Abstract:
The foramen magnum (FM) is an important anatomical region of the skull base and is of significance for anatomy, anthropology and other medical fields. The transcondylar approach has been used in surgeries to access lesions in areas close to the foramen magnum (FM) and is performed directly through the occipital condyle (OC).
This study aims to characterize the foramen magnum shape and contour and determine of the different anatomical variations through the use of reconstructed helical CT images. For verify the morphological characteristics of the (FM) for gender determination in Sudanese individuals by measuring the saggital, transverse diameter, area, circumference and characterizing its shape, and to characterize the anatomical variations related to the (OC) measurements.
A total of 241 Sudanese patients (147 males and 94 females) with mean ageswere 40.96±15.21, 41.02±14.32 years respectively were examined using reformatted axial CT and three-dimensional CT, between September 2012 and July 2014, referred to the Radiology Department in the Ibn ALhythm Medical Center, Khartoum, Sudan
The foramen magnum shapes were determined as a round shape in 55(22.9%) of the cases, oval in 115 (47.8%), irregular in 36(14.8%) and arrow head in 35(14.5%), the mean sagittal and transverse diameters of the foramen magnum were determined as 34.0±2.98 mm and 29.3±2.44 mm respectively. Area of the (FM) was 770.0±111.09 and Circumference of the (FM) was 104.1±11.55, a significant difference between genders were detected at p-value =0.05.Characteristics of the head, and measures related to the (FM) and right and left occipital condyles were examined. The results showed no significant difference between the measurements obtained in the right and in left sides. The (OC) morphometric parameters had significant relationship with (FM) antroposterior and transverse diameters. The study revealed a significant difference between the two genders with no significant relations between (OC) and head characteristics. The data obtained by three-dimensional CT images are important in assessing the morphometric variations of (OC) for Sudanese patients. As the (OC) is the main bony eminences impeded the anterolateral surface of the brainstem, neurosurgeons should be familiar with variations of the (OC) and structures surrounding the (FM) in order to achieve the safest surgical procedure.
knowledge of FM area‘s anatomy is of extreme importance for treating lesion and help the surgeon regarding selection best surgical approach and expected changes in the anatomy of these critical structures and resection of tumors; removal of bony structures such as the occipital condyle (OC) may result in injury to the vascular structures and lower cranial nerves and result in craniocervical instability.
