The sciatic nerve in human cadavers - high division or low formation?

Variations of the sciatic nerve have been extensively studied in the past including its relationship with the piriformis muscle and associated clinical conditions like piriformis syndrome and sciatica. In the present study we noticed some interesting variations of the sciatic nerve, which were slightly different from the cases described earlier. In the previous studies most of the authors described the higher division of sciatic nerve and none of them discussed its formation. In this study we tried to look its formation from the sacral plexus and its divisions in the thigh. We noticed that in one cadaver the two components of the sciatic nerve originated directly from the sacral plexus and coursed down without merging in the thigh. Should this be called a higher division or non formation of the sciatic nerve? On the other hand in two other cadavers, the two divisions after emerging separately from the sacral plexus, united in the gluteal region and in the thigh respectively. Should we call this as higher division or low formation of the sciatic nerve? In two other cadavers the sciatic nerve emerged from the greater sciatic foramen below the piriformis and divided in the gluteal region itself. Ideally this should be called as higher division of sciatic nerve.

Unusual presence of Wormian (sutural) bones in human skulls.

Wormian bones are a subset of the small intrasutural bones that lie between the cranial sutures formed by the bones of the skull vault. They are formed due to additional ossification centres in or near sutures. They are usually considered as normal variants and seem to be determined genetically in certain populations. They have been linked with rapid cranial expansion as they appear in great number in hydrocephalic skulls. They are commonly found in the lambdoid suture and fontanelles but are occasionally seen in other sutures especially the coronal, squamosal, and sagittal sutures. We examined 25 dried human skulls with the aim to find out the occurrence and variations of Wormian bones, and surprisingly we found Wormian bones in the coronal, squamosal, and sagittal sutures in 6 skulls. These are uncommon sites of occurrence of sutural bones as reported in the literature. These findings prompted us to report these cases as their presence can lead to confusion in diagnosis in cases of skull fractures.

How the three arches of the foot intercorrelate.

BACKGROUND: The foot is composed of medial, lateral and transverse arches which, particularly the medial arch, provide it with the ability to function both as a flexible and rigid structure for proper locomotion. Arches of the foot, as well as their effect on lower extremity function, have been studied. However, quantitative data on the relationship between these arches still remain scanty. The purpose of this study was, therefore, to examine how the three arches of the foot intercorrelate. MATERIALS AND METHODS: Seventy-six participants (58 males, 18 females) were recruited to participate in the study. Bilateral weight-bearing lateral radiographs of the right foot were taken from each participant. Navicular heights (NH), medial cuneiform height (MCH), calcaneal inclination angle (CIA) and calcaneal-first metatarsal angle (C1MA) were measured to represent the medial arch. The lateral arch was represented by cuboid height (CH) and calcaneal-fifth metatarsal angle (C5MA) whereas; MCH and CH represented the transverse arch. Mean difference of variables between males and females was compared using independent t-test while the correlation between the variables was determined using Pearson correlation. RESULTS: All the variables were not significantly related to gender. Significant moderate to excellent linear correlations were observed between the variables. CIA showed the strongest correlation with C1MA (r = -0.90) and C5MA (r = -0.84) whereas, CH had the least correlation with other variables. CONCLUSIONS: The moderate to excellent correlations between the variables indicate that deformation or elevation of the medial arch may consequently result in similar movements of the lateral and transverse arches and vice versa.