The Sequence in Appearance and Disappearance of Impressiones Gyrorum Cerebri and Cerebelli

We investigated the sequence and the intensity in the appearance and the disappearance of the impressiones gyrorum cerebri and cerebelli, of juga cerebralia and cerebellaria and of juga cerebellaria interlobularia in the collection of 34 macerated and disarticulated skull bones from the newborn to 30 years of age (68 specimens/halves of skulls) and 19 skulls in the period from 30 to 80 years of age (38 specimens). Juga cerebralia on the squama of the temporal bone and cerebral lamina of the frontal bone appeared already in the course of the first year of life, much earlier than cited in the literature. The intensity of the development of juga cerebralia increased to the third decade. After that age, the intensity decreased gradually, and the juga cerebralia disappeared completely in parietal bones, in the cerebral fossae of the occipital bones and finally in most cases also on the cerebral lamina of the frontal bones. Juga cerebellaria and impressiones gyrorum cerebelli appeared in the middle of the second year of age and persisted to the ten years of age, which coincides with the closure of the fissures among the parts of the occipital bone. Jugum cerebellare intersemilunare appeared in the first year of life and persisted in its complete length, or interrupted in different sections of its course, during the whole life. The intensity in appearance of juga is partly influenced by the increasing thickness of the diploe

Morphological characterization of the posterior ethmoidal and additional ethmoidal canal in adult Croatian population

The anterior and posterior ethmoidal foramina that open into canals entering the cranial cavity are situated on the medial orbital wall. Since there may be a variable number of accessory ethmoidal foramina and their anatomy appears to be dependent on studied population, we are presenting a study of frequency and morphological characteristics of posterior and additional ethmoidal canals in adult Croatian population. In this study 439 skulls from the Zagreb skull collection were examined in order to confirm the existence of the posterior ethmoidal canal that opens in the anterior cranial fossa and the additional ethmoidal canal that opens in ethmoidal cells. Length and width of both canals were analyzed on computerized tomography scans using Analyze 8.1. software. The posterior ethmoidal canal was found in 86% of skulls. In 10% of skulls the posterior and the additional ethmoidal canals were found.  In 4% of skulls we found only the additional ethmoidal canal. On skulls that had the additional ethmoidal canal the posterior ethmoidal canal was shorter and narrower. Variations in communications between orbital cavity and anterior cranial fossa, as well as ethmoidal and sphenoid sinuses could be related to increased need for vascular and nerve supply. Moreover, knowing anatomical variations of the posterior ethmoidal canal is crucial for development of safe surgical and therapeutic guidelines both in orbital and cranial regions. Based on observed communications, we suggest the revision of commonly used nomenclature for the anterior and posterior, as well as additional ethmoidal canals.