MORPHOLOGY OF THE HYPOGLOSSAL CANAL IN ADULT KENYANS
Background: In the modern era, technological advancements have made it easier to access the craniovertebral junction lesions using microsurgical techniques. The rate of post-surgical complications is however, still high owing to population specific variations. Data on the morphology of the hypoglossal canal and especially the relation to the underlying occipital condyle may aid in reducing such complications. Materials and methods: Descriptive cross-sectional analysis of one hundred and eight (108) skulls obtained from the National Museums of Kenya (Male = 76, Female = 32). The location of the hypoglossal canal was determined in relation to the occipital condyle. The canal bridging pattern was documented. The distance between the HC and the carotid canal and jugular foramen was measured using a digital Vernier calipers (precision 0.01 mm). Measurements were also made of the intracranial and extracranial canal diameters. Data were entered into SPSS (Version 25.0, Chicago, Illinois) for analysis. A p-value <0.05 was considered significant at 95% confidence interval. Results: The IOHC was located predominantly in the middle third of the occipital condyle (84.7%, 183/216 sides). Clinically significant sex and side differences were observed with males and the left side having a higher prevalence in the posterior third. Presence of a bridge was noted in 15(13.8%) skulls. The prevalence of bridging was significantly more in males (P value = 0.033). The average diameter of the intracranial and extracranial orifices of the hypoglossal canal were 6.39 ± 1.51mm and 6.58 ± 1.44mm respectively. The mean distance from the hypoglossal canal to the jugular foramen and carotid canal were 10.32 ± 4.54mm and 12.89 ± 1.55mm respectively. Conclusion:The existence of the intracranial orifice of the hypoglossal canal in the posterior third of the occipital condyle and the high prevalence of bridging should be important considerations during preoperative preparation, particularly in males, in craniovertebral surgeries in Kenyans. Data on the diameter of the hypoglossal canal orifices may further help anthropologists better understand the variations between populations.