Cerebral Artery Hypoplasia in a Select Adult Kenyan Population.

Background Hypoplasia of cerebral arteries predisposes to stroke and cerebral aneurysms which have an increased incidence in sub-Saharan Africa. The frequency and pattern of cerebral artery hypoplasia, however, shows population variations, and data from the African population remain scanty. Objectives This study aimed to determine the percentage of hypoplasia in the anterior, middle, and posterior cerebral, anterior and posterior communicating, basilar, and vertebral arteries. Materials and Methods Sections of the basilar, vertebral, posterior, and anterior communicating arteries and anterior, middle, and posterior cerebral arteries were taken, processed for histology, and examined with a light microscope at ×40. The images of the vessels were taken by a photomicroscope and circumference analyzed with the aid of Scion image analyzer. The average diameter of 10 sections was taken to be the diameter of the artery in analysis. Hypoplasia was then defined as internal diameter ≤1 mm. Photographs of representative samples of asymmetry were taken, data were analyzed using SPSS, and gender differences were analyzed using the Student's test. Results were presented in tables. Results Two hundred and eighteen formalin-fixed brains of adult Kenyans at the Department of Human Anatomy, University of Nairobi, were studied. Of the 218, 48 brains (22%) did not have vessels with any form of hypoplasia while 170 (78%) did have vessels. Of these, anterior circulation hypoplasia (anterior cerebral artery and posterior communicating artery) was seen in 100 brains (46%) and posterior circulation hypoplasia (middle and posterior cerebral, basilar, and vertebral arteries) in 69 brains (32%). Conclusion Cerebral arterial hypoplasia is frequent in the select adult Kenyan population.

Morphology and morphometry of the distal articular surface of lunate bone in a Kenyan population / Morfología y morfometría de la superficie articular distal del hueso semilunar en una población de Kenia

The morphology and morphometry of the distal articular surface of the lunate exhibits inter-population variations. They are of clinical importance to hand surgeons due to their influence on the occurrence of proximal pole arthrosis which is a cause of ulnar-side wrist pain. The objective of the study was to determine the morphology and morphometry of the distal articular surface of the lunate bone in an adult Kenyan population. A descriptive cross-sectional study at the Department of Human Anatomy, University of Nairobi. Fifty-six human hands obtained for routine dissection were used. The morphology of the distal articular surface of the lunate was classified as either Type I or Type II depending on the absence or presence of a medial facet for articulation with the hamate respectively. The width of the wrists and of the medial facet in Type II lunates was measured with SOMETTM CN-25 1234 vernier calipers (accurate to 1mm). Photomacrographs of representative lunate were taken. Data were analyzed using SPSS version 17.0. The Pearson correlation test was used to check for any correlations. Type II lunate morphology was more common with a prevalence of 34 (61 %) while 19 (34 %) were Type I. The mean width of wrists with Type I lunate was 41.1±2.8 mm while those with Type II had a mean width of 46.1±4.3 mm. The mean width of the medial facet in lunate type II was 4.4±1.4 mm. Lunotriquetral fusion was demonstrated in 3 (5 %) wrists. Prevalence of Type II lunate was higher than Type I. Wrists with a Type II lunate were wider than those with Type I. There was no correlation between the width of the wrist and the width of the medial facet of the lunate.

La morfología y morfometría de la superficie articular distal del hueso semilunar muestra variaciones entre la población. Es de importancia clínica para los cirujanos de mano debido a su influencia en la incidencia de la artrosis del polo proximal, que causa dolor ulnar en la muñeca. El objetivo fue determinar la morfología y morfometría de la superficie articular del hueso semilunar en una población adulta de Kenia. Estudio descriptivo de corte transversal, realizado en el Departamento de Anatomía Humana de la Universidad de Nairobi. Se utilizaron 56 manos humanas que fueron sometidas a disección de rutina. La morfología de la superficie articular distal del hueso semilunar se clasificó en Tipo I o Tipo II en función de la ausencia o presencia de una faceta medial de la articulación. El ancho de las muñecas y de la faceta medial en el Tipo II se midió con el caliper SOMETTM CN-25 1234 (precisión de 1 mm). Se tomaron macrofotografías representativas del hueso semilunar. Los datos fueron analizados con el programa SPSS versión 17.0. Se utilizó la prueba de correlación de Pearson. La morfología del hueso semilunar Tipo II fue más frecuente con una prevalencia de 34 casos (61 %), mientras que 19 casos (34 %) eran de Tipo I. El ancho promedio de las muñecas del hueso semilunar Tipo I fue de 41,1±2,8 mm, mientras que las de Tipo II fue de 46,1±4,3 mm. El ancho promedio de la cara medial del hueso semilunar Tipo II fue de 4,4±1,4 mm. Se demostró fusión semilunar-piramidal en 3 casos (5 %). La prevalencia del hueso semilunar Tipo II fue mayor que la del hueso semilunar Tipo I. Las muñecas que presentaban hueso semilunar Tipo II fueron más anchas que las de Tipo I. No hubo correlación entre el ancho de la muñeca y el ancho de la faceta medial del hueso semilunar.

Anatomy and prevalence of atlas vertebrae bridges in a Kenyan population: An osteological study.

Atlas bridges are bony outgrowths over the third segment of the vertebral artery. They may exist as incipient, incomplete, or complete bridges, converting the groove into a deep sulcus, incomplete, or complete foramen respectively. These bridges and their associated foramina display bilateral and sex differences in their prevalence and type. Occurrence of these bridges may predispose to vertebrobasilar insufficiency and Barre-Lieou syndrome. The coexistence of lateral and posterior bridges as well as side predilection is not clear in either sex. Their relative occurrence may also point to some evolutionary patterns. We studied the prevalence, side predilection, coexistence, and anatomical features of atlas bridges using 102 dry atlases (49 males and 53 females) obtained from the osteology department of the National Museums of Kenya. Complete posterior bridges occurred in 14.7% and 13.7% on the right and left sides, respectively. A lateral bridge was found in 3.9% of cases on the right side only. There was positive correlation in the coexistence of the bridges. A retrotransverse foramen was found in 13% of cases. This study has found that posterior and lateral atlas bridges occur in association especially on the right side. Complete bridges were more prevalent in females and were more often present on the right side. This pattern seems to mirror the sexual predilection of vertebral artery compression syndromes. Gender roles may have an influence on the occurrence of these bridges and therefore the syndromes as well.

Variant anatomy of the cystic artery in adult Kenyans.

Knowledge of the variant vascular anatomy of the subhepatic region is important for hepatobiliary surgeons in limiting operative complications due to unexpected bleeding. The pattern of arterial blood supply of 102 gallbladders was studied by gross dissection. The cystic artery originated from the right hepatic artery in 92.2% of cases. The rest were aberrant and originated from the proper hepatic artery. Accessory arteries were observed to originate from proper hepatic artery (n = 5), left hepatic artery (n = 2), and right hepatic artery (n = 1). Most of the arteries approached the gallbladder in relation to the common hepatic duct (anterior 45.1%, posterior, 46.1%). The other vessels passed anterior to common bile duct (2.9%), posterior to common bile duct (3.9%), or were given off in Calot's triangle. Cystic arteries in this data set show wide variations in terms of relationship to the duct systems. In about one tenth of patients, an accessory cystic artery may need to be ligated or clipped during cholecystectomy.