Anatomic relation between the external branch of the superior laryngeal nerve and the thyroid gland

This prospective study investigated the anatomic relations between the external branch of the superior laryngeal nerve (EBSLN), the superior thyroid artery (STA) and the thyroid gland in human cadavers.

Twenty-two human cadavers aged over 18 years old, less than 24 hours after death.

The mean distance between the EBSLN and the superior pole of the thyroid gland was 7.68 ±3.07 mm. A tangent to the inferior edge of the thyroid cartilage between the EBSLN and the STA measured 4.24 ±2.67 mm. A line from the intersection of the EBSLN - related to the STA - to the superior pole of the thyroid gland measured 9.53 ±4.65 mm. A line from the EBSLN to the midline of the most caudal point of the thyroid cartilage measured 19.70 ±2.82 mm. A line from the RENLS to the midline on the most cranial point of the cricoid cartilage was 18.35 ±3.66 mm.

There is a variable proximity relation between the EBSLN and the superior pole of the thyroid gland; this distance ranges from 3.25 to 15.75 mm. There was no evidence of significant variation between the measures in the ethnic groups comprising the sample.