There is no agreement in the literature as to the time of the onset and progress of the vertebral column ossification. The aim of the present study was to determine the precise sequence of ossification of the neural arches and vertebral centra.Histological and radiographic studies were performed on 27 human foetuses aged from 9 to 21 weeks. It was found… (More)
In embryos at stage 13th vestibulocochlear ganglion forms a complex structure with the geniculate ganglion. The geniculate ganglion is placed rostrally and may be distinguished from the vestibulocochlear ganglion. Also at this stage there is a sign of differentiation of the vestibular and cochlear ganglia.
The formation of the myelin sheath of the human hypogastric nerves was studied by electron microscopy in a foetus of 23 weeks of postovulatory age (220 mm C-R length). In the investigated foetus the hypogastric nerves were mainly composed of bundles of unmyelinated fibres. The myelinated fibres were seen to be at different stages of myelination. Well… (More)
The formation of the myelin sheath of the human phrenic nerve has been studied by electron microscopy in fetuses aged 15, 17, and 23 postovulatory weeks. At 15 weeks, the phrenic nerve is composed mainly of large bundles of axons surrounded by lemmocyte processes. However, fibres at the beginning of myelination are present and show one or one and a half… (More)
The cochlear ganglion was investigated in serially sectioned human embryos at developmental stages 18 and 19 (44-46 postovulatory days). During this period the cochlear ganglion is separated from the vestibular ganglion, and it is adjacent to the cochlear duct. In embryos of investigated stages fibers of the cochlear ganglion enter the nuclei in the brain.
A study was made on 18 embryos of developmental stages 13-15 (5(th) week). Serial sections made in horizontal, frontal, and sagittal planes were stained with routine histological methods and some of them were treated with silver. In embryos of stage 13, the otic vesicle is at the rhombomere 5, and close to the vesicle is the facial-vestibulocochlear… (More)
Ultrastructural study was conducted on the superior cervical sympathetic ganglia in human foetus aged 23 weeks. It was shown that in investigated foetus the nerve fibres in the ganglion were in different phases of myelination. Also growth cones, which present evidence of still growing fibres, were observed.
The study was conducted on 6 human embryos at stage 13. It was found that the facial-vestibulocochlear complex is closely related to the otic vesicle, and the particular components of that complex may be distinguished. They show different cellular arrangement and shape. The neural crest cells migrating from the dorsal hindbrain are continuous with cells… (More)