Distance of Cricopharynx During Oesophagoscopy
In adults, the cricopharynx (upper oesophageal sphincter) is located approximately 15-18 cm from the upper incisors, while in pediatric patients this distance varies with age and body size, typically ranging from 10-15 cm depending on the child's height and weight.
Adult Measurements
The distance from the upper incisors to the cricopharynx in adults can be estimated using external anatomical landmarks:
The airway length from the upper incisor to the carina (which lies distal to the cricopharynx) can be predicted using the formula: incisor-carina neutral length (cm) = 0.868 × the incisor-manubriosternal joint extension length (cm) + 4.260, with a high coefficient of determination (r² = 0.88) 1
The cricopharynx typically lies 15-18 cm from the upper incisors in adults, representing the transition point between the pharynx and cervical oesophagus 1
During endoscopy, measurements should be recorded as distance from the incisors, with the gastro-oesophageal junction serving as a key reference point distally 2
Pediatric Measurements
In children, the distance is significantly shorter and varies with growth:
The incisor-carina neutral length in children follows the formula: incisor-carina neutral length (cm) = 1.009 × the incisor-manubriosternal joint extension length (cm) + 0.468, with an even higher coefficient of determination (r² = 0.98) 1
Facial landmarks provide reliable estimates for airway dimensions in pediatric patients, with the distance from upper incisors to the angle of the mandible serving as a practical reference 3, 4
Age-based considerations show positive correlation between airway dimensions and age (r = 0.36, P < 0.001), height (r = 0.34, P < 0.001), and weight (r = 0.35, P < 0.001) 5
A weight-based formula provides better accuracy: optimal distance = 22.43 + 17.54 × log(weight[kg]), with a probability of 61.7% for proper sizing 4
Clinical Application During Oesophagoscopy
Documentation standards require recording distances from the incisors for all anatomical landmarks encountered:
The Z-line (squamocolumnar junction) position should be recorded in centimeters from the incisors 2
Barrett's islands and visible lesions should include distance measurements from the incisors 2
Resectable esophageal carcinomas are defined as those >5 cm from the cricopharyngeus, while cervical or cervicothoracic lesions <5 cm from the cricopharyngeus should receive definitive chemoradiation rather than surgery 2
Important Caveats
Anatomical variations must be considered:
The cervical esophagus lies predominantly to the left of the midline, with 50% of subjects showing the esophagus posterolateral to the cricoid ring, mainly on the left side 6
Individual patient factors including neck extension, body habitus, and anatomical anomalies can alter these measurements 2, 1
In pediatric patients, the transition from funnel-shaped to cylindrical airway anatomy occurs gradually, with the glottis (not cricoid) representing the narrowest portion throughout childhood 5