Anat Cell Biol.  2023 Sep;56(3):342-349. 10.5115/acb.23.006.

Clinical and anatomical importance of foramen magnum and craniocervical junction structures in the perspective of surgical approaches

• Demir BT
• Eşme S
• Patat D
• Bilecenoğlu B

• KMID: 2546462
• DOI: http://doi.org/10.5115/acb.23.006

Abstract

This study was conducted to investigate the clinical and anatomical importance of the relevant region from the perspective of surgical approaches by determining the morphometric analysis of the craniocervical junction and foramen magnum (FM) region and determining their distances from important anatomical points. This research was carried out with 59 skulls found at the Anatomy Laboratories of Erciyes and Ankara Medipol University. Metric measurements of FM and condyle, FM shape, condyle-fossa relationship, and pharyngeal tubercle (PT) were made in mm-based dry bone samples of unknown age and sex. The distance between the anterior notches and the FM was 87.01±4.35, the distance between the anterior notches and the PT was 77.70±4.24, the distance between the PT-sphenooccipital junction was 13.23±2.42, and the FM index was 81.86±7.47. The anteroposterior and transverse lengths of FM were determined as 33.80±2.99 and 27.72±2.30, respectively. The morphometric and morphological data available regarding the craniocervical junction showed significant differences between populations. Comprehensive knowledge of this topic will provide a better approach to treat Arnold Chiari Malformation, FM meningiomas, and other posterior cranial fossa lesions. Therefore, we believe that FM and craniocervical junction morphology will be a guide not only for anatomists, but also for radiologists, neurosurgeons, ENT surgeons, and orthopedists.

Keyword

Foramen magnum; Craniocervical junction; Morphometry; Transoral/transpharyngeal approach

Figure

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  Fig. 1 Posterolateral, transoral and transpharygeal approaches. Adapted from Luzzi et al. (Turk Neurosurg 2019;29:875-86) [7].

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  Fig. 2 Morphological measurements of foramen magnum (FM) and occipital condyle (OC). (A) 1: FM anteroposterior length, 2: FM transverse length, 3: OC length, 4: OC width. (B) f1: the distance from the anterior midpoint of the FM to the most protruding point of the medial edge of the OC, f2: posterior of the FM distance from its midpoint to the most protruding point of the medial edge of the OC, f3: from the anterior midpoint of the FM to the midpoint of the medial edge of the OC, f4: from the posterior midpoint of the foramen magnum to the midpoint of the medial edge of the occipital condyle.

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  Fig. 3 Relationship of PT with key points. 1: distance between anterior notchs-medial of FM, 2: distance between anterior notchs-TP, 3: distance between PT-sphenooccipital junction, 4: distance between PT-ala of vomer, 5: distance between PT-basion. PT, pharyngeal tubercle; FM, foramen magnum.

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  Fig. 4 Angles associated with FM. p1: angle between anterior notchs and lateral of occipital condyle (AN-OC/L), p2: angle between anterior notchs and medial of occipital condyle (AN-OC/M), p3: anterior notchs angle between mastoid process (AN-MP), p4: sagittal intercondylar angle (SIA), p5: sagittal condylar angle (SCA).

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  Fig. 5 Foramen magnum (FM) shapes. (A) FM shapes, (B) percentages of FM shapes.

Reference

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