ABSTRACT
BACKGROUND: Because external laryngeal nerve (ELN) iatrogenic damage is frequent during neck surgery, its precise localization has been highly recommended. This study analyzes the different surgical landmarks previously proposed and the anatomy of the collateral and terminal branches of the ELN. METHODS: The necks of 157 (77 men and 80 women) human adult embalmed cadavers were examined. The ELN origin, length, and relationship to different landmarks were recorded and results statistically compared with those previously reported. RESULTS: The ELN is located deep to the ascending pharyngeal vein in 100% of patients. In most patients, it crosses the carotid axis at the thyroid artery origin level (47% of patients), passes medial to it (89% of patients), and shows an intramuscular trajectory through the inferior constrictor of the pharynx (80% of patients). CONCLUSION: The ELN position, in relation to classical landmarks, is highly variable. The most reliable relationships are those with the ascending pharyngeal vein or with the superior thyroid artery.
Subject(s)
Anatomic Landmarks , Laryngeal Nerves/anatomy & histology , Aged , Aged, 80 and over , Cadaver , Female , Humans , Male , Middle AgedABSTRACT
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Subject(s)
Humans , Anatomy/education , Dissection/education , Cadaver , Tissue and Organ Procurement/trendsABSTRACT
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.
Subject(s)
Chick Embryo/growth & development , Ciliary Body/embryology , Epithelial Cells/cytology , Mesoderm/cytology , Muscle, Smooth/embryology , Animals , Morphogenesis , Pigment Epithelium of Eye/embryologyABSTRACT
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)
