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Introduction The middle meningeal artery (MMA) is a common target for embolization. MMA tortuosity can complicate the distal delivery of microcatheters, where liquid embolic injection is safest. Risk factors for arterial tortuosity, such as age and hypertension, have been described, but none of these have been evaluated on the MMA, and quantitative morphological studies of this artery have not been performed.Methods Consecutive diagnostic cerebral angiograms from a single center were reviewed. Studies were included if a selective external carotid artery (ECA) angiogram was performed in PA and lateral projections on at least one side. Three previously described tortuosity metrics were evaluated for the frontal and parietal MMA branches on each side: tortuosity index (TI), sum-of-angles method (SOAM), and inflection count metric (ICM). For all three metrics, higher values indicate more tortuosity. Multivariable models were used to determine whether demographic and clinical factors were associated with any of the tortuosity metrics.Results A total of 53 selective ECA injections on 49 patients (mean age 56.9 years, 36.7% female) were included. The most common indication for DSA was intracranial hemorrhage (62%). The mean diameter of the frontal branch (1.28 mm) was significantly larger than that of the parietal branch (1.13 mm; p = 0.008). There was greater tortuosity in the frontal branch than the parietal branch, with significantly higher mean TI (TIfrontal 1.16, TIparietal 1.08; p < 0.001), SOAM (SOAMfrontal 5.1, SOAMparietal 2.77; p < 0.0001), and ICM (ICMfrontal 6.75, ICMparietal 3.73; p < 0.001). In the multivariate models, increasing age was not associated with TIfrontal but was associated with greater SOAMfrontal (p = 0.016) and ICMfrontal (p = 0.004). None of the other factors were associated with frontal branch tortuosity, and none of the factors, including age, were associated with any of the parietal branch tortuosity metrics.Conclusion In our cohort, the frontal MMA branch was typically larger and more tortuous than the parietal branch. Similar to other arteries, age was associated with greater tortuosity, but this was only observed in the frontal branch. Larger multi-institutional studies are required to confirm these findings.Disclosures U. Abdul: None. N. Manalil: None. H. Hoffman: None.