Sex differences in diameter of the coronary sinus ostium: Correlation with weight of the heart

Diameter of the coronary sinus ostium is important in the designing of cannulation devices used in cardiac resynchronization  therapy and percutaneous mitral valve annuloplasty. Population variation of the diameter may account for the failure rate of these procedures. Studies of the coronary sinus ostium from African populations are scarce and altogether absent for Kenya. Therefore, this study aimed at determining sex differences in the diameter of coronary sinus ostium and its correlation with the weight of the heart. Seventy-four hearts of adult black Kenyans [43 male, 31 females; age range 20 – 70 years] obtained during autopsy at the Department of Human Anatomy, University of Nairobi, Kenya were weighed. The coronary sinus ostium was identified and its   transverse and supero-inferior diameters measured in millimeters. The measurements were analyzed using SPSS version 17. Sex  comparison was established using student’s t test. Association between diameter and heart weight was established using  Pearson’s correlation test and considered significant at a p-value of ≤0.05. Data were presented using scatter plots. Transverse and supero-inferior diameters of the ostium were 11.04±1.88mm and 9.50±1.80mm respectively. The mean diameter was 10.27 mm. These correlated positively with weight of the heart. When corrected for weight of the hearts, the transverse and supero-inferior diameters were larger in females (0.042 and 0.036 respectively) than in males (0.034 and 0.03 respectively). The diameter of coronary sinus ostium is larger in females and shows positive correlation with weight of the heart. These data should be considered during design and use of cardiac devices introduced through the coronary sinus.Key words: Coronary sinus, ostium, diameter, sex difference

Regional differences in the mural structure of the human coronary sinus

Regional differences in the mural structure of the coronary sinus are important in understanding its physico-mechanical properties and the basis for extent of atrial  fibrillation and ablation. These features are only scarcely reported. This study  therefore aimed at describing regional differences in the mural structure of coronary sinus among black Kenyans. This was a descriptive cross-sectional study on coronary sinuses from fifteen hearts obtained during autopsy on adult black  Kenyans at the Department of Human Anatomy, University of Nairobi.  Five-millimeter-long specimens were taken from the proximal, middle and terminal segments of the coronary sinus and processed routinely for paraffin embedding and sectioning. Seven-micron thick sections were stained with Masson’s Trichrome to demonstrate connective tissue and smooth muscle while Weigert’s Resorcin  Fuschin stain was used to demonstrate elastic fibres. The slides were examined  with a light microscope and photomicrographs taken with a high resolution digital camera. The results are presented in micrographs. The wall comprised three layers namely internal, middle and external. Regional differences were observed in the middle layer. In the proximal segment, there were concentrically oriented smooth muscles scattered within connective tissue. The middle and terminal segments on the other hand comprised cardiac muscle oriented both concentrically and  longitudinally. The muscle was separated by connective tissue rich in elastic fibres and abundant vasa vasora. The external layer comprised connective tissue. In conclusion the middle layer of the wall of the coronary sinus displays regional  differences. The smooth muscle at the proximal segment may confer contractility to enhance blood flow while the cardiac muscle in the other segments enables it to function in synchrony with the right atrium during atrial systole. The complex  arrangement of circular and longitudinal muscle facilitates blood flow and may also constitute a sphincter mechanism.Keywords: Coronary sinus, regional differences, smooth and cardiac muscl

Anthropometric dimensions of hand and foot as predictors of stature: A study of two ethnic groups in Nigeria

