Marcos Pérez-Riffo; Marión Verdugo-González; Francisco J. Pérez-Rojas & Enrique Olave
The transverse basilar cleft (TBC) is a rare anomaly of the skull base, attributed to incomplete ossification of the basioccipital bone during early embryonic development. Its reported prevalence is low (<1 %) in modern osteological collections; although it may be underestimated due to incidental detection and variability in the diagnostic criteria used. The objective of this study was to report an anatomical case of TBC in an adult skull, describe its morphological characteristics, and discuss its possible embryological origin and clinical relevance in light of the current scientific literature. To this end, a descriptive study was conducted through a systematic review of 150 adult human skulls from the anatomical collection of the Universidad Católica del Maule, Chile. A specimen was identified with an incomplete bilateral TBC located at the level of the pharyngeal tubercle, with no signs of trauma or remodeling, suggesting a congenital origin. Physical measurements were taken using a digital caliper, and a comparative analysis was performed with previous morphological references. Regarding the recorded dimensions, the prebasioccipital exhibited a width of 20.57 mm and an anteroposterior length of 13.76 mm, while the basiocciput measured 25.30 mm in width and 10.53 mm in anteroposterior length. The left cleft measured 9.08 mm, the central intact bony segment 8.04 mm, and the right cleft 8.07 mm. This report expands the current knowledge on basioccipital variations and provides anatomical evidence that may be useful in clinical, neurosurgical, and anthropological studies. It also highlights the need to continue documenting similar cases to better understand their prevalence and developmental origins.
KEY WORDS: Skull base; Occipital bone; Anatomic variations; Congenital abnormalities; Transverse Basilar Cleft.
PÉREZ-RIFFO, M.; VERDUGO-GONZÁLEZ, M.; PÉREZ- ROJAS,F.J.&OLAVE,E. Transversebasilarcleft:Casereport, morphological and embryogenic review. Int. J. Morphol., 44(1):319-324, 2026.
