The human hart is in most cases vascularized by two coronary arteries, the right and the left one. Supernumerary or added coronary arteries are also present sometimes. The aim of this paper is to ascertain presence of supernumerary coronary arteries that arise directly from aorta, their frequency, flow, way of branching, and possibly their anastomoses with other coronary arteries. Out of 25 hearts, examined by dissection, 8 of them (32%) had conal artery. According to our opinion, the most suitable term for this artery, in order to differ it clearly from the conal branch of the right coronary artery, is third coronary artery. One heart (4%) had four coronary arteries. Both supernumerary coronary arteries arose from the right aortic sinus. The third coronary artery represents a significant way of collateral coronary circulation, as it frequently anastomoses with anterior interventricular branch.

Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the "tunnel" segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. Th e studied material contained  human hearts received from the Department of Anatomy. Th e hearts were preserved  to  days in  formalin solution. Th ereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. Th e angle between the myocardial bridge fi bre axis and other axis of the crossed blood vessel was measured by a goniometer. Th e presence of the bridges was confi rmed in . of the researched material, most frequently (.) above the anterior interventricular branch. Th e mean length of the bridges was .±. mm and the mean thickness was .±. mm. Myocardial bridge fi bres pass over the descending blood vessel at the angle of - degrees. Th e results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the diff erence is not signifi cant in relation to bridges located on other branches. Th e results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel.

Proficiency in the anatomy of coronary arteries and their variations is significant for proper interpretation of the coronary angiographies, assessment of the complexity and result of the coronary insufficiency as well as surgical myocardium revascularization. The objective of this study is anatomy-radiology research of the methods of branching the main trunk of left coronary artery and to prove importance of the diagonal branch (ramus diagonalis) existence in the conditions of coronary insufficiency. In this study we have analyzed 100 coronary angiographies done at the Clinic for Heart Diseases and Rheumatism of the Clinic Center of University of Sarajevo and dissected 20 human hearts from the Institute of Anatomy. In our study we have come upon two methods of branching of main trunk of left coronary artery (bifurcation and trifurcation). By the method of the angiography we have found the bifurcation in 71% of cases while 65% of cases were proved by the dissection method. Trifurcation has been discovered in 29% of cases of analyzed angiographies i.e. 35% of cases of dissected hearts. We believe that third terminal branch of the left coronary artery should be marked as ramus diagonalis. This branch, including its anastomoses, presents important pattern of the collateral blood flow, which has special meaning, under conditions of coronary insufficiency.

Microsurgical procedures are the treatment of choice of peripheral nerve injuries, but often fail to reach full functional recovery. Melatonin has neuroprotective actions and might be used as a possible proregenerative pharmacological support. Therefore, the aim of this study was to analyze the time-dependence of the neuroprotective effect of melatonin on the overall fascicular structures of both ends of the transected nerve. Sciatic nerve transection was performed in 34 adult male Wistar rats divided in four groups: two vehicle groups (N=7) treated intraperitoneally for 7 (V7) or 21 (V21) consecutive days with vehicle (5 % ethanol in Ringer solution) and two melatonin groups (N=10) administered intraperitoneally 30 mg/kg of melatonin for 7 (M7) or 21 (M21) consecutive days. At the end of the experiment, proximal stump neuroma and distal stump fibroma were excised and processed for qualitative and quantitative histological analysis. Intrafascicular neural structures were better preserved and the collagen deposition was reduced in the melatonin treated groups than in the vehicle groups. Myelin sheath regeneration observed through its thickness measurement was statistically significantly (p<0,05) more pronounced in the M21 (1,23±0,18 µm) vs. V21 group (0,98±0,13 µm). The mean volume density of the endoneurium was lower in both melatonin treated groups in comparison to the matching vehicle treated groups. Although not statistically different, the endoneural tube diameter was larger in both melatonin groups vs. vehicle groups, and the effect of melatonin was more pronounced after 21 days (24,97 % increase) vs. 7 days of melatonin treatment (18,8 % increase). Melatonin exerts a time-dependent proregenerative effect on nerve fibers in the proximal stump and an anti-scarring effect in both stumps.

Myocardial bridges are inborn anomalies frequently found in authopsies. Although tipically clinically silent, they are occasionally associated with severe clinical manifestations, e.g. myocardial ischemia or even sudden death. The pathophysiology and risk factors for these manifestations have not yet been completely elucidated. The connective tissue underneath the bridge has been considered as one of the factors the symptoms depend on. Thus, the aim of this research was to determine the histological characteristics of the connective tissue lying underneath the myocardial bridge and to contribute to a better understanding of the protective effects this passive compartment might have in prevention of severe clinical manifestations of myocardial bridging. The study was carried out on twenty hearts with myocardial bridges. Length of the bridge was determined using a precise electronic caliper. Sections of the myocardial bridges with the underlying connective tissue were obtained and prepared for qualitative and quantitative analysis. The connective tissue underneath the bridges was composed of adipose tissue and loose connective tissue in different ratios. The tissue underneath thin bridges was predominantly composed of adipose tissue, while loose connective tissue was the dominant component under thick bridges. The myocardial bridges had an average thickness of 0,98 ± 0.44 mm and an average length of 15,25±5,65 mm. We found a strong positive correlation between the myocardial bridge thickness and length (r = 0,860, p = 0,0001). The thickness of the passive connective tissue compartment under the myocardial bridges was 0,58±0,22 mm, and there was no correlation between this parameter and the myocardial bridge thickness (r = -0,011; p = 0,963). In the clinical evaluation of patients with these anomalies it is necessary to take into account independently the myocardial bridge thickness and length on one side and the thickness of the connective tissue lying underneath it on the other.