Arthroscopic study of the shoulder joint in fetuses.

PURPOSE: The purpose of this study was to macroscopically examine the fetal shoulder joint using arthroscopy. We attempted to identify and describe the specific characteristics of the fetal shoulder joint, how it evolves during the last few weeks of intrauterine development, and any possible variations with regard to the adult shoulder. TYPE OF STUDY: Observational anatomic case series. METHODS: We used 20 frozen fetuses with a gestational age of 24 to 40 +/- 2 weeks, obtained from spontaneous abortions. Examination was performed with standard arthroscopic surgical equipment, using a 2.7-mm optical lens. Whenever possible, we tried to use the standard arthroscopic portals. Images were obtained for comparison with the adult shoulder. RESULTS: The arthroscopic images of the fetal glenohumeral joint are similar to those of an adult shoulder, with the only differences being those related to the stage of development. In this study we observed no so-called bare spot in the glenoid cavity such as has been described in treatises on the adult shoulder joint. The arthroscopic images of the anterosuperior region of the fetal joint show more highly defined structures than in the adult shoulder, especially the coracohumeral and glenohumeral ligaments. CONCLUSIONS: To our knowledge, this is the first arthroscopic study to target the fetal shoulder joint. The results indicate minimal differences when compared with the adult shoulder joint; for some structures, particularly in the anterosuperior region, the anatomy observed was easier to discern than what is observed in adult shoulder arthroscopy. CLINICAL RELEVANCE: Our study obtained clear images of virgin shoulder joints that had never been subjected to deterioration from wear or other distorting forces. The clarity of these images is useful for locating and identifying structures in the adult shoulder.

Arthroscopic study of the knee joint in fetuses.

PURPOSE: The purpose of this study was to macroscopically examine the fetal knee joint via arthroscopy. We have attempted to identify and describe the specific characteristics of the fetal knee joint, how it evolves during the last few weeks of intrauterine development, and any possible variations with regard to the adult knee. TYPE OF STUDY: Observational anatomic case series. METHODS: We used 20 frozen fetuses with a gestational age of 24 to 40 +/- 2 weeks, obtained from spontaneous abortions. Examination was performed with standard arthroscopic surgical equipment, using a 2.7-mm optical lens. Whenever possible, we tried to use standard arthroscopic portals. Images were obtained for comparison with the adult knee. RESULTS: Suprapatellar and infrapatellar septa were an almost consistent finding. The suprapatellar septum always opened laterally and was intact in the developmentally younger specimens. We found 2 mediopatellar septa. The femoral attachment of the anterior cruciate ligament (ACL) differed in appearance from that of the adult in that it was more ribbon-like. The lateral meniscus had a more spread-out appearance than its adult counterpart, especially in the specimens of a younger gestational age. We were surprised at the easy accessibility of the popliteal hiatus and the clear arthroscopic vision we were able to obtain of the involved structures. CONCLUSIONS: To our knowledge, this is the first arthroscopic study to target the fetal knee. The results indicate minimal differences when compared with the adult knee, and for some structures, such as the popliteal hiatus, the anatomy seen was easier to discern than in adult knee arthroscopy.

Ciliary muscle in avian is derived from mesenchymal and epithelial cells.

It has long been maintained that the ciliary muscle derives from mesenchymal cells. The embryonic development of the avian ciliary muscle was studied in chick embryos from stage 25 HH to the time of hatching. Serial sections of the eye were stained routinely or immunocytochemically using the monoclonal antibody 13F4, which recognizes a cytoplasmic antigen specific for all types of muscle cells. We found that the mesenchymal immunoreactive cells, at stage 37 HH, are arranged in two distinct orientations forming the anterior and posterior portions of the ciliary muscle. At stages 38 and 39 HH the pigmented epithelium contained 13F4 positive cells, which detach from the epithelium and apparently migrate into stroma. These epithelial cells may differentiate into muscle cells. Within this same time period a progressive accumulation of myoblasts was detected between the pigmented epithelium and the ciliary muscle. Some myoblasts containing melanin were also observed. At stage 40 HH the internal portion of the ciliary muscle was visible. These findings indicate that the immunopositive epithelial cells participate in the formation of the internal portion of the muscle. We conclude that the ciliary muscle derives not only from the mesenchymal cells but also from the pigmented epithelium.

