Paul Odula

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. Clin. Anat. 23:649–653, 2010.

Anatomic position of the asterion in Kenyans for posterolateral surgical approaches to cranial cavity.

The asterion, defined as the junction between lambdoid, parietomastoid, and occipitomastoid sutures, has been used as a landmark in posterolateral approaches to the posterior fossa. Its reliability however has been put into question due to its population‐specific variability in position, using external palpable landmarks and its relation to the transverse–sigmoid sinus complex. This study aimed at determining the anatomic position of the asterion in a Kenyan population. Measurements from the asterion to the root of zygoma and the tip of mastoid process, respectively were taken on both left and right sides of 90 (51 male, 39 female) human skulls. The relation of the asterion to the transverse–sigmoid sinus junction was also determined. The distances on the right and left sides from the asterion to the root of the zygoma were 58.85 ± 2.50 mm and 58.44 ± 2.12 mm, respectively. The asterion was 47.89 ± 3.72 mm above the tip of mastoid process on the right side and 47.62 ± 2.87 mm on the left side. This point was significantly higher in males (48.36 ± 2.72 mm) than in females (46.62 ± 3.37 mm) with a P‐value of 0.041. Regarding its position from the transverse–sigmoid sinus junction, it was at the junction in 72 cases, below it in 17 cases (average 3.68 mm) and only one case had the asterion above this junction (2.57 mm). The asterion therefore can reliably be ascertained using the parameters from the root of the zygoma and the tip of the mastoid process. The safest approach would be posteroinferior to the asterion so as to avoid lacerating the transverse–sigmoid sinus complex. Clin. Anat. 23:30–33, 2010.

Locating the Arcuate Line of Douglas: Is It of Surgical Relevance?

Ventral hernia formation is a common complication of rectus abdominis musculocutaneous flap harvest. The site and extent of harvest of the flap are known contributing factors. Therefore, an accurate location of the arcuate line of Douglas, which marks the lower extent of the posterior wall of the rectus sheath, may be relevant before harvesting the flap. This study is aimed at determining the position of the arcuate line in relation to anatomical landmarks of the anterior abdominal wall. Arcuate lines were examined in 80 (44 male, 36 female) subjects, aged between 18 and 70 years, during autopsies and dissection. The position of the arcuate line was determined in relation to the umbilicus, pubic symphysis, and intersections of rectus abdominis muscle. Sixty four (80.4%) cases had the arcuate line. In most cases (52), this line was located in the upper half of a line between the umbilicus and the pubic symphysis. Most males (93%) had the arcuate line, while more than a third of females did not have it. In all these cases, the line occurred bilaterally as a single arcade, constantly at the most distal intersection of the rectus abdominis muscle. Consequently, the arcuate line is most reliably marked superficially by the distal tendinous intersection of the rectus abdominis muscle. Harvesting of the muscle cranial to this point will minimize defects in the anterior abdominal wall that may lead to hernia formation. Clin. Anat. 23:84–86, 2010.

Anatomic Position of the Pterion among Kenyans for Lateral Skull Approaches

La pterion es un punto de confluencia sutural visto en la norma lateral del craneo, donde se unen los huesos frontal, parietal, temporal y esfenoides. La posicion del pterion exhibe variaciones en la poblacion. La ubicacion de este punto es importante en abordajes quirurgicos a las fosas craneales anterior y la media. Mediciones especificas se han realizado en ambos lados de 90 craneos humanos Kenyanos (51 varones, 39 mujeres). Las distancias desde el centro de pterion a la sutura frontocigomatica fue de 38,88+3,49 mm en el lado derecho y 38,24+3,47 mm en el lado izquierdo. El pterion fue ubicado 30,35+3,40 mm y 30,34+4,34 mm por encima del punto medio del arco cigomatico en los lados derecho e izquierdo, respectivamente. Los hombres presentaron un pterion estadisticamente significativo superior en comparacion con las mujeres, siendo de 39,31+3,28 mm y 37,35+2,97 mm por encima del punto medio del cigoma, respectivamente. La sutura frontocigomatica y el punto medio del cigoma pueden ser utilizados como referencia fiables para localizar a el pterion. Esta informacion puede ser util en la planificacion previa a la cirugia, sobre todo cuando los equipos dispositivos de neuronavegacion son escasos.

