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A rare case of sagittal dislocation of the hypoplastic right semi-posterior arch of the atlas, complicating a cervical trauma, is described. The authors specify its radiographic and CT appearance. This is a congenital abnormality discovered accidentally, for which no specific surgical treatment was implemented.
BACKGROUND AND DESIGN: Epiluminescence microscopy (ELM) is a clinical technique that permits in vivo visual inspection of pigmented anatomic structures of the epidermis, dermoepidermal junction, and papillary dermis. A protocol is proposed for systematic visual inspection of pigmented lesions. Seventy pigmented lesions were imaged with a digital ELM camera system. Images were visually inspected for eight "global" ELM features, 23 "local" ELM features, and 18 network features. An atlas of the most clinically significant ELM features is presented with pilot estimates of their sensitivity and specificity for detecting melanoma. RESULTS: Preliminary data suggest that ELM features that may be most specific for melanoma include multicomponent pattern, nodular pattern, pseudopods, radial streaming, blue-gray areas, whitish veil (milky way), and sharp network margins. Epiluminescence microscopic features that may be most sensitive for melanoma include pigment dots, peripheral erythema, peripheral dark network patches, marked mean network irregularity, network line thickness variability, radial streaming, blue-gray areas, and whitish veil (milky way). Epiluminescence microscopic features that may be most sensitive for severe melanocyte atypia include pigment dots, peripheral erythema, hypopigmented network patches, peripheral dark network patches, marked mean network irregularity, and focal absence of network. In addition, features that may have a very high specificity for benign lesions include saccular pattern (suggests hemangioma), globular pattern (suggests a compound or dermal nevus), and multiple comedolike openings (suggests seborrheic keratosis). CONCLUSIONS: Features most sensitive for severe atypia and melanoma could form the basis for a screening test for considering biopsy. Features most specific for melanoma then could be applied to further triage management of pigmented lesions that meet initial screening criteria. In addition, features with very high specificity for benign lesions may help develop ELM criteria to avoid unnecessary surgery.
An unusual case of rotary dislocation of atlas upon axis is presented. Included in the article are associated causes, the articulations of the area, a case history and radiological assessment. The article ends with the radiographic and technical factors involved.
One case of fracture of the atlas associated with rupture of the transverse ligament and three cases of atlantal fracture with associated fractures of the odontoid process are reported. In such cases, halo immobilization is recommended until the atlantal fracture has healed, followed by atlanto-axial fusion for instability of the cervical spine.
In some patients, suspected fractures of the cranial part of the cervical spine are difficult to diagnose properly without the use of computed tomography or MT. In addition to imaging and positioning problems, the possibility of anomalies of the atlas vertebra may complicate the diagnostic considerations. Proper knowledge of such anomalies may facilitate the diagnostic procedures. The diagnostic problems are discussed, and are illustrated through two patients recently examined in our department.
On the basis of three operated patients a posterior, lateral and antero-lateral approaches to the atlas and axis are presented. The type of approach depends on location and extent of a lesion in the vertebra.
We report five cases of acute neck pain with fever in patients with diffuse articular chondrocalcinosis and computed tomography evidence of calcification of the transverse ligament of the atlas. A review of the relevant literature illustrated the high frequency of this condition, the variability of clinical presentations ranging from episodes of acute neck pain with fever to compression of the proximal spinal cord, the value of computed tomography for determining the site of the calcific deposits and assessing the lesions, and the possibility of deposition of both calcium pyrophosphate dihydrate and hydroxyapatite crystals in the same patient.
