Sternal foramina and variant xiphoid morphology in a Kenyan population.

Sternal foramina may pose a great hazard during sternal puncture, due to inadvertent cardiac or great vessel injury. They can also be misinterpreted as osteolytic lesions in cross-sectional imaging of the sternum. On the other hand, variant xiphoid morphology such as bifid, duplicated, or trifurcated may be mistaken for fractures during imaging. The distribution of these anomalies differs between populations, but data from Africans is scarcely reported. This study therefore aimed to investigate the distribution and frequency of sternal foramina and variant xiphoid morphology in a Kenyan population. Eighty formalin-fixed adult sterna (42 males [M], 38 females [F]) of age range 18-45 years were studied during dissection at the Department of Human Anatomy, University of Nairobi. Soft tissues were removed from the macerated sterna by blunt dissection and foramina recorded in the manubrium, body, and xiphoid process. The xiphisternal ending was classified as single, bifurcated (2 xiphoid processes with a common stem), or duplicated (2 xiphoid processes with separate stems). Results were analysed using SPSS version 17.0. Foramina were present in 11 specimens (13.8%): 7 M, 4 F. The highest frequency was in the sternal body (n = 9), where they predominantly occurred at the 5th intercostal segment. Xiphoid foramina were present in 2 specimens (both males) (2.5%), while manubrial foramen was not encountered. The xiphisternum ended as a single process in 64 cases (34 M, 30 F) (80%). It bifurcated in 10 cases (5 M, 5 F) (12.5%), and duplicated in 6 cases (4 M, 2 F) (7.5%). There were no cases of trifurcation. Sternal foramina in Kenyans vary in distribution and show higher frequency than in other populations. These variations may complicate sternal puncture, and due caution is recommended. The variant xiphisternal morphology may raise alarm for xiphoid fractures and may therefore be considered a differential.

Socio-cultural practices of deciduous canine tooth bud removal among Maasai children.

The removal of teeth amongst the Maasai is a traditional practice as part of an initiation or to make space for feeding in an event of diseases locking the jaw. Removal of deciduous canine tooth buds (DCB) among infants below 2 years has been reported in several studies to be common mainly amongst communities in East Africa, Ethiopia and Sudan. The main reason for the practice revolves around the belief that tooth buds or 'maggots' are false teeth, nylon or worms and are responsible for diarrhoea, vomiting, fever and growth retardation in children, amongst other illnesses. The main objective of this study was to assess the socio-cultural factors which contribute to this practice. The main methods of data collected included Focus Group Discussions (FGD) with mothers of children in that age group and Traditional Birth Attendants (TBA). In-depth interviews (IDI)were conducted with key informants versed with Maasai traditions whereas observations were done within the manyattas where participants live. Proceedings at both the FGD and the IDI were recorded on paper and were analysed thematically. The study showed that the removal of canine tooth buds amongst children that started initially with calves--that diseases that cause diarrhoea in calves were brought about by the canine tooth buds that were turning reddish in colour--is deeply rooted and practised in the community despite sensitisation interventions mounted jointly by the University of Nairobi, Kenya Medical Research Institute and the Kenya Medical Training College, among others. This study discovered that canine tooth buds are associated with bad spirits that cause diarrhoea and vomiting and the belief that removing them is a sure way of providing a cure for all children's ailments.

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.

Perceptions of primary health care with regard to corresponding knowledge, attitude and practices amongst the Kenyan Maasai.

OBJECTIVES: In order to introduce a comprehensive intervention system to improve health, there is need to establish a profile of the Maasais' current knowledge, attitude and practices of predisposing environmental, cultural and other factors which may lead to considerable health risks. DESIGN: A descriptive retrospective cross-sectional study. SETTING: Oletepesi and Elangata Wuas of Kajiando District. SUBJECTS: Maasai community in Oletepesi and Elangata Wuas regions of Kajiado District of Kenya over a period of two years. RESULTS: Previous awareness to primary health care and knowledge has been through education and training by AMREF Nomadic Health Unit. Factors such as limited availability of water, health care delivery and dry arid environment with poor infrastructure as well as some persistent harmful cultural practices predispose the Maasai community to common health problems in children and adults. CONCLUSION: With community participation, there is need for an integrated approach to these health risks. The Ministry of Health together with AMREF have incorporated a comprehensive intervention system to address the commonly occurring diseases such as malaria, diarrhoea and pneumonia and address adults and children problems differently.

Quantitative and somatotopic mapping of neurones in the trigeminal mesencephalic nucleus and ganglion innervating teeth in monkey and baboon.