Child maltreatment at a violence recovery centre in Kenya

SUMMARY Kenyan media reports indicate escalating levels of child maltreatment, but the characteristics of the offence are undefined. At the Gender and Violence recovery Center of the Nairobi Womens Hospital, we analysed 342 consecutive children for age, gender, perpetrator characteristics, time and scene of assault and the nature of injuries between February 2003 and April 2004. The children comprised 43.5% of all assault survivors. The mean age was 10.0 years and about 20% of the children were ≤5 years. Most (71.5%) of the child sexual abuse (CSA) was perpetrated by people known to the victim. Intra-family CSA (incest) was highest among the one to five year olds. The proportion of assaults committed against boys reduced with the age of the child. Older children were more likely to be assaulted later in the day and by multiple perpetrators. Most recorded injuries were perineal. The majority of children are assaulted by people they had trusted. The epidemiological correlates of maltreatment differ for younger and older children. More effort is needed to further characterize child violence and protect this vulnerable section of the population.

Morphometry and Variations of Bony Ponticles of the Atlas Vertebrae (C1) in Kenyans

Puentes del atlas, sobrecrecimientos oseos en el tercer segmento de la arteria vertebral se asocian con la compresion de la arteria y los nervios. Hay pocos estudios que comparan la morfometria de los puentes completos del atlas y el foramen transversal ipsilateral. Diferencias bilaterales y de genero en la morfometria de los puentes completos permanecen relativamente inexplorados. Ciento dos vertebras atlas (49 hombres y 53 mujeres) obtenidos del Departamento de Osteologia de los Museos Nacionales de Kenya se utilizaron para este estudio. Fueron identificados la presencia de puentes completos posteriores del atlas (canal retroarticular) y puentes laterales (foramen supratransverso). Se realizaron las mediciones de los diametros del foramen y los foramenes transversos ipsilaterales, y se calcularon sus areas. Puentes completos posteriores se observaron en el 14,6% y 13,6% de los lados derecho e izquierdo, respectivamente. El puente lateral se encontro en el 3,9% de los casos en el lado derecho solamente. Los puentes completos posteriores tuvieron un area transversal de 23,44mm2 en el lado derecho y 24,98mm2 en el lado izquierdo. Los puentes laterales tuvieron un area media de seccion transversal de 27,30mm2. En los lados derecho e izquierdo se encontrron foramenes transversos con un area promedio de seccion transversal de 36,30mm2 y 37,20mm2 respectivamente, lo que fue significativamente mayor que el de los puentes completos ipsilaterales y posteriores. Las dimensiones mas pequenas de los puentes atlas completos en comparacion con los foramenes transversos ipsilaterales sugieren que pueden predisponer a la insuficiencia vertebrobasilar, sindromes de Barre-Lieou y cervical debido a la compresion de los contenidos en los foramenes.

Variations in the pattern of formation of the abdominis rectus muscle sheath among Kenyans

El patron de formacion de la vaina del musculo recto abdominal humano muestra variaciones, no esta claro si estas variaciones son poblacion-especificas. Este estudio tiene como objetivo describir el patron de formacion de la vaina del musculo recto del abdomen en una poblacion seleccionada de Kenia. La formacion de la vaina del musculo recto del abdomen se analizo en 80 sujetos (47 hombres, 33 mujeres) durante autopsias y diseccion de cadaveres. La pared anterior de la vaina del musculo recto en todos los casos era aponeurotica y firmemente unida al musculo recto abdominal. La pared posterior de la vaina del musculo recto era aponeurotica en 71 (88,5%) casos, las paredes restantes eran musculoaponeuroticas y solo se observaron en varones. En todos los casos, la aponeurosis del musculo oblicuo interno del abdomen se dividio en dos laminas, una lamina profunda que se fusionaba con la aponeurosis del musculo transverso del abdomen en el borde lateral del musculo recto del abdomen y una lamina superficial que se fusionaba con la aponeurosis del musculo oblicuo externo del abdomen a mitad del recorrido entre los bordes medial y lateral del musculo recto del abdomen. El patron de formacion de la vaina del musculo recto del abdomen, entre los kenianos muestra algunas variaciones que no han sido reportadas en trabajos anteriores. El conocimiento de estas variaciones es importante en cirugia ya que esta vaina es seccionada en abordajes abdominales.