The adult Xenopus presents the unique capability to smell odors both in water and air thanks to two different olfactory pathways. Nevertheless, the tadpole can initially perceive only water-borne odorants, as the olfactory receptor neurons (ORN) that will detect air-borne odorants develop later. Such a phenomenon requires major reorganization processes. Here we focused on the precise description of the neuroanatomical modifications occurring in the olfactory bulb (OB) of the tadpole throughout metamorphosis. Using both carbocyanine dyes and lectin staining, we investigated the evolution of ORN projection patterns into the OB from Stages 47 to 66, thus covering the period of time when all the modifications take place. Although our results confirm previous works (Reiss and Burd [1997] Semin Cell Dev Biol 8:171-179), we showed for the first time that the main olfactory bulb (MOB) is subdivided into seven zones at Stage 47 plus the accessory olfactory bulb (AOB). These seven zones receive fibers dedicated to aquatic olfaction ("aquatic fibers") and are conserved until Stage 66. At Stage 48 the first fibers dedicated to the aerial olfaction constitute a new dorsomedial zone that grows steadily, pushing the seven original zones ventrolaterally. Only the part of the OB receiving aquatic fibers is fragmented, reminiscent of the organization described in fish. This raises the question of whether such an organization in zones constitutes a plesiomorphy or is linked to aquatic olfaction. We generated a 3D atlas at several stages which are representative of the reorganization process. This will be a useful tool for future studies of development and function.
The present paper provides a brainstem atlas showing the distribution of catecholaminergic cells and processes, as well as serotonergic perikarya, in the pygmy marmoset. The findings revealed by the Falck and Hillarp histofluorescence method conform in essential details to what has been described in rodents. These and other comparative data indicate that a prototypical pattern of organization of aminergic systems has been retained in the evolution of primates.
The present paper provides an atlas showing the distribution of melanin-containing nerve cells in the human brainstem. It was found that neuro-melanin, which can be viewed as a waste product of catecholamine metabolism, is suitable as a natural marker for catecholaminergic neurons in the medulla oblongata, pons, and te mesencephalon of the adult human brain. Within these areas of the brain, there is a striking similarity between the location of melanin and the catecholamine cell bodies described in various animals and in human fetuses, whereas no melanin was found in the diencephalic dopaminergic cell groups. Cell counts from the center of each area showed that the mean density of melanin-containing perikarya varied considerably between the different areas.
Outline drawings of representative frontal sections of the Macaca fascicularis brain are presented in stereotaxic coordinates. The levels extend from the rostral tip of the neostriatum to the posterior end of the deep cerebellar nuclei. The illustrations are based on the photographs of unstained frozen sections of three formalin-fixed brains in which stainless steel needles were inserted to mark the horizontal zero and several anteroposterior positions. The sections were not stained in order to prevent shrinkage. Stereotaxic measurements were taken in situ of the highest points on the cortical surface, the position of the central and lunate sulcus, and of certain landmarks at the base of the cranium in a large number of monkeys. These data along with brain dimensions and the weight of animals are displayed in tables to indicate individual variations and to aid investigators in determining the best stereotaxic coordinates for a given structure. It is recommended that the cortical point of entry for an electrode or needle be routinely noted and be compared to the parameters in the atlas to compensate for deviations in the horizontal plane.
The localisation of the primary visual centres in the chick mesencephalon and diencephalon was determined by autoradiographic anterograde transport and degeneration techniques. Strong visual projections were found in the tectum, lateral anterior thalamic nucleus, lateroventral geniculate nucleus, superficial synencephalic nucleus, external nucleus, ectomammillary nucleus, tectal grey, dorsolateral anterior thalamus, rostrolateral part, and the pretectal optic area. Weaker retinal projections were found in the ventrolateral thalamus, two subregions of the dorsolateral anterior thalamus, lateral part, diffuse pretectal nucleus, dorsolateral anterior thalamus, magnocellular part, and the hypothalamus. An atlas of the retinal projections was constructed from sections.
