Background and Objectives: The landmark for neurosurgical approaches to access brain lesion is the pterion. The aim of the present study is to classify and examine the prevalence of all types of pterion variations and perform morphometric measurements from previously defined anthropological landmarks. Materials and methods: One-hundred and twenty-four Thai dried skulls were investigated. Classification and morphometric measurement of the pterion was performed. Machine learning models were also used to interpret the morphometric findings with respect to sex and age estimation. Results: Spheno-parietal type was the most common type (62.1%), followed by epipteric (11.7%), fronto-temporal (5.2%) and stellate (1.2%). Complete synostosis of the pterion suture was present in 18.5% and was only present in males. While most morphometric measurements were similar between males and females, the distances from the pterion center to the mastoid process and to the external occipital protuberance were longer in males. Random forest algorithm could predict sex with 80.7% accuracy (root mean square error = 0.38) when the pterion morphometric data were provided. Correlational analysis indicated that the distances from the pterion center to the anterior aspect of the frontozygomatic suture and to the zygomatic angle were positively correlated with age, which may serve as basis for age estimation in the future. Conclusions: Further studies are needed to explore the use of machine learning in anatomical studies and morphometry-based sex and age estimation. Thorough understanding of the anatomy of the pterion is clinically useful when planning pterional craniotomy, particularly when the position of the pterion may change with age.

Amnart Chaichun, Laphatrada Yurasakpong, Athikhun Suwannakhan, Sitthichai Iamsaard, Supatcharee Arun, Arada Chaiyamoon. Anat Cell Biol 2021;54:280-4. https://doi.org/10.5115/acb.20.323

Chronic stress (CS) is shown to decrease the semen quality with changed expression of tyrosine phosphorylated (TyrPho) proteins in testicular and seminal tissues. However, the alterations of such proteins and fluid contents in the epididymis, producing sperm maturation factors, have never been reported. Sixteen adult rats were randomly divided into 2 groups (n = 8). The control animals were not subjected to stressors whereas CS rats were immobilised within restraint cage (4 hr/day) before cold forced‐water swimming (15 min/day) for 60 days. Corticosterone, testosterone, blood glucose level (BGL), malondialdehyde (MDA) and biochemical components in epididymal fluid were assayed. Expressions of heat shock protein 70 (HSP‐70), androgen receptor (AR) and TyrPho protein were investigated in epididymal tissue and fluid. Significantly, CS increased the corticosterone and BGL but decreased testosterone and epididymal substance levels. MDA level in tail epididymal fluid and HSP‐70 expression in both regions of epididymal tissues and fluids, except in head epididymal fluid of CS were increased. Epididymal tissues showed the decrease of AR expression. Presence and changes of many TyrPho proteins were observed in CS. In conclusion, CS could affect functional proteins particularly TyrPho in epididymis, resulted in low semen quality.