and inferior thyroid artery within the TEG is highly variable 1
Precocious division of extralaryngeal branches may occur within the groove, requiring careful dissection 5
Common Pitfalls
Assuming the esophagus is always directly posterior to the trachea can lead to inadequate visualization of laterally positioned structures 5
Relying solely on the TEG as a landmark without considering Berry's ligament increases risk of nerve injury 2
Applying continuous traction during dissection in the TEG is a main cause of RLN injury and should be avoided in favor of intermittent tension 5
Assuming the right side is inherently more dangerous than the left is not supported by anatomical evidence 4