The topographic distribution of central cholinergic and catecholaminergic neurons has been investigated in the baboon (Papio papio). The perikarya were mapped on an atlas through the brain and spinal cord employing sections processed for acetylcholinesterase (AChE) pharmacohistochemistry coupled with choline acetyltransferase (ChAT) immunohistochemistry or aqueous catecholamine-fluorescence histochemistry. Compared with subprimates, there is a remarkable increase in the volume occupied by and the number of cholinergic cells contained in the nucleus basalis and nucleus tegmenti pedunculopontinus (subnucleus compacta). The elaboration of these parts of the cholinergic system is accompanied by a large extension of catecholaminergic cell groups in the midbrain (groups A8-A10), particularly the substantia nigra (pars compacta), and in the dorsolateral pontine tegmentum (A5-A7 complex). Although cholinergic and catecholaminergic soma generally occupy distinctly different regions of the brain, a close apposition of cholinergic and noradrenergic neurons occurs in the dorsolateral pontine tegmentum. In the peripeduncular region ChAT-positive cells and green fluorescent neurons of the A6-A7 complex form parallel lines and do not intermingle as has previously been demonstrated in the cat. Two distribution patterns, aggregated or disseminated, are another common feature of central cholinergic and catecholaminergic perikarya. The cholinergic neurons in the nucleus tegmenti pedunculopontinus and the catecholaminergic neurons in A6-A7 complex display both patterns. This comparative study of three transmitter systems in the baboon suggests that the cholinergic as well as the catecholaminergic neurons that give rise to ascending telencephalic and dorsal diencephalic projections undergo phylogenetic development in terms of cell number and nuclear volume.
A myeloarchitectonic atlas of the longitudinal (or mediolateral) subdivision of the cerebellum of the chicken (white Leghorn) was prepared from serial Häggqvist or toluidine-blue-stained sections of five animals. This myeloarchitectonic subdivision is based on the alternate occurrence of large fiber accumulations (LFAs) and small fiber areas (SFAs) in the cerebellar white matter and allows the distinction of a number of parasagittal fiber compartments, each of which consists of a medial LFA and a lateral SFA. The compartmental subdivision of the cerebellar white matter in mammals and birds derives its importance from the fact that essentially it corresponds to the organization of the afferent and efferent connections of the cerebellar cortex. The simple structure of the avian cerebellum makes it ideally suited for a complete description of its compartmental subdivision and may serve as a natural system of coordinates in future anatomical and physiological studies. The number of fiber compartments that can be counted in the chicken cerebellum on either side of the midline varies from six (in the narrowest folium I) to nine (in the widest folia IX and X) and is approximately the same as in mammals, in which a maximum of eight or ten compartments can be recognized. On the basis of the organization of its myeloarchitecture and the otherwise relatively scarce data on the organization of the connections of its cortex, it can, therefore, be postulated that the avian cerebellum is the homologue of the entire mammalian cerebellum. In addition, the present knowledge of the connections of the cerebellar cortex in birds indicates that the avian compartments 1-3 may correspond to the mammalian compartments A1, A2, and A3 (or X), whereas the avian compartment 4 or 5 (or both) may represent the mammalian B compartment. Lack of further anatomical data so far precludes conclusions on a possible homology between the avian compartments 6-9 and the mammalian C and D compartments.
An atlas of neurons in the brain of the crayfish Cherax destructor that are immunoreactive to antibodies raised against serotonin has been compiled from whole mount preparations. Neuronal networks of serotonin-containing cells are identified in the optic lobes and protocerebrum, in the deutocerebrum, and in the tritocerebrum. The consistency of the whole-mount technique allows 50 out of a total of about 100 immunoreactive cells to be individually identified according to their neuronal architecture or the location of their cell somata or axons. Apart from six neurons with axons in the oesophageal connectives, all the immunoreactive cells are intrinsic to the optic lobes and brain.
