Anatomical Differences in the Cranial Cavity and their Impact on Neurological Health: A Systematic Review

The cranial cavity exhibits significant anatomical diversity, with consequences for neurological function through the modification of intracranial pressure, cerebral perfusion, and neurovascular interactions. Cranial structural diversity has been linked to the pathophysiological processes of neurodevelopmental disorders, cerebrovascular disease, and neurodegenerative disease. The extent to which these anatomical diversities influence neurological health is uncertain. This systematic review was undertaken to combine the existing evidence on cranial cavity variations and their association with neurological outcomes. A comprehensive search of seven databases was conducted to identify cross-sectional studies, case-cohort studies (retrospective and prospective designs), and clinical trials that have investigated cranial cavity morphometry and its neurological importance. Quantitative data on cranial cavity measurements and their relationship with measures of neurological well-being provided by studies were utilized. Potential for bias was assessed using the Joanna Briggs Institute systematic review checklist. Synthesis of data was a systematic analysis of variables such as cranial volume, skull base angulation, cortical thickness, ventricular size, and related neurological parameters. The findings indicated significant interindividual and condition-dependent variation in cranial cavity structure. Cranial volume ranged from 950 to 1200 cm 3 , with deviations in the cases of craniosynostosis and Chiari malformation. Skull base angles varied between 124° and 134°, with alterations associated with osteogenesis imperfecta and platybasia. Ventricular enlargement was associated with cognitive impairment, with affected individuals exhibiting a 2.3% greater ventricular occupancy compared with controls ( P < 0.01). Cortical thickness reductions were significant in neuropsychiatric disorders, with thinning observed at rates of up to 50% relative to controls ( P < 0.05). Gray-to-white matter ratio had profound predictive value for neurological outcome, with a threshold range of 1.17–1.27 exhibiting a sensitivity of 85% and specificity of 90%. Preservation of cerebral perfusion pressure above 70 mmHg was associated with favorable survival, though not statistically significant ( P = 0.08). Overall risk of bias was low-to-moderate throughout the included studies. Anatomical variations in the structure of the cranial cavity demonstrated quantifiable correlations with neurological well-being, specifically with respect to cerebrovascular surgery, intracranial pressure, and mental function. They highlighted the need for the incorporation of cranial morphometric assessment into neurological evaluation to enhance diagnostic and prognostic strategies. Longitudinal studies and sophisticated imaging techniques should be the focus of future studies to establish causal relationships between anatomical variation and neurological disease.