Vinutha S P, Suresh V, Shubha R
Assistant Professor, Department of Anatomy, JSS Medical College, Mysore, Karnataka, India.
Associate Professor, Department of Radiodiagnosis, Kempegowda Institute of Medical Sciences, Bangalore, Karnataka, India.
Anat Res Int. 2018 Sep 26;2018:2056291. doi: 10.1155/2018/2056291. eCollection 2018.
The foramen magnum as a transition area between skull and spine plays an important role as a landmark, because of its close relationship to vital structures such as the brain and spinal cord. Configuration and size of the foramen magnum play an important role for assessing craniovertebral relations. The objectives of the present study are to find out shape and dimensions of foramen magnum in cranial CT scans. All the variables were evaluated by using discriminant function analysis.
The study sample comprised 200 CT scans (110 males and 90 females) of south Indian origin. The shapes of the foramen magnum were classified into 8 types: oval, egg, round, tetragonal, pentagonal, hexagonal, irregular (A), and irregular (B). The parameters were noted meticulously and the statistical analysis for sex comparison was made by Student's -test and was considered significant whenever ≤0.05. To determine the relationships between the studied parameters, Pearson correlation coefficients were calculated.
The foramen magnum was classified into 8 types based on shape. Commonest was oval and pentagonal was the least common type. The anteroposterior diameter, transverse diameter, circumference, and area were significantly greater in males than in females (<0.001). The mean FM index of male CT scans was 85.01 ± 8.67, whereas in case of female CT scans, it was 83.17 ± 7.78. With all the variables in consideration, overall 65% of cranial CT scans were sexed correctly by using multivariate analysis.
Several anatomic parameters such as shape and dimensions of FM should be taken into consideration during surgery involving the craniovertebral junction. Also these can be used during forensic and anthropological investigation of unknown individuals for determining gender, ethnicity, and so on. The multivariate analysis is by far the best method for determination of sex of cranium with available resources.
枕骨大孔作为颅骨与脊柱之间的过渡区域，由于其与脑和脊髓等重要结构关系密切，作为一个地标起着重要作用。枕骨大孔的形态和大小在评估颅颈关系中发挥着重要作用。本研究的目的是在头颅CT扫描中找出枕骨大孔的形状和尺寸。所有变量均通过判别函数分析进行评估。
研究样本包括200例来自南印度的CT扫描（110例男性和90例女性）。枕骨大孔的形状分为8种类型：椭圆形、卵形、圆形、四边形、五边形、六边形、不规则形（A）和不规则形（B）。仔细记录各项参数，并通过学生t检验进行性别比较的统计分析，当p≤0.05时被认为具有显著性。为确定所研究参数之间的关系，计算了Pearson相关系数。
枕骨大孔根据形状分为8种类型。最常见的是椭圆形，最不常见的是五边形。男性的前后径、横径、周长和面积均显著大于女性（p<0.001）。男性CT扫描的平均枕骨大孔指数为85.01±8.67，而女性CT扫描的平均枕骨大孔指数为83.17±7.78。综合所有变量，使用多变量分析总体上65%的头颅CT扫描能够正确判断性别。
在涉及颅颈交界区的手术中，应考虑枕骨大孔的形状和尺寸等多个解剖参数。这些参数也可用于对不明身份个体的法医和人类学调查，以确定性别、种族等。就现有资源而言，多变量分析是确定颅骨性别的最佳方法。