Neurones of the trigeminal mesencephalic nucleus (Mes V) and ganglion innervating the periodontium of incisor, canine and molar teeth in 10 monkeys and 10 baboons were counted and mapped using the horseradish peroxidase (Hrp), retrograde axonal transport method. Periodontal afferent neurones of all these teeth were well represented in the Mes V, although the incisors had a significantly higher number of labelled neurones than the canines or molars. The primary cell bodies of the periodontal afferents were located mainly in the caudal part of the ipsilateral Mes V from the level of the inferior colliculus to the floor of the fourth ventricle in the pons. The caudal periodontal Mes V neurones may be favourably located to make collateral connections with the trigeminal motor nucleus for jaw reflexes. Incisors and canines had a large and predominantly ipsilateral representation of Hrp-labelled neurones in the ganglion. In contrast, molar representation in the ganglion was sparse and all labelled neurones supplied ipsilateral teeth. The maxillary and mandibular teeth had a somatotopic distribution within the respective maxillary (middle) and mandibular (posterolateral) compartments of the trigeminal ganglion. It is suggested that the anterior teeth with greater connections to the Mes V and the ganglion may impart greater sensory perception and be involved in jaw reflexes to ensure a good occlusal relation during mastication, while the afferent connections of the molars may initiate complex jaw reflexes during the occlusal phase of mastication.

Anterior tooth relations in Kenyan Africans.

Dental plaster casts of 235 Maasai, 116 Kikuyu and 61 Kalenjin children aged 3-16 yr were studied to determine the incidence and magnitude of diastemas, overbite, overjet and anterior open bite. The highest prevalence of diastema was amongst the Maasai (61.3%), of overbite (84%) and overjet (99%) amongst the Kikuyu, and of anterior open bite amongst Kalenjin (24%), with values greater than 0.4 mm up to 11.5 mm. Comparison of the mean values showed that diastema (1.77 mm) and overjet (4.4 mm) were greatest in Maasai, overbite (3.53 mm) in Kalenjin, and anterior open bite (3.50 mm) in Kikuyu. In the total sample, the prevalence and mean of diastema were 49%, 1.68 mm; of overbite 77.4%, 2.96 mm; of overjet 88.6%, 3.83 mm; and of anterior open bite 16.5%, 2.69 mm (with values between 0.4-11.5 mm), while 5.5% had an edge-to-edge bite (-0.5-0.5 mm). The prevalence of diastema decreased whilst its magnitude increased with age. The mean values of overbite and overjet increased, while those for anterior open bite decreased with age. The mean values of diastema, overbite and overjet were greater amongst the females, but the difference was significant only for overjet. The high prevalence and greater values of measurements of anterior tooth relations may be related to variable growth of the bimaxillary dentoalveolar complex and soft tissue influences. This may be important in orthodontic treatment planning, dental prostheses and other clinical dental treatments in Kenyan populations.

Removal of deciduous canine tooth buds in Kenyan rural Maasai.

The removal of deciduous canine tooth buds in early childhood is a practice that has been documented in Kenya and in neighboring countries. This paper describes the occurrence, rationale and method of this practice amongst rural Kenyan Maasai. In a group of 95 children aged between six months and two years, who were examined in 1991/92, 87% were found to have undergone the removal of one or more deciduous canine tooth buds. In an older age group (3-7 years of age), 72% of the 111 children examined exhibited missing mandibular or maxillary deciduous canines. It was found that the actual removal of a deciduous tooth bud is often performed by middle-aged Maasai women who enucleate the developing tooth using a pointed pen-knife. There exists a strong belief among the Maasai that diarrhoea, vomiting and other febrile illnesses of early childhood are caused by the gingival swelling over the canine region, and which is thought to contain 'worms' or 'nylon' teeth. The immediate and long-term hazards of this practice include profuse bleeding, infection and damage to the developing permanent canines. A multi-disciplinary approach involving social anthropologists in addition to dental and medical personnel, is recommend in order to discourage this harmful operation that appears to be on the increase.

The position of mandibular and mental foramina in Kenyan African mandibles.

Analysis of 79 adult African mandibles indicated that 64.6% of the mandibular foramina were located below the level of the posterior extension of the occlusal plane while 30.7% were located along this plane. 56.1% of the mental foramina were located below the second premolar while 31.1% were between the second premolar and first molar. The remainder were located between the premolars. The mental foramen opened posterosuperiorly in 72.5% of the surfaces. Multiple mental foramina were found on 4.5% of the mandibles. While emphasising the importance of palpation prior to administration of mental nerve block, these observations suggest that in case of uneffective mandibular nerve block, for a significant proportion of Kenyan Bantus, attempts to place the anaesthetic solution slightly below the occlusal plane be considered.

