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Posterior Border (posterior + border)
Selected AbstractsEgg capsules of the dusky catshark Bythaelurus canescens (Carcharhiniformes, Scyliorhinidae) from the south-eastern Pacific OceanJOURNAL OF FISH BIOLOGY, Issue 4 2010F. Concha The external morphology of the egg capsule of Bythaelurus canescens and its fixation to the substratum are described. Bythaelurus canescens egg capsules are typically vase-shaped, dorso-ventrally flattened, pale yellow in colour when fresh and covered by 12,15 longitudinal ridges. The anterior border of the capsule is straight, whereas the posterior border is semicircular. Two horns bearing long, coiled tendrils arise from the anterior and posterior ends of the capsule. The presence of longitudinal ridges and long coiled tendrils at both anterior and posterior ends of the capsule readily distinguish these egg capsules from those of other chondrichthyans occurring in the south-east Pacific Ocean. [source] CRANIAL CREST DEVELOPMENT IN THE AZHDARCHOID PTEROSAUR TUPUXUARA, WITH A REVIEW OF THE GENUS AND TAPEJARID MONOPHYLYPALAEONTOLOGY, Issue 4 2006DAVID M. MARTILL Abstract:, A portion of pterosaur skull from the Romualdo Member of the Santana Formation (?Albian,?Turonian, Cretaceous) of north-east Brazil provides new data on the morphology and ontogeny of azhdarchoid pterosaur cranial crests. The specimen consists of parts of the cranial bones posterodorsal to the nasoantorbital fenestra, including partial nasals, lacrimals, frontals and possibly the parietals. A posterodorsally directed premaxillary crest with a concave posterior border is located dorsal to the posterior border of the nasoantorbital fenestra. A well-defined suture indicates overlapping, posterodorsally directed growth of the premaxilla over the skull roof, suggesting that the generation of the premaxillary crest is a late ontogenetic feature and thus probably related to sexual display. The systematics of Tupuxuara and its relationship to other azhdarchoids is reviewed and a cladistic analysis of the group is presented. Tupuxuara is found to be the sister-taxon to Azhdarchidae. Tupuxuara longicristatus Kellner and Campos, 1988 is argued to be the only valid named species in this genus and Thalassodromeus Kellner and Campos, 2002 is considered a junior subjective synonym of this taxon. As originally conceived, Tapejaridae is paraphyletic: a new, more restrictive version of Tapejaridae (including Tapejara and Sinopterus dongi) might exist, but its monophyly is weakly supported. Furthermore, Tapejara was found to be paraphyletic in all trees. [source] Insights into the molecular basis of rhegmatogenous retinal detachmentACTA OPHTHALMOLOGICA, Issue 2009PN BISHOP Purpose Factors that determine the likelihood of developing posterior vitreous detachment and subsequent rhegmatogenous retinal detachment (RRD) include (i) the degree of vitreous liquefaction (ii) the strength of post-basal vitreoretinal adhesion and (iii) the topology of the posterior border of the vitreous base. The purpose of these studies was to investigate each of these using a combination of ultrastructural and molecular techniques. Methods Ultrastructural studies of the human vitreous and vitreoretinal interface were performed in combination with various antibodies and cationic dyes. Biochemical studies were performed on extracted vitreous components. Results The resultant data suggest that: (i) vitreous liquefaction is caused by the aggregation of vitreous collagen fibrils and this is due to a loss of type IX collagen proteoglycan from the fibril surfaces; (ii) interactions between heparan sulphate proteoglycans in the inner limiting lamina and components on the surface of cortical vitreous collagen fibrils contribute to postbasal vitreoretinal adhesion; (iii) the posterior border of the vitreous base migrates posteriorly with aging due to the synthesis of new vitreous collagen by the peripheral retina. Conclusion The molecular basis of RRD is starting to be unravelled. Furthering our understanding of the underlying molecular processes may lead to the development of novel therapeutic strategies to treat RRD and other vitreoretinal disorders. [source] Wilhelm Erb and Erb's pointCLINICAL