Abstract
Background and objectiveThe morphology and morphometry of the foramen magnum (FM), which provides a passageway to vital neurological structures that relay information to and from the brain and spinal cord, are significant for many surgical approaches and applications. It was aimed to investigate the morphometric and morphological features of the FM on the cone-beam computed tomography (CBCT) images and to review the literature in detail.MethodsCBCT images of 400 individuals (200 males, 200 females, aged between 18 and 65) were evaluated by Planmeca Romexis Viewer. The length, width, perimeter, and area of the FM were examined and samples were classified according to shape. Also, the FM index (FMI) was calculated.ResultsThe mean values of the length, width, and perimeter were found to be 36.75±2.50 mm, 32.55±2.93 mm, and 108.35±7.50 mm, respectively. The area of FM was found to be 941.81±128.26 mm2, 946.83±127.39 mm2, and 895.76±123.50 mm2 with Planmeca Romexis Viewer, Radinsky formula, and Teixeira formula, respectively. All parameters were significantly larger in males than females. There was no correlation between age and these parameters. Also, seven shapes were determined for FM, and the most common shape was oval. FM index was evaluated according to the Martin and Saller classification. It was found that 16.5% of the cases belonged to the narrow, 16% belonged to the medium, and 67.5% to the large FM index. There was no correlation between age and FM index.ConclusionMorphometric and morphological features of the FM located in the craniovertebral junction (CVJ), which is a highly complex area, are variable. Surgical procedures and approaches in this region are essential due to the high mortality rate. For this reason, anatomical structures in these regions should be well known before surgery. The quantitative data presented in this study, which made a detailed literature comparison, may assist in surgical procedures around the FM and the planning of these procedures.
Highlights
The foramen magnum (FM) is the most remarkable structure located in the occipital bone of the skull
FM index was evaluated according to the Martin and Saller classification
It was found that 16.5% of the cases belonged to the narrow, 16% belonged to the medium, and 67.5% to the large FM index
Summary
The foramen magnum (FM) is the most remarkable structure located in the occipital bone of the skull. Vital neurological structures which relay information to and from the brain and spinal cord pass via FM. It lies in an anteromedial position and leads into the posterior cranial fossa [1]. Zdilla et al [3] stated that the studies of the FM shape had been performed with ambiguous and subjective terminology that varies between previous studies. Chethan et al [4] stated that the existence of some correlation between the shape of the FM and ancestry of an individual has been reported. The morphology and morphometry of the foramen magnum (FM), which provides a passageway to vital neurological structures that relay information to and from the brain and spinal cord, are significant for many surgical approaches and applications. It was aimed to investigate the morphometric and morphological features of the FM on the cone-beam computed tomography (CBCT) images and to review the literature in detail
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