ABSTRACT
In light of the controversy reported in previousstudies, we conducted this study with theobjective of using macroscopy and lightmicroscopy to elucidate the morphology of thediscomallear ligament and detail its topographicrelationship with other fibrous structuresof the temporomandibular joint (TMJ). Two human fetuses with 36 and 37 weeks of intrauterine life were used. Bundles of longitudinal fibers crossed the petrotympanic fissure forming a single ligament. Microscopicanalysis of laminae from the discomallear andanterior malleolar ligament region showed that their insertion into the malleus is a region common to both ligaments. Therefore, these findings suggest that the discomallear and anterior malleolar ligaments could be distinct portions (anterior and superior) of the sameligament. Additionally, we propose the inclusion of these ligaments in future editions of the international anatomic nomenclature (AU)
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Subject(s)
Humans , Ear, Middle/anatomy & histology , Temporomandibular Joint Disc/anatomy & histology , Fetus/anatomy & histology , Ligaments, Articular/anatomy & histologyABSTRACT
Currently, neural tube defects (NTD) have anincidence rate of 1/1000 of those born alive.Their occurrence relates to the primary neurulationperiod. In this context, there are twomain embryogenesis models that attempt toexplain neural tube closure: the continuousclosure model and the multisite closuremodel. In this work, we studied a skull withNTD from the collection of the Federal Universityof São Paulo, Paulist School of Medicine,where the cephalic perimeter and indexwere measured and the dental arcade was usedto estimate chronological age. From thisanalysis we conclude that this was a microbrachycephalicskull, with anterior fontanelledisjunction and a neural tube closure defect atsite 2, according to the multisite classificationmodel. In general, NTDs present a highdegree of clinical and etiologic heterogeneity.The causes for this broad diversity of defectsare the intrauterine involvement of teratogenicfactors, among them maternal alcoholism,use of carbamazepine duringpregnancy, and folic acid deficiency, amongothers. There are many genes potentiallyinvolved in this class of defects configuring asmultifactorial. Thus, the multisite closuremodel allows one to explain many of thesedefects by suggesting the possibility of a differentgenetic control for each closure site,together with different sensitivities to environmentalfactors, both interacting with eachother as a probable NTD etiology (AU)
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Subject(s)
Humans , Neural Tube Defects , Microcephaly , Cranial Sutures/abnormalities , Teratogens , Abnormalities, Drug-Induced/diagnosis , Brachiocephalic Trunk/abnormalitiesABSTRACT
The present study examined the ultrastructuralfeatures of the articular discs of the temporomandibularjoint (TMJ) of nine humanfetuses aging from 21 to 28 weeks. The specimenof the fetal articular discs was sectionedfrontally and sagitally and examined under thescanning electron-microscope. The ultrastructuralsurvey of the architecture of the articulardisc revealed three bands composed of fibrocartilaginoustissues in the articular disc:namely, 1) anteromedial longitudinal fibers,the dominant component in the superior andinferior portions; 2) anteroposterior transversalfibers, 3) central diagonal fibers. The centralportion of the articular disc showedscattered blood vessels containing erythrocytes.To our knowledge, this is the firstdescription of the presence of blood vessels inthe central articular of the human TMJ articulardisc. This evidence is also lacking inclassic textbooks of Anatomy and Developmental Biology (AU)
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Subject(s)
Humans , Temporomandibular Joint Disc/blood supply , Fetus/ultrastructure , Microscopy, Electron, Scanning/methodsABSTRACT
It is shown that lagged correlations for and cross-correlations between observed hemispheric-mean temperature data differ markedly from those for unforced (control-run) climate model simulations. The differences can be explained adequately by assuming that the observed data contain a significant externally forced component involving both natural (solar) and anthropogenic influences and that the global climate sensitivity is in the commonly accepted range. Solar forcing alone cannot reconcile the differences in autocorrelation structure between observations and model control-run data.