The influence of altered circulating blood volume on ventricular morphogenesis in the chick embryo: analysis by scanning electron microscopy / Influencia del volumen sanguíneo circulante alterado sobre la morfogénesis ventricular en el embrión de pollo: análisis con el microscopio electrónico de barrido

Cardiac morphogenesis represents a balance of myocardial differentiation, growth and remodelling, and congenital cardiovascular malformations likely reflect a range of similar final common pathways generated by numerous primary genetic and environmental abnormalities. In the present work, we analyzed the morphology of the developing ventricle in the chick embryo following experimental alterations in total circulating volume. In parallel experiments, we injected three different volumes of blood into a branch of the right vitelline vein at stages 22, 25 and 29 of Hamburger and Hamilton (n?10 per group). The embryos were reincubated to stage 35 of Hamburger and Hamilton and then processed for morphological analysis using scanning electron microscopy. 39% of the surviving operated embryos contained ventricular malformations, including disordered trabeculation and patterns of either cardiac dilation or cardiac hyperplasia. Despite the high prevalence of disordered trabecular morphogenesis, we identified very few ventricular septal defects. Thus, while alterations in ventricular loading conditions may alter morphogenesis, cardiomyopathic phenotypes may be separated from defects in ventricular septation (AU)

La morfogénesis cardiaca representa un balance de la diferenciación, crecimiento y remodelación miocárdica y las malformaciones cardiovasculares congénitas probablemente reflejan un rango de vías comunes finales generadas por numerosos defectos genéticos y ambientales primarios. En el presente trabajo analizamos la morfología del ventrículo en desarrollo del embrión de pollo después de alteraciones experimentales del volumen total circulante. En experimentos paralelos inyectamos tres volúmenes de sangre diferentes en una rama de la vena vitelina derecha en los estadios 22, 25 y 29 de Hamburger y Hamilton (n ?10 por grupo). Los embriones fueron reincubados hasta el estadio 35 de Hamburger y Hamilton y luego se procesaron para su análisis morfológico con el microscopio electrónico de barrido. El 39 por ciento de los embriones operados supervivientes contenían malformaciones ventriculares, que incluían una trabeculación alterada y patrones de dilatación o de hiperplasia cardiaca. A pesar de la alta prevalencia de morfogénesis trabecular alterada, identificamos muy pocos defectos septales ventriculares. Por ello, mientras que las alteraciones en condiciones de carga ventricular pueden alterar la morfogénesis, los fenotipos cardiomiopáticos pueden ser separados de los defectos en la formación del septo ventricular (AU)

Efecto de la modificación del volumen sanguíneo en la formación de las trabéculas ventriculares en corazón de embriones de pollo / Effect of the modifications of blood volumen in the formation of the ventricular trabeculas in chick embryonic

En un intento por conocer experimentalmente la importancia de los factores hemodinámicos en la morfogénesis cardíaca, diseñamos esta investigación para determinar las consecuencias que ejerce la disminución del flujo sanguíneo en el desarrollo de las trabéculas ventriculares en embriones de pollo. A tal objeto, los embriones fueron intervenidos durante el estadío 16, mediante la ligadura de la vena vitelina derecha en unos casos, e izquierda en otros, observandose sus efectos en embriones de los estadíos 35,36 y 37 mediante técnicas ultraestructurales de barrido. Nuestros resultados indican que la disminución del volumen sanguíneo causa modificaciones en la morfogénesis de las trabéculas ventriculares