Study of landmarks in dried skulls in a Brazil population

Craniofacial bone variations, considered to be radiological landmarks, have been studied since the beginningof the century using dried skulls and cadavers. These pitfalls are important bone landmarks used in theplanning and execution of anesthetic and surgical procedures. The present study analyzed craniofacial bonevariations in dried skulls in terms of gender and laterality. Supraorbital foramen (SOF), mastoid foramen(MF), parietal foramen (PF), accessory oval foramen (aOF), anterior ethmoidal foramen (AEF), intermediateethmoidal foramen (iEF), posterior ethmoidal foramen (PEF), precondylar tubercle (PCT), metopism andsutural bones were assessed in male (n=20) and female (n=11) dried skulls by direct observation and using aMitutoyo caliper. No statistically significant differences were observed between genders as to SOF distancesto the medial nasal prominence and to superior orbital ridge, in both sides of skulls. The same was observedfor distances between FP and sagittal line and between FP and lambdoid suture. No multiple foramina weredetected. aOF was observed in 80.96% of skulls. Right aEF, iEF and PEF prevailed in female skulls. PCT wereseen in 35.5% of female skulls and in 64.5% of male skulls. MF occurrence was higher in right male skulls,and multiple foramina were present in 60% of male skulls (both sides), and in 36.4% of female skulls (bothsides). Only one skull presented sutural bone. No metopism was observed. The identification and recordingof craniofacial variations is important in the preparation of anesthetic blocks in surgical procedures and in theevaluation of regional neurovascular anatomy, to avoid misinterpretations in planning. This study confirms theexistence of significant morphological variations in terms of gender and side in a given population.

Morphometric analysis related to the transcondylar approach in dry skulls and computed tomography / Análisis morfométrico del acesso transcondilar en cráneos secos y en tomografia computarizada

The transcondylar approach (TA) has been used in surgeries to access lesions in areas close to the foramen magnum (FM) and is performed directly through the occipital condyle (OC) or through the atlanto-occipital joint and adjacent portions of the same. The objective of this study is to examine anatomical variations related to the TA by morphometric parameters of the FM, OC and of the hypoglossal canal (HC) in dry skulls and in computed tomography (CT). In 111 skulls, characteristics of the HC, and measures related to the FM, the HC and to the OC were examined. In CT, the measurements obtained bilaterally in 10 patients who underwent examination of the skull base in 1 mm-thick axial helical cuts were the distances from the outer half of the clivus to the opening of the HC; from the lower portion of the OC to the middle of HC; from the inner half of the clivus to the intracranial opening of the HC and to the midpoint of the HC; from the HC extracranial opening to the lower portion of the OC and to the outer half of the clivus. The results of CT measurements are consistent to previous studies of morphometric variations related to the TA, with no significant difference between the measurements obtained in the right and in the left sides, or related to gender. The data obtained by three-dimensional CT images are important in assessing the morphometric variations of pre-surgical patientsof TA.

El acceso transcondilar (AT)ha sido utilizado comoun procedimiento quirúrgico para lesiones cercanas al foramen magnum(FM)y se realizadirectamente a través delcóndilooccipital (CO)o por medio delas porciones atlanto-occipitalconjuntay adyacentesde lamisma.El objetivo del presenteestudio fue examinarlas variaciones anatómicas relacionadas con el AT mediantelos parámetros morfométricos del FM, CO y el canal delhipogloso (CH) en cráneossecos y tomografía computadorizada (CT). En 111 cráneos fueron examinadas las característicasdel CH y tomadas medidas relacionadas con el FM, CO y CH. En la CT, las mediciones se obtuvieron de forma bilateral en10 pacientes que se sometieron a exámen de la base del cráneo en corte axial helicoidal de 1mm de espesor. Las medidas tomadas fueron las distancias: de la mitad exterior del clivus a la apertura del CH; de la parte inferior de las emisiones de CO a la mitad del CH; de la mitad interna del clivus a la apertura intracraneal del CH y hasta el punto medio del CH; de la apertura extracraneal del CH a la parte inferior de las emisiones de CO y hasta la mitad exterior del clivus. Los resultados de las mediciones de CT son consistentes con estudios prévios de los cambios morfométricos en relación con AT, sin diferencia significativa entre las mediciones obtenidas en el lado derecho e izquierdo y ni en relación con el sexo. Los datos obtenidos a través de imágenes en tres dimensiones de CT son importantes para evaluarlas variaciones morfométricas de pre-quirúrgicos en el AT.