Course of the hepatic inferior vena cava in a Kenyan population.

The course of the hepatic inferior vena cava (HIVC) has a wide range of variations which are relevant in hepato‐vascular surgery and liver transplantation. Eighty livers were studied for hepatic course and axial orientation of the HIVC. The HIVC was found to run in an incomplete tunnel in 43.8% of the cases (n = 35), complete tunnel in 32.5% of the cases (n = 26) while in the rest, it was contained in a shallow groove on the retrohepatic surface. It assumed an oblique course in relation to the longitudinal axis of the liver in 60% of the cases (n = 48). The findings of this study vary to a wide range from those reported previously, and call for extra caution during surgical operations involving the HIVC region. Clin. Anat. 22:610–613, 2009.

Sex Variation in Occurrence of Myocardium in Human Mitral Valve Cusps

Las cuspides de la valva mitral estan constituidas principalmente por tejido conectivo y miocardio. Se ha demostrado que las fibras del tejido conectivo de las cuspides presentan diferencias en la organizacion segun sexo. El prolapso mitral, una enfermedad atribuida a defectos en las cuspides es mas frecuente en las mujeres. Las variaciones de sexo en el miocardio valvular sin embargo aun no se han estudiado. Las posibles variaciones en su organizacion puede mejorar la comprension de las diferencias de sexo en la prevalencia de prolapso mitral. El objetivo de este estudio fue determinar las variaciones anatomicas del miocardio valvar mitral por sexo, por medio un estudio comparativo de corte transversal. Un total de 48 los especimenes de corazon adulto (se utilizaron 27 hombres y 21 mujeres), obtenidos durante autopsias en la ciudad de Nairobi y desde el deposito de cadaveres Chiromo, despues de la aprobacion etica. Las cuspides valvares fueron extraidas. Fueron realizadas secciones de cuatro milimetros en el parte mas ancha de las cuspides anteriores y posteriores. Estas fueron procesadas por inclusion en parafina, corte y tincion con tricromico de Masson y fucsina-resorcina de Weigert con contraste Van de Gieson, para demostrar la presencia de musculo cardiaco, fibras colagenas y elasticas. Tanto cuspides anteriores como posteriores demostraron tres laminas histologicas, es decir, atrial, fibrosa y ventricular. Solo en la lamina atrial se observo musculo cardiaco. Esta lamina en los hombres se caracterizo por una banda de orientacion transversa de miocardio subendotelial, mientras que en las mujeres se observaron fibras longitudinales 0elasticas compactas, pero no musculo. La presencia de musculo cardiaco en la lamina atrial puede servir relativamente como proteccion contra el prolapso de la valvula mitral en los varones en comparacion con las mujeres.

Effect of Monocular Deprivation on Rabbit Neural Retinal Cell Densities

Purpose: To describe the effect of monocular deprivation on densities of neural retinal cells in rabbits. Methods: Thirty rabbits, comprised of 18 subject and 12 control animals, were included and monocular deprivation was achieved through unilateral lid suturing in all subject animals. The rabbits were observed for three weeks. At the end of each week, 6 experimental and 3 control animals were euthanized, their retinas was harvested and processed for light microscopy. Photomicrographs of the retina were taken and imported into FIJI software for analysis. Results: Neural retinal cell densities of deprived eyes were reduced along with increasing period of deprivation. The percentage of reductions were 60.9% (P < 0.001), 41.6% (P = 0.003), and 18.9% (P = 0.326) for ganglion, inner nuclear, and outer nuclear cells, respectively. In non-deprived eyes, cell densities in contrast were increased by 116% (P < 0.001), 52% (P < 0.001) and 59.6% (P < 0.001) in ganglion, inner nuclear, and outer nuclear cells, respectively. Conclusion: In this rabbit model, monocular deprivation resulted in activity-dependent changes in cell densities of the neural retina in favour of the non-deprived eye along with reduced cell densities in the deprived eye.