Sagittal Growth of the Nasomaxillary Complex during the Second Trimester of Human Prenatal Development

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66545/2/10.1177_00220345650440010401.pd

Tooth Size and Position Before Birth

No uniformity exists in the arrangement of the deciduous anterior teeth before birth. The deciduous incisors achieve a substantial amount of their final mesiodistal width at an early stage. Jaw growth in the anterior region during the last three months before birth appears not to exceed the increase in mesiodistal crown dimensions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67680/2/10.1177_00220345720510013301.pd

Síndrome da medula presa: registro de dois casos

Registro de dois casos da síndrome de medula presa nos quais o estabelecimento correto do diagnóstico permitiu adotar conduta terapêutica adequada. Esta consiste na ressecção cirúrgica do filum terminale. São comentados aspectos embriológicos e fisiopatogênicos de interesse à síndrome, bem como são analisadas suas manifestações clínicas principais, os exames complementares que possibilitam o diagnóstico, particularmente a mielografia, e aspectos da terapêutica cirúrgica

Development of extrinsic innervation in the abdominal intestines of human embryos

Compared to the intrinsic enteric nervous system (ENS), development of the extrinsic ENS is poorly documented, even though its presence is easily detectable with histological techniques. We visualised its development in human embryos and foetuses of 4–9.5 weeks post-fertilisation using Amira 3D-reconstruction and Cinema 4D-remodelling software. The extrinsic ENS originated from small, basophilic neural crest cells (NCCs) that migrated to the para-aortic region and then continued ventrally to the pre-aortic region, where they formed autonomic pre-aortic plexuses. From here, nerve fibres extended along the ventral abdominal arteries and finally connected to the intrinsic system. Schwann cell precursors (SCPs), a subgroup of NCCs that migrate on nerve fibres, showed region-specific differences in differentiation. SCPs developed into scattered chromaffin cells of the adrenal medulla dorsolateral to the coeliac artery (CA) and into more tightly packed chromaffin cells of the para-aortic bodies ventrolateral to the inferior mesenteric artery (IMA), with reciprocal topographic gradients between both fates. The extrinsic ENS first extended along the CA and then along the superior mesenteric artery (SMA) and IMA 5 days later. Apart from the branch to the caecum, extrinsic nerves did not extend along SMA branches in the herniated parts of the midgut until the gut loops had returned in the abdominal cavity, suggesting a permissive role of the intraperitoneal environment. Accordingly, extrinsic innervation had not yet reached the distal (colonic) loop of the midgut at 9.5 weeks development. Based on intrinsic ENS-dependent architectural remodelling of the gut layers, extrinsic innervation followed intrinsic innervation 3–4 Carnegie stages later