Background: Anthropometry as a science deals with the study of human measurements with a view towards the understanding of physical variations that exist in human population groups. Estimation of stature is very important in the investigation process of unknown and co-mingled human remains in mass casualties and natural disasters. Stature or height therefore is critically essential in human identification.Aim: This study was aimed at determining stature using the anthropometric measurements of hand and foot dimensions in two ethnic Nigerian populations.Methodology: A descriptive cross-sectional study involving 384 Nigerian students selected using random sampling technique was used. These subjects were male and female volunteers of two ethnic groups’ aged between18 and 30 years. Cochran method for sample size determination was used. All measurements of hand and foot dimensions were recorded to the nearest centimetre using standardized anthropometric measuring equipment and the mean actual and estimated stature obtained.Results: The study showed significant gender difference in mean right and left hand breadth but not the mean right and left hand length (P < 0.05). Similarly, there was a statistically significant gender difference between the mean right and left foot breadth (P < 0.05), but not between the mean right and left foot breadth and right foot lengths respectively (P > 0.05). The study further showed that in both gender, that breadth parameters showed stronger correlations in hand and foot dimensions. There was also a significant association between the mean left hand length and right and left hand breadth (P < 0.05) but not with the mean right hand length (P = 0.853). There was also significant association in the mean left foot length and the right and left foot breadths (P < 0.05) but not in the right foot lengths (P = 0.294). The mean estimated value of stature using linear and multiple regression equations for all parameters ranged from 164.53 cm to 165.57 cm while the mean actual stature from the study was 165.30 cm for all the subjects, specifically, 165.90 cm for the Igbos and 164.79 cm for the Isokos respectively.Conclusion: Our study showed that stature can be accurately estimated using all hand and foot parameters and this is of medico-legal importance.Keywords: Anthropometric dimensions, Stature prediction, Ethnic groups, Nigerian

Involvement of multiple cell lineages in atherogenesis

Atherogenesis is a multicellular event. Early reports concentrated on the role of endotheliocytes, monocyte - macrophages and smooth muscle cells. Recognition of the immuno-inflammatory nature of the process, however, expanded the scope of cellular involvement and more recent reviews emphasize the role of immune and inflammatory cells. In addition, recent studies reveal that other cells are also involved. Elucidation of all the types of cells involved is valuable to inform therapeutic interventions for this disease, but most accounts concentrate on cells which are the target of the study and may fail to include other cells. This review therefore aimed at consolidating information on the various cells involved in atherogenesis. Review of contemporary literature was done for cells in the vessel wall and in blood to check for their potential role in atherogenesis. It has been shown that atherogenesis involves all the cells present in the various coats of the vessel wall – endotheliocytes, smooth muscle cells, fibroblasts, stem cells, pericytes, mast cells, dendritic cells, macrophages and immigrant cells usually found in blood, namely monocytes, neutrophils, lymphocytes, platelets and red blood cells. These cells promote atherogenesis by secreting several products which influence inflammation, migration, proliferation and secretory activity of each other in a manner that synergises their activities. Therapeutic interventions should target the various cell types.Key Words: Cells, arterial wall, blood, atherogenesis

Reappraisal of the structure of arterial Tunica adventitia and its involvement in atherosclerosis

Tunica adventitia was previously considered an inert fibrous layer only involved in nutritional and physical support of the arterial wall. Recent studies reveal that it is an important dynamic layer actively involved in the regulation of vascular structure, function, response to injury and disease processes especially atherosclerosis. Many anatomical studies on arteries, however, still make only peripheral reference to it, without elucidating its detailed structure. Knowledge of the latter is important in understanding pathobiology and interventional approaches to atherosclerosis. This review, therefore, aims at consolidating contemporary literature on the structure and clinical significance of the arterial tunica adventitia. Google literature search was done using the key words tunica adventitia combined with: artery, aorta, cells, cell types, collagen, elastic fibres, vasa vasora, lymphatics, nerves, atherosclerosis. There is overwhelming evidence that the tunica adventitia comprises multiple types of collagen and elastic fibres arranged in various directions, a wide variety of cells including fibroblasts, smooth muscle, pericytes,  myofibroblasts, leukocytes, mononuclear phagocytic, defence, mesenchymal stem and mast cells; vasa vasora including  microvasculature, lymphatics and neural elements. The exact cellular, fibre composition and orientation vary between various arteries and regions of the same vessel. Its components are involved in the initiation, progression and complications of  atherosclerosis. In conclusion, the tunica adventitia is an active dynamic layer which, besides mechanical and nutritive  functions; has metabolic, regulatory and defence roles that are critical in arterial homeostasis and  atherosclerosis. Vascular studies should always include detailed analysis of the biology of the tunica adventitia.Key words: Tunica adventitia, cells, fibres, vessels, nerves, atherosclerosi

Variant Anatomy of Intracranial Part of Middle Meningeal Artery in a Kenyan Population