Simulation model for dental arch shapes.

OBJECTIVE: To develop a simulation model for dental arch shapes. DESIGN: Analysis of measurements of dental casts to determine a general second degree equation for the dental arches. SETTING: Department of Human Anatomy and School of Computing and Informatics, University of Nairobi. SUBJECTS: The measurement of dental casts, 30 (15M and 15F) each from three Kenyan ethnic groups (Maasai, Kalenjin, Kikuyu), aged 12 years. RESULTS: The arches change their shapes from a parabola to an ellipse, governed by the boundary conditions at the position of the canine tooth, based on the general second degree equation for the conic sections. CONCLUSION: The simulation model graphically confirms the change from parabolic to elliptic shapes of dental arches with boundary conditions at the canine. This could be used to show the changes in dental arches for other ethnic groups.

Clinical report on longitudinal post-eruptive changes in fluorotic enamel observed in 10 cases over a 2 1/2 year period.

The present longitudinal study was conducted on ten children from age 5-6 years to determine the post-eruptive enamel changes of fluorosed permanent incisors. The children were born and reared in an area of Kenya with a water fluoride level of 14-45 parts per million. The incisors were examined and photographed periodically from the time of eruption over a period of 2 1/2 years. It was noted that the fluorosed incisor was intact as it erupted and then it underwent a variety of changes. In some there was mechanical breakdown (pitting) of the chalky white enamel which occurred rapidly initially and then the breakdown slowed down by 2 years. In others, there was smoothening of the pitted enamel resulting in a translucent appearance. Alternatively there was some degree of patchy staining of the enamel without surface breakdown. Much of the cervical 1/3 of the enamel remained intact even in teeth with severe breakdown. In most cases, these changes were bilaterally symmetrical. The possible reasons for these changes are discussed.

Morphometry and variations of bony ponticles of the atlas vertebrae (C1) in kenyans / Morfometría y variaciones de puentes óseos de la vértebra atlas (C1) en kenianos

Atlas bridges, the bony outgrowths over the third segment of the vertebral artery are associated with compression of the artery and nerves. There are limited studies comparing morphometry of the complete atlas bridges and that of the ipsilateral transverse foramen. Bilateral and gender differences in the morphometry of the complete bridges remain relatively unexplored. One hundred and two atlas vertebrae (49 male and 53 female) obtained from the Osteology Department of the National Museums of Kenya were used for this study. The presence of complete posterior atlas bridge (retroarticular canal) and lateral bridge (supratransverse foramen) was noted. Measurements were taken for the diameters of foramina, and the ipsilateral transverse foramina and their areas calculated. Complete posterior bridges occurred in 14.6 percent and 13.6 percent on the right and left sides respectively. The lateral bridge was found in 3.9 percent of the cases on the right side only. The complete posterior bridges had a cross-sectional area of 23.44mm2 on the right and 24.98mm2 on the left side. The lateral bridges had a mean cross-sectional area of 27.30mm2. The right and left transverse foramina had mean crosssectional area of 36.30mm2 and 37.20mm2 respectively, which was significantly larger than that of the ipsilateral complete and posterior bridges. The smaller dimensions of the complete atlas bridges compared to the ipsilateral transverse foramen suggest that they may predispose to vertebrobasilar insufficiency, Barre-Lieou and cervicogenic syndromes due to compression of the contents in the foramina.

Puentes del atlas, sobrecrecimientos óseos en el tercer segmento de la arteria vertebral se asocian con la compresión de la arteria y los nervios. Hay pocos estudios que comparan la morfometría de los puentes completos del atlas y el foramen transversal ipsilateral. Diferencias bilaterales y de género en la morfometría de los puentes completos permanecen relativamente inexplorados. Ciento dos vértebras atlas (49 hombres y 53 mujeres) obtenidos del Departamento de Osteología 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 diámetros del foramen y los forámenes transversos ipsilaterales, y se calcularon sus áreas. Puentes completos posteriores se observaron en el 14,6 por ciento y 13,6 por ciento de los lados derecho e izquierdo, respectivamente. El puente lateral se encontró en el 3,9 por ciento de los casos en el lado derecho solamente. Los puentes completos posteriores tuvieron un área transversal de 23,44mm2 en el lado derecho y 24,98mm2 en el lado izquierdo. Los puentes laterales tuvieron un área media de sección transversal de 27,30mm2. En los lados derecho e izquierdo se encontrron forámenes transversos con un área promedio de sección transversal de 36,30mm2 y 37,20mm2 respectivamente, lo que fue significativamente mayor que el de los puentes completos ipsilaterales y posteriores. Las dimensiones más pequeñas de los puentes atlas completos en comparación con los forámenes transversos ipsilaterales sugieren que pueden predisponer a la insuficiencia vertebrobasilar, síndromes de Barre-Lieou y cervical debido a la compresión de los contenidos en los forámenes.