ANATOMY, Issue 5 2007R. Shane Tubbs Abstract Wilhelm Erb is well known for his early contributions to the field of neurology and was an eminent physician of his time. One area described by him and that still bears his name is Erb's point. This point located just superior to the clavicle was used by Erb to transcutaneously elicit contractions of various proximal arm muscles with electrical stimulation. Many have mistakenly interchanged the terms "Erb's point" and "nerve point" when describing the point of emergence of the cutaneous branches of the cervical plexus near the posterior border of the sternocleidomastoid muscle. We present a brief history of Erb's adult life and review his original description of his supraclavicular point and contrast this to the so called nerve point of the posterior cervical triangle. Clinicians and anatomists should be aware of the discrepancy often found in the literature between these two terms. Clin. Anat. 20:486,488, 2007. © 2006 Wiley-Liss, Inc. [source] Anatomical variations of the sural nerveCLINICAL ANATOMY, Issue 4 2002Pasuk Mahakkanukrauh Abstract An anatomical study of the formation of the sural nerve (SN) was carried out on 76 Thai cadavers. The results revealed that 67.1% of the SNs were formed by the union of the medial sural cutaneous nerve (MSCN) and the lateral sural cutaneous nerve (LSCN); the MSCN and LSCN are branches of the tibial and the common fibular (peroneal) nerves, respectively. The site of union was variable: 5.9% in the popliteal fossa, 1.9% in the middle third of the leg, 66.7% in the lower third of the leg, and 25.5% at or just below the ankle. One SN (0.7%) was formed by the union of the MSCN and a different branch of the common fibular nerve, running parallel and medial to but not connecting with the LSCN, which joined the MSCN in the lower third of the leg. The remaining 32.2% of the SNs were a direct continuation of the MSCN. The SNs ranged from 6,30 cm (mean = 14.41 cm) in length with a range in diameter of 3.5,3.8 mm (mean = 3.61 mm), and were easily located 1,1.5 cm posterior to the posterior border of the lateral malleolus. The LSCNs were 15,32 cm long (mean = 22.48 cm) with a diameter between 2.7,3.4 mm (mean = 3.22 mm); the MSCNs were 17,31 cm long (mean = 20.42 cm) with a diameter between 2.3,2.5 mm (mean = 2.41 mm). Clinically, the SN is widely used for both diagnostic (biopsy and nerve conduction velocity studies) and therapeutic purposes (nerve grafting) and the LSCN is used for a sensate free flap; thus, a detailed knowledge of the anatomy of the SN and its contributing nerves are important in carrying out these and other procedures. Clin. Anat. 15:263,266, 2002. © 2002 Wiley-Liss, Inc. [source] Placement of Brånemark implants in the maxillary tuber region: anatomical considerations, surgical technique and long-term resultsCLINICAL ORAL IMPLANTS RESEARCH, Issue 1 2009Arne Ridell Abstract Background: Fixture placement in the tuber area is one way to overcome the problem of insufficient bone volume for routine implant surgery in the posterior maxilla due to severe resorption of jawbone and an extensive enlargement of the maxillary sinus. However, little is known about the long-term results. Purpose: The aim of this study was to retrospectively evaluate the survival rate and marginal bone conditions at fixtures placed in the tuber region of the maxilla. Material and methods: Twenty-one patients previously treated with at least one implant in the tuber region of the maxilla were included in this retrospective analysis. A total of 23 standard Brånemark System fixtures with a turned surface had been surgically placed in the tuber regions and 71 additional implants in adjacent areas to support fixed dental bridges. All implants were allowed to heal for 6,8 months before abutment connection and following prosthetic treatment. The patients were radiographed after 1,12 years for evaluation of marginal bone levels. In addition, the relation between the apex of the fixture in the tuberosity area and the posterior border of the maxilla was measured. Results: Twenty of the 21 patients representing 22 tuber and 64 additional implants were radiographically evaluated. No implants in the tuber areas were lost during the follow-up whereas two