The Impact of Supratrochlear Foramen on Humeri’s Medullary Canal Diameter and Its Surgical Implications

Introduction Supracondylar elbow fractures are prevalent in the pediatric age group, and retrograde intramedullary nailing of the humerus is a common treatment approach. The anatomy of the medullary canal and the presence of the supratrochlear foramen (STF) significantly influence the stabilization of the nail. This study aimed to determine the incidence and morphology of the STF and compare the width of the medullary canal in humeri with and without the STF. Methods We examined 40 humeri bones with fused humeral epiphyses for the presence of the STF obtained from the Department of Anatomy's osteology collections. We studied the morphology and measured the dimensions of the foramen. We then compared the morphometric characteristics of humeri bearing the STF with those without it. We also took radiographs of all bones and measured the medullary canal width at three levels. We compared the measured width of the medullary canal in humeri between those with an STF and those without. This analysis was performed using IBM SPSS Statistics version 27.0 (Armonk, NY: IBM Corp.) for Windows and an unpaired t-test. We considered p-values of less than 0.05 as statistically significant. Results We found the STF in six bones (15%) as follows: four on the left side and two on the right. Humeri with the STF had smaller mean head circumference, length, and shaft circumference than those without the foramen. However, this difference was not statistically significant (p>0.05). The mean width of the medullary canal in humeri with the STF was significantly smaller (p<0.05) than in bones without the STF. Conclusions Our study revealed that humeri with an STF present a significantly smaller diameter of the medullary canal, which can impact surgical procedures like retrograde intramedullary nailing. Clinicians should consider this when planning surgeries to avoid iatrogenic fractures and enhance procedural efficiency. Our data also suggest that larger humeri are less likely to have an STF, potentially influencing pre-surgical planning and fracture risk assessment.