Incidence of Carabelli's trait in Kenyan Africans and Asians.

Examination for incidence of Carabelli's trait was done on 1267 Africans and 781 Asian school children, 298 dental plaster casts and 248 skulls of Africans. The African sample is composed of 80% Bantu, 20% Nilote, and Nilo-Hamitic people. When observed intraorally, the trait is present in 31-35% of Africans and 26-27% of Asians. In the dental casts and skull sample of Africans, the trait is present as pit in 23-28%, groove in 20%, and as tubercle and cusp in 22%. The total trait frequency in Africans is 68%.

Biometric analysis of the mandibles of Papio anubis and Cercopithecus aethiops.

Six biometric measurements were recorded from dry mandibles of 53 Papio anubis and 84 Cercopithecus aethiops: intercondylar width, intercoronoid width, intermolar width (IMW), mesiodistal width of the condyles, height of the occlusal table and anteroposterior length of the chewing surface from P4 to M3 (CL). The mean values and correlation matrices of these variables show that, despite the difference in size, the overall shape of the mandible in male and female is similar within species. The principal component analysis shows that in P. anubis the six variables contribute almost equally to the first component (75% of total variance), suggesting that the large mandible may be force related because of the greater mechanical forces required for chewing certain foods. In C. aethiops, the contribution of IMW and CL is less in the first component (52.7% of total variance), suggesting that the biochemical forces of mastication are more complex to adapt the mandible to a shorter muzzle and a particular diet.

The third permanent molar eruption in Kenyan Africans and Asians.

Data on third permanent molar eruption was obtained from a cross-sectional study of 1343 African and 1092 Asian students aged 13-23 years attending various schools in Nairobi and the University of Nairobi, Kenya. Africans are significantly ahead of the Asians in third molar emergence. As seen from the median age of eruption, in Africans mandibular molars emerge at 17.6-18.3 years followed by the maxillary at 18.5-18.9 years, while in the Asians mandibular molars emerge at 19.9-20.3 years and maxillary at 20.7-21.0 years. African females appear to be earlier than the males in median age of eruption by 0.3-0.4 years, while the Asian females tend to be later than the males by about 0.3 years, but these differences are not significant. Third molar emergence starts earlier in Africans at 13 years of age, and by 18.5 years 50% of Africans have all four molars present. In the Asians, third molar emergence begins at about 15 years and by 21.5 years 50% have all four molars present.

Biometric analysis of the dental casts of Maasai following traditional extraction of mandibular permanent central incisors and of Kikuyu children.

Dental plaster casts of 93 Maasai and 79 Kikuyu children age 12-15 years were analysed. Four biometric measurements were taken of the maxillary and mandibular casts: intercanine distance (C-C), inter-molar distance (M-M), canine arch circumference (C-C ACirc.), and molar arch circumference (M-M ACirc.). Incisor space (IS) was also measured in the mandibular casts. The mean values of all measurements except (M-M) in the mandibular casts were significantly reduced in the Maasai who had permanent central incisors extracted compared to the non-extracted Maasai and the Kikuyu. The mean incisor space in the Maasai with extractions was 6.3 mm compared to 11.7 mm in the non-extracted Maasai group. The extent of reduction of IS, C-C, C-C ACirc. and M-M ACirc. following extractions of the incisors may depend on the mesial drift of lateral incisors, jaw growth and soft tissue influence. The position of the tongue and occlusal relationship of the molars may prevent bucco-lingual movements maintaining a constant M-M. There was no significant difference in the mandibular cast dimensions of the non-extracted Maasai and the Kikuyu. Analysis of the maxillary cast dimensions of the Maasai with extraction, non-extracted Maasai and Kikuyu showed no significant differences suggesting that the extraction of mandibular incisors has no effect on maxillary arch dimensions. The variability in growth of the dento-alveolar complex itself may explain why the dental arch dimensions are similar in the Maasai and Kikuyu despite ethnic differences. There was no significant difference between the male and female dental arch dimensions.

