The persistent primitive trigeminal artery, as the most commonly carotid-vertebrobasilar anastomosis, has a reported incidence of 0.03-2.2% in the literature. There is female sex predilection, and it may be discovered in patients of any age, on either side, and in association with many vascular variants. Although the significance of persistent primitive trigeminal artery regarding the development of an aneurysm or association with another pathological condition may not be clear, its (ab)normal morphology is the inspiration for anatomists, especially for neurosurgeons, before planning diagnostic and therapeutic procedures.

We noted a predisposition of males older than 40 years to arterial dolichoectasia in the vertebrobasilar system, independently from population group, as well as its asymptomatic appearance, independently from the presence of atherosclerotic plaques.

One of the most common complications of diabetes mellitus is diabetic neuropathy. It may be provoked by metabolic and/or vascular factors, and depending on duration of disease, various layers of nerve may be affected. Our aim was to investigate influence of diabetes on the epineurial, perineurial, and endoneurial connective tissue sheaths. The study included 15 samples of sural nerve divided into three groups: diabetic group, peripheral vascular disease group, and control group. After morphological analysis, morphometric parameters were determined for each case using ImageJ software. Compared to the control group, the diabetic cases had significantly higher perineurial index (P < 0.05) and endoneurial connective tissue percentage (P < 0.01). The diabetic group showed significantly higher epineurial area (P < 0.01), as well as percentage of endoneurial connective tissue (P < 0.01), in relation to the peripheral vascular disease group. It is obvious that hyperglycemia and ischemia present in diabetes lead to substantial changes in connective tissue sheaths of nerve, particularly in peri- and endoneurium. Perineurial thickening and significant endoneurial fibrosis may impair the balance of endoneurial homeostasis and regenerative ability of the nerve fibers. Future investigations should focus on studying the components of extracellular matrix of connective tissue sheaths in diabetic nerves.

Results of this study will be the basis for future investigation of CACs according to the same or different ages and causes of disease and/or death.

The frequency, segment, and side location, as well as the size and shape of PCA fenestrations in specimens of our population did not significantly differ from the same in other populations. PCA fenestrations in our adult specimens were not the bases of aneurysms.