Morphologic characterisation of the posterior inferior cerebellar artery. A direct anatomic study.

BACKGROUND: The number of studies on the cerebellar arteries has increased. The purpose of this study was to determine the morphological expression of posterior inferior cerebellar artery in a sample of Colombian population. MATERIALS AND METHODS: One hundred eighty-six posterior inferior cerebellar arteries of fresh cadavers were studied. In each specimen, vertebral arteries were injected with 100 mL of semi-synthetic resin, dyed with mineral red. RESULTS: In the 93 blocks of brainstem and cerebellum evaluated, 174 (93.5%) posterior inferior cerebellar arteries were found. Also, there were 12 (6.5%) ageneses. There was single posterior inferior cerebellar artery in 159 (91.4%) samples and duplicate in 10 (5.7%), while 5 (2.9%) specimens showed hypoplasia. The posterior inferior cerebellar artery originated from the vertebral artery in 121 (69.5%) samples and from the basilar artery in 42 (24.1%) samples; while in 11 (6.4%) it originated in a common trunk with the anterior inferior cerebellar artery. In 101 (83.5%) cases, the posterior inferior cerebellar artery originated from the intracranial segment of the vertebral artery, while 20 (16.5%) samples originated from the extracranial segment. The calibres of posterior inferior cerebellar artery in its proximal and distal segments were 1.45 ± 0.37 mm and 1.33 ± 0.31 mm, respectively. CONCLUSIONS: This study, carried out in cadaveric material, provides relevant qualitative and morphometric information of the posterior inferior cerebellar artery, useful for the diagnosis and clinical management, as well as for the surgical approaches that may compromise this structure.

Histological and morphometric study of the components of the sinus and atrioventricular nodes in horses and dogs.

The cardiac nodes are the source of the electrical impulse that is transmitted to the heart, the aim of this work is study the histological and morphometric characteristics of the different components of the sinus and atrioventricular nodes in horses and dogs that help to know the physiopathology of these nodes. A group of ten horse hearts and five dog hearts were used. The region of the sinus and atrioventricular nodes was sectioned serially, and the block of tissue removed for study. The samples were assessed using a morphometric analysis with the Image-Pro Plus 7.1 software and the acquisition of the images using a Leica DMD108 optic microscope. The shape of the horse's sinus node is oblong and its P cells are large. The shape of the dog's sinus is rounded or oblong. The P cells are large and pale. The area of P cells in horses was 976 (SD 223.7) µm2 and in dogs the area for P cells was 106 (SD 30.4) µm2, which indicates that the value for P cells in horses are significantly higher than in dogs (p = .001). The horse atrioventricular node presented an oblong shape and in dogs, presents a spindle shape. The lower cell density in any of the cardiac nodes, especially in P cells of sinus node, can decrease electrical conduction within the nodes and in the internodal tracts, which would reflect the presence of cardiac arrhythmias derived from poor conduction, even in morphologically normal hearts.

[Morphological characteristics of cerebral aneurysm of Willis' circle: a direct anatomical study]. / Características morfológicas de aneurimas cerebrales del polígono de Willis: estudio anatómico directo.

OBJECTIVE: To determine the prevalence and morphologic characteristics of unruptured aneurysms of Willis' circle in a sample of mestizo Colombian population. MATERIALS AND METHODS: A mixture of resin and mineral red was injected into cerebral arteries by dissection and canalization of common carotids and vertebral arteries of the encephalons of 125 mestizo male cadavers of 16 to 65 years old. The procedure was carried out during the autopsy course at the Legal Medicine Institute, Bucaramanga - Colombia. Then the encephalons were extracted and fixed. After that, the Willis' circles were identified and the presence of aneurysms at this level was determined with magnifying glass. RESULTS: A total of nine aneurysms were observed in six brains (4.8%). The most frequent location was the supraclinoid segment of the intern carotid artery, with 4 cases (44.4%), three of which were localized in the origin of the anterior choroidal artery. Additionally, three aneurysms were found in the anterior communicating artery (33.3%). From the remaining cases, one (11.1%) was localized in the pre-communicating segment of the anterior cerebral artery, and the other in the bifurcation of the basilar artery. The average size of the aneurysms was 2.49 mm SD 0.37. The affected encephalons presented concomitant variations of the Willis' circle configuration, being predominant the presence of hypoplasic posterior communicanting arteries. CONCLUSION: The aneurysm prevalence in the evaluated sample was similar to the reported in other populations. In this work, the presence of aneurysms on the origin of the anterior chorioid artery, an unusually reported localization, was prominent.