Palatal analysis and osteology of the hard palate of the Kenyan African skulls.

One hundred twenty-five dry skulls from Kenya that consisted of about 90% Bantu individuals were examined to obtain data on the gross anatomy of the hard palate. The palatine index showed that 43.2% of the total sample of skulls has narrow (leptostaphyline), 23.7% intermediate (mesostaphyline), and 33.1% wide (brachystaphyline) palates. The palatine height index showed that 40% skulls had low (chamestaphyline), 57% intermediate (orthostaphyline), and 3.0% deep (hypsistaphyline) palates. Mean palatal length, breadth, and height for the total sample was 4.92 cm, 4.02 cm, and 1.22 cm, respectively. The incisive foramen and canal was cone shaped in 80% where the diameter of the foramen was less than 0.4 cm, while it was cylindrical in 20% where the diameter was greater than 0.4 cm. Forty-nine per cent of the skulls had two-five lesser palatine foramina present. The greater palatine foramen was found to lie at the level of the third molar in 76%, intermediate between second and third molars in 13.6%, and opposite the second molar in 10.4%. The greater palatine foramen opened antero-medially in 74% and perpendicularly in 26% of the palates. Extensive longitudinal palatal grooves were found bilaterally in all the palates, 70% showed divisions of the grooves, 63.2% had crests along the border of the grooves, and 19.2% had bridges in the posterior part of the groove near the opening of the greater palatine foramen. The incidence of palatine torus was 4.8%. The incisive suture was present in 6.4% of the adult palates.

Analysis of dental casts of 6-8- and 12-year-old Kenyan children.

Dental plaster casts of 97 6-8-year-old and 173 12-year-old Maasai, Kikuyu, and Kalenjin children were studied. The Kikuyu are Bantu, while Maasai and Kalenjin are Nilo-Hamitic subjects. The variables measured were palatal depth (PD) and length (PL); maxillary and mandibular anterior arc circumferences (AC1) and (AC2), respectively; posterior arc circumferences (PC1) and (PC2), inter-canine (CC1), and (CC2); inter-molar (MM1) and (MM2) distances, and mandibular length (ML). The data were analysed using SPSS package. The mean values of all the variables were generally higher in the males compared with the females and significant sex differences in the means (P < 0.01) were found in AC1, PC1, PC2, CC1, CC2, MM1, and MM2 in the 12-year-old subjects. The means of all variables, except PL, ML, PC2, and CC2, increased from 6 to 12 years of age and significant differences in the means for age were found in ML, AC1, PC2, PD, MM1, MM2, and CC1. Mean maxillary inter-molar distance increased with age by 0.17-0.34 mm in the three groups. Mean values of mandibular variables were highest in the Kikuyu, while maxillary variables were highest in the Maasai. The Maasai casts showed a marked decrease in CC2, PC2, AC2, and ML compared with the Kikuyu and Kalenjin. Ethnic and sex differences in the dental arches may be masked by anterior tooth positions that are influenced by the dento-alveolar complex and soft tissues. Corresponding mandibular and maxillary variables were strongly correlated and anterior and posterior arc circumferences were correlated with inter-canine and intermolar distances. Details of the norms for dental arch dimensions and changes with age may allow for appropriate assessment of dental occlusion and treatment planning for Kenyan children.

Ages of eruption of the permanent teeth in Kenyan African and asian children.

Mean ages of eruption of the permanent teeth (except 3rd molars) in African and Asian children were derived from a cross-sectional study of 2847 children aged 4-14 years, in selected nursery and primary schools in Nairobi, Kenya. Except for the premolars, the mandibular teeth erupted earlier than the maxillary ones in both races. The mandibular incisors and canines erupted earlier by 0.9-1.1 yr in Africans and 0.6-0.8 yr in Asians, and the molar by 0.2-0.4 yr in both races. The maxillary premolars were ahead of mandibular premolars by 0.1-0.2 yr in both races. The females were ahead of males in both races. Compared with the Asians, the African permanent teeth erupted earlier by 0.2-0.7 yr. The most frequent order of eruption in Africans is Mand I1, Mand M1, Max M1, Mand I2, and Max I1 between 5-7 years, while in the Asians the most frequent order is Mand M1, Mand I1, or Max M1, Max I1 and Mand I2 between 6-8 years. The incidence of Cusp of Carabelli in Africans and Asians is about 19-25%.