Pterional variable topography and morphology. An anatomical study and its clinical significance.

BACKGROUND: Pterion is the junction of the frontal, parietal, greater wing of the sphenoid and the squamous part of the temporal bone. The sphenoparietal, frontotemporal, stellate and epipteric pteria were described. The current study determines pterion topography, morphology (variant types' frequency) and morphometry, as well as epipteric bones presence in dried skulls. Gender impact is underlined as well. MATERIALS AND METHODS: Ninety Greek adult dried skulls were observed. The distances in between pterion and the zygomatic arch midpoint and in between pterion and the frontozygomatic suture were measured. RESULTS: The sphenoparietal pterion was the commonest (58.3%), following by the stellate (25%), epipteric (15.5%) and by the frontotemporal pterion (1.1%). Twenty-eight (15.5%) skulls had epipteric bones, further categorised as quadrisutural (35.7%), trisutural (57.1%), bisutural and multiple (3.57%). The mean distances between pterion and the midpoint of zygomatic arch were 4.13 ± 0.45 cm on the right and 4.09 ± 0.47 cm on the left side and between pterion and the frontozygomatic suture were 3.47 ± 0.61 cm on the right and 3.52 ± 0.65 cm on the left side. Both distances were symmetrical. Male skulls showed slightly higher values on the left side for the distance (pterion-midpoint of zygomatic arch). CONCLUSIONS: Pterion is a commonly used neurosurgical landmark and thus in depth knowledge of the pteric area and its variants could be valuable. Recognition of the possible variability in pterion location, morphology and morphometry, as well as possible occurrence of epipteric bones may render pterional craniotomy safer among different population groups.

Quality of placental RNA: Effects of explant size and culture duration.

We evaluated the impact of placental micro (≤50 mg) and macro (∼200 mg) explants, oxygen concentration and culture method on placental RNA quality after long-term culture. Our findings show that micro explants cultured at 8% oxygen have the best RNA quality and tissue structure. Macro explants were less viable after long-term culture. Macro explants and explants undergoing syncytial degeneration produced poor quality RNA and should be avoided.