Abstract

Background: Foramen magnum (FM) is the most prominent opening in the floor of the posterior cranial fossa. Occipital condyle (OC) protrusion into the FM alters the measurements and produces an impact on the surgical access. Diagnostic modalities such as computed tomography (CT) and magnetic resonance imaging scan made revolutionary changes in assessing the skull base.

Aims and Objectives: The aim of our study is to measure the morphometric measurements of FM, OC and assess the shapes of the FM.

Materials and Methods: An observational descriptive study on morphometric measurements of FM and OC is conducted in dry skulls and CT scan images. Area, index, and shapes of FM were calculated and tabulated. Relationship between the FM dimensions was statistically analyzed using student t-test (P < 0.05).

Results: There was no significant difference of means (P > 0.05) between the FM and OC parameters with respect to dry skulls and CT measurements. The study results showed that CT is good in predicting the measurements of FM. Our results on shapes of FM showed highest occurrence of the hexagonal (28.57%) followed by diamond shape (22.8%) in dry skulls and CT images. On applying the kappa statistics, there was no agreement in shapes of FM between dry skulls and CT images.

Conclusion: Our study hopes to provide extensive knowledge of FM and OC for the operative surgeons and aids in the reduction of iatrogenic complications.

Key words: Foramen Magnum; Occipital Condyles; Dry Skulls; Hexagonal Shape Transcondylar Approach