The organization of the medial geniculate body and adjacent posterior thalamus of the Virginia opossum was studied in Nissl-, Golgi-, reduced silver, and myelin-stained preparations. Our chief goals were to define the cytoarchitectonic subdivisions and boundaries in Nissl preparations and to reconcile these with those observed with the Golgi method and in experimental material, to present these results in an atlas of Nissl-stained sections, and to compare the chief nuclear groups in the opossum and the cat medial geniculate body. In the opossum, the ventral division consists chiefly of the ventral nucleus. The ventral nucleus is divided into two main parts: the pars lateralis and the pars ovoidea, the former being relatively smaller in the opossum. The ventral nucleus of both species contains large principal neurons with bushy, tufted dendrites and smaller Golgi type II cells. However, the opossum has far fewer Golgi type II cells, and the texture of the neuropil is correspondingly different, although the primary ascending input from the midbrain arises from the central nucleus of the inferior colliculus in both species. The dorsal division consists of the dorsal nuclei, including the suprageniculate nucleus and the caudal part of the lateral posterior nucleus, the marginal zone, and the posterior limitans nucleus. These nuclei are identified in both species, although they are much smaller in the opossum. The neurons consist of medium-size and small somata with a predominantly radiate mode of dendritic branching and a lower cell concentration than in the ventral division. In both species the afferent brain stem input comes from the inferior colliculus, the lateral tegmental area, the intercollicular tegmentum, and the superior colliculus. The medial division contains several types of cells, which are heterogeneous in form and size, most having radiating dendrites and a low cellular concentration. This division is especially smaller in the opossum, although comparable inputs arise from various auditory and non-auditory sources in the midbrain and spinal cord in both species. A large intralaminar complex of nuclei occurs in the opossum, which have a more extensive distribution than previously appreciated. They not only occupy the intramedullary laminae but form a shell around the medial geniculate nuclei and adjoining main sensory nuclei. The intralaminar complex includes the posterior limitans, posterior intralaminar, posterior, parafascicular, posterior parafascicular, central intralaminar, limitans, and central medial nuclei, and the marginal zone of the medial geniculate body.(ABSTRACT TRUNCATED AT 400 WORDS)
A detailed cytoarchitectonic atlas of the chinchilla cochlear nucleus complex was prepared in the transverse plane with the Nissl method. Subdivisions of the cochlear nucleus were defined on the basis of cell size, cell packing density, and, in some cases, on cytological features of cell types. In general, the chinchilla cochlear nucleus has an organizational plan similar to that described for other mammalian species. As in other rodents, the chinchilla has a large and well-developed dorsal cochlear nucleus consisting of three distinct layers. The ventral cochlear nucleus consists of two distinct nuclear masses, a posterior nuclear group and an anterior nuclear group, each composed of several subdivisions, which are qualitatively similar to those described for other mammals. Thus it is now possible to compare detailed observations, such as tonotopic maps, in the chinchilla with findings from the analogous cell populations in other mammals, such as the cat, with considerable precision. In the chinchilla, three cell groups, previously undescribed in mammals, have been defined and their counterparts in the cat identified.
This report provides a description of the normal developing inner ear of the zebrafish, Danio rerio, with special focus on the pars inferior. Zebrafish specimens, ranging in age from 3 to 30 days postfertilization (dpf), were processed for standard histologic sections or with a paint-fill method to show three-dimensional morphogenesis of the membranous labyrinth. Adult zebrafish (age 2 years) were also processed for inner ear paint-fills. Although development of the semicircular canals occurs rapidly (by 3 dpf), the pars inferior develops more gradually during days 5-20 postfertilization. A rudimentary endolymphatic duct emerges by 8 dpf. Differentiated hair cells of the lagenar macula are evident by 15 dpf, in a chamber located lateral and posterior to the saccule. By 20 dpf, the saccule itself is separated from the utricle, but remains connected by means of the utriculosaccular foramen. The maculae neglectae, each with differentiated hair cells, lie on the floor of the utricle near this foramen. A medial connection between the sacculi of right and left ears, the transverse canal, is also complete by 20 dpf. A ridge of mesenchyme, previously undescribed, bisects the saccule in zebrafish fry at 20-30 dpf. The images in the paint-fill atlas should provide a baseline for future studies of mutant zebrafish ears.