Yurasakpong Laphatrada, Suwannakhan Athikhun, Asuvapongpatana Somluk, Tubbs R Shane, Iwanaga Joe, Iamsaard Sitthichai, Samrid Rarinthorn, Berkban Thewarid, Chaiyamoon Arada
Department of Anatomy, Faculty of Science, Mahidol University, Bangkok, Thailand.
Department of Biomedical Sciences, College of Medicine and Health, University of Birmingham, Birmingham, UK.
Surg Radiol Anat. 2025 Sep 24;47(1):214. doi: 10.1007/s00276-025-03732-7.
Anatomical variations of the clivus may have clinical and embryological relevance but remain underexplored in specific populations. This study investigated the prevalence and morphometric characteristics of clival anatomical variants in dried human skulls from the Northeastern Thai population.
Three hundred four dried human skulls (282 males, 22 females) were examined macroscopically. Variations of the clivus were identified and recorded by two independent observers, with discrepancies resolved by consensus. Descriptive statistics were used to report prevalence. Morphometric measurements (height and breadth) were taken for applicable variants using a digital caliper. Chi-square tests assessed sex differences.
Fossa navicularis magna and tubercle at the anterior margin of the foramen magnum were the most prevalent variants, each observed in 38 skulls (12.5%). The basilar processes were found in 12 skulls (3.9%), condylus tertius in 5 skulls (1.6%), and prebasioccipital arch in 1 skull (0.3%). These variations showed variable morphometry. Fossa navicularis magna averaged 5.1 mm in height and 4.1 mm in breadth; tubercle at the anterior margin of the foramen magnum, 2.7 mm in breadth; basilar processes, 3.9 mm in height; condylus tertius, 6.3 mm in height and 6.9 mm in breadth; and prebasioccipital arch, 10.5 mm in height and 15.5 mm in breadth. No significant sex differences were found for fossa navicularis magna (p = 0.40), tubercle at the anterior margin of foramen magnum (p = 0.61) or basilar process (p = 0.67).
Clival variants, especially fossa navicularis magna and anterior tubercles, were found in 12.5% of skulls in this first study on Northeastern Thais. These may impact imaging interpretation and skull base surgery, reiterating the need for anatomical awareness in clinical contexts.
斜坡的解剖变异可能具有临床和胚胎学意义，但在特定人群中仍未得到充分研究。本研究调查了泰国东北部人群干燥人头骨中斜坡解剖变异的发生率和形态学特征。
对304个干燥人头骨（282例男性，22例女性）进行宏观检查。由两名独立观察者识别并记录斜坡的变异情况，如有分歧则通过协商解决。采用描述性统计报告发生率。对适用的变异采用数字卡尺进行形态学测量（高度和宽度）。采用卡方检验评估性别差异。
大舟状窝和枕骨大孔前缘结节是最常见的变异，各在38个颅骨中观察到（12.5%）。在12个颅骨中发现基底突（3.9%），5个颅骨中发现第三髁（1.6%），1个颅骨中发现枕骨前弓（0.3%）。这些变异表现出不同的形态学特征。大舟状窝平均高度为5.1毫米，宽度为4.1毫米；枕骨大孔前缘结节宽度为2.7毫米；基底突高度为3.9毫米；第三髁高度为6.3毫米，宽度为6.9毫米；枕骨前弓高度为10.5毫米，宽度为15.5毫米。大舟状窝（p = 0.40）、枕骨大孔前缘结节（p = 0.61）或基底突（p = 0.67）未发现显著性别差异。
在这项针对泰国东北部人的首次研究中，12.5%的颅骨存在斜坡变异，尤其是大舟状窝和前结节。这些可能会影响影像学解读和颅底手术，再次强调了临床环境中解剖学知识的必要性。