Anatomy of the intracranial part of middle meningeal artery is important during ligation or embolization in epidural haematomas, and in surgical approach to the middle cranial fossa. It shows population variations, but reports from African populations are scanty. This study aimed at describing the variant anatomy of intracranial part of middle meningeal artery in a black Kenyan population. One hundred and sixty middle meningeal arteries and grooves from 80 cadaveric cranial cavities of adult black Kenyans obtained from the Department of Human Anatomy, University of Nairobi Kenya were studied. Measurements taken included length of main trunk, horizontal distance from the branching point to a perpendicular line through midpoint of the zygomatic arch, and a horizontal line from the branching point to a perpendicular line through the tip of the tragus. The branching point of all intracranial divisions was anterior to the tragus and in majority of cases (84.9%) posterior to the mid zygomatic line. The mean distance from the tip of tragus to the point of intracranial division was 30.6 mm, with 57.9% of the cases lying between 20 mm and 35 mm. The average vertical height of the artery from zygomatic point was 10.6 mm, with about two thirds (64.1%) between 3 mm and 22 mm. Majority (51.3%) of the intracranial trunks were between 5 mm and 13 mm long. There were 95.6% and 4.4% bifurcations and trifurcations respectively. The anterior division was deep to the pterion in 66.3%, posterior in 27.5% and anterior in 6.3% of cases. This study revealed that the termination point of the middle meningeal artery in the Kenyan population lies about 14 mm posterior to the mid zygomatic line and about 31 mm from a perpendicular line through the tip of the tragus. It displays variations in stem length, pattern of branching. Only two – thirds of anterior divisions lie deep to the pterion. Neurosurgeons should be aware of these variations during ligation or embolization of the artery and in enlarged middle cranial fossa approach.Keywords: Variations, Landmarks, Middle Meningeal artery, Intracranial, Africa

What is the origin of the labyrinthine artery among black Kenyans?

Origin of labyrinthine artery is important because it influences the presentation of occlusion of anterior inferior cerebellar and basilar arteries. It shows ethnic and geographical variation, but there is no data from black African populations. This study, therefore examined the pattern of origin of labyrinthine artery in adult black Kenyans. Three hundred and fourty six arteries from one hundred and seventy-three formalin fixed brains were examined by dissection at the Department of Human Anatomy University of Nairobi, Kenya. Labyrinthine artery arose from basilar artery in 260 (75.1%); as common trunk with anterior inferior cerebellar artery in 48 (13.9%) and from the latter in 38 (11.0%) of cases. There was no side and gender difference in the pattern of origin. This implies that majority of labyrinthine arteries arise from basilar artery, different from that in oriental, Indo-Asian and Caucasian populations, in which it arises from the anterior inferior cerebellar artery. Preoperative evaluation of basilar artery branching is recommended.Keywords: labyrinthine artery, origin, Kenyan, Basilar, AIC

Histomorphological features of atherosclerosis in the left anterior descending coronary arteries among black Kenyans

The pattern of coronary artery atherosclerosis is valuable in informing mitigation strategies for coronary heart disease. Histomorphological data on this disease among Africans living in Sub Saharan Africa are, however, scarce. The left anterior descending is one of the most commonly afflicted arteries. This study, therefore, examined the left anterior descending artery of 213 black Kenyans [Mean age 36.8 years, range 5 – 82 years] who had died of non cardiovascular causes for features of atherosclerosis. The individuals were divided into male and female, then into 10-yr age groups. Specimens were obtained from the proximal segment of the artery during autopsy at the Department of Human Anatomy University of Nairobi, Kenya. They were processed routinely for paraffin embedding andsectioning. Five micron sections were stained with Haematoxylin/Eosin and Mason’s trichrome and examined with light microscope. Micrographs of representative features were taken using a high resolution digital camera. At least one feature of atherosclerosis was present in 54 (25.4%) of the individuals. The features observed included severe intimal hyperplasia (34; 63%), disintegration of the internal elastic lamina [30; 55.6%]; atherosclerotic plaque (20; 37%), adventitial thicknening (14; 26%) and mural neovascularization (10; 18.5%). The mean age of those with features of atherosclerosis was 38.4 years, range 6 – 62 years with 25 (46.3%) being aged 40 years and below. Of these, the male: female ratio was 1.7:1. In conclusion, features of atherosclerosis are present in over 25% of the population studied. The disease affects young people, including women. Proactive preventive measures including follow – up should commence early, and involve both men and womenKeywords: Atherosclerosis, coronary, young, men, women, Keny