Radiological and anatomical evaluation of the posterior condylar canal, posterior condylar vein and occipital foramen

Abstract

Objectives: This study was carried out to make morphometric and radiological analyses of the occipital foramen (OF), posterior condylar canal (PCC), posterior condylar vein (PCV), and occipital emissary vein (OEV). Methods: Morphometric analyses were performed on 91 adult human occipital bones and radiological analyses on computed tomography (CT) angiography images of 221 patients. PCC length and mean diameters of the internal and external orifices of PCC were measured and the number of OF on both sides was recorded for bony specimens. Prevalence of PCV and PCV size were investigated using CT angiography. Results: PCCs were observed in 60 bones (66%) on the left and 60 bones (66%) on the right side. Mean PCC length was 10.85 ±3.41 and 9.77±3.55 on the left and right sides, consequently. Mean internal orifice diameter was 3.87±1.99 mm on the left and 3.31±4.43 mm on the right side; mean external orifice diameter was 4.02±1.59 mm on the left and 3.89±1.52 mm on the right side. The majority of PCCs (75%-81.6%) had 2-5 mm diameter; only 5-13.3% were small in size (<2mm). In CT angiography, PCV was not identified in 45(22.5%) patients. PCVs were located bilaterally in 114 (57%) and unilaterally in 41(20.5%) patients. Only 4.3% of PCVs (n=17) were large in size, the majority (27.5%) were medium-sized and 35.8% small-sized. Conclusion: This study will contribute to the limited body of research on OF, PCC, PCV, and OEV as a guide to surgical interventions for pathologies of the posterior cranial fossa such as tumors and injuries. Keywords: computed tomography angiography; emissary vein; occipital foramen; posterior condylar canal; posterior condylar vein