Cranioscopic and craniometric characteristics of the adult neurocranium in normal and deformed states

BACKGROUND: Modern craniological studies should be based on an integrated approach and include algorithms to distinguish between normal and pathological conditions. It is essential to determine the extent to which craniometric parameters of deformed skulls deviate from normal values.

AIM: This study aimed to examine the cranioscopic and craniometric characteristics of the neurocranium in normal and deformed states based on the Dolgo-Saburov collection preserved in the Fundamental Museum of the Department of Normal Anatomy, S.M. Kirov Military Medical Academy; to determine the prevalence of cranial deformations; and to develop criteria for the design of contemporary craniological studies.

METHODS: A series of 842 skulls was examined. The condition of cranial sutures was assessed, with identification of craniosynostosis and associated abnormal cranial forms, as well as asymmetry of the neurocranium and its relationship to craniosynostosis. For craniometric determination of neurocranial shape, longitudinal (Martin 1), transverse (Martin 8), and vertical (Martin 17) diameters were measured. The estimated cranial cavity volume was calculated, along with the transverse–longitudinal (cranial), height–length, and height–breadth indices.

RESULTS: Of the examined series, 678 skulls were classified as normal, with no deformations, asymmetry, or developmental anomalies. The majority of skulls were brachycranial or mesocranial based on the cranial index (55.8% and 39.2%, respectively); hypsicranial and orthocranial based on the height–length index (46.5% and 44.1%, respectively); and tapeinocranial and metriocranial based on the height–breadth index (44.4% and 47.9%, respectively). Deformations were observed in 164 skulls, which were divided into three groups: skulls with premature closure of one or more cranial vault sutures (2.6%); asymmetric skulls without signs of premature synostosis (16.1%); and skulls combining abnormal craniosynostosis with asymmetry (1.2%). The first group included two subgroups: skulls with sagittal craniosynostosis (scaphocephaly) and skulls with combined premature coronal and sagittal synostosis (oxycephaly). Scaphocephalic skulls (1.1%) were pathologically elongated and narrow, often with a saddle-shaped cranial vault deformity. In contrast, oxycephalic skulls were short with high height–length indices. For such skulls, we propose the term “pathological hypsibrachycrany.” In plagiocephaly (cranial asymmetry), the occipital, parietal, and frontal regions were shifted in opposite directions, with left-sided asymmetry more common (58.5%).

CONCLUSION: The distribution of normal skulls by cranial index confirms the evolutionary trend toward brachycephalization. Dolichocranial, chamaecranial, and acrocranial skulls are the least common forms (< 10%). Premature suture closure does not always lead to marked cranial deformities. This work provides detailed characteristics of deformed skulls and highlights situations in which standard indices may be inappropriate. Craniometric measurements should be performed only after cranioscopic evaluation for craniosynostosis and asymmetry.