fixtures in the anterior region had to be removed, one before loading and the other after 4 years of loading not interfering with the prosthesis stability. The mean marginal bone level at tuber implants was situated on average 1.6 mm (SD 1.1, n=22) from the abutment-fixture junction, whilst the other implants showed an average bone level of 1.9 mm (SD 0.8, n=64). The results were similar when comparing partially and totally edentulous patients. Conclusion: The present retrospective study shows good clinical outcome with standard Brånemark fixtures placed in the tuber region of the posterior maxilla using a two-stage procedure. In appropriate cases where bone of adequate volume and density is available, our data indicate that the technique can be used as an alternative to more extensive surgery and especially to the sinus lift procedure. However, prospective comparative studies are needed in order to evaluate the efficacy of the described technique for this purpose. [source] Ultrastructure of the hindgut of Drosophila larvae, with special reference to the domains identified by specific gene expression patternsJOURNAL OF MORPHOLOGY, Issue 2 2001Ryutaro Murakami Abstract The hindgut of Drosophila larvae consists of nine domains that have been distinguished by specific gene expression patterns. In the present study, we examined the ultrastructure of the hindgut of Drosophila larvae, with special reference to the domains, in order to determine whether or not the domains are morphologically distinct functional units. Each domain showed specific ultrastructural features that suggested specific corresponding functions. According to the morphological features, terms are proposed for each domain: the imaginal ring; the "pylorus," which has a thick cuticular layer and well-developed sphincter muscles; the "large intestine," which occupies a major middle portion of the hindgut and has a unique dorsal and ventral subdivision; "border cells," which delineate the anterior and posterior borders of the large intestine and the border between the dorsal and ventral domains of the large intestine; and the "rectum," which is situated at the posterior end of the hindgut and has a thick cuticular layer and sphincter muscles. The morphological features indicate that the large intestine has active absorptive activities. The domains, which have been distinguished by gene expressions, were demonstrated to be functional tissue units of the gut. J. Morphol. 248:144,150, 2001. © 2001 Wiley-Liss, Inc. [source] Shape, height, and location of the lingula for sagittal ramus osteotomy in ThaisCLINICAL ANATOMY, Issue 7 2009P. Jansisyanont Abstract This study aims to investigate the shape, height, and location of the lingula in relation to surrounding structures for sagittal ramus osteotomy. Dried Thai mandibles were studied and compared with other races. From both sides of 92 mandibles, the shape of the lingula was classified into triangular, truncated, nodular, or assimilated types. Of 92 mandibles, 146 sides with at least a premolar and a molar on the same side were selected for distance measurement. Height of the lingula was measured from the lingular tip to the mandibular foramen. The location was determined by five distances from the lingular tip to: the anterior and the posterior borders of the mandibular ramus, the mandibular notch, the distal surface of the mandibular second molar, and the occlusal plane. The results showed that truncated lingulae were most frequently found (46.2%) and most appeared to be bilateral (71.7%). Triangular, nodular, and assimilated shapes presented in 29.9%, 19.6%, and 4.3%, respectively. The mean lingular height was 8.2 ± 2.3 mm. The lingula was located at 20.6 ± 3.5 mm from the anterior border of the mandibular ramus and 16.6 ± 2.9 mm from the mandibular notch. In the majority of the mandibles studied, the lingula was located above the occlusal plane. In conclusion, the shape and metric characteristics of the lingula in relation to surrounding structures in Thais vary from other races. All parameters associated with the lingula should be considered for sagittal ramus osteotomy to avoid intraoperative complications. Clin. Anat. 22:787,793, 2009. © 2009 Wiley-Liss, Inc. [source] | ||||||||||||||||