Formation of the vertebral arches of the cervical, thoracic and lumbar vertebrae in early human foetuses

Fusion of the neural arches was studied in 6 serially sectioned human foetuses aged 9 and 10 weeks. In foetuses of 9 weeks, the completion of arches was observed in the cervical, upper thoracic, and middle thoracic regions of the vertebral column. During the 10th week of development, fusion of neural processes progresses in the lower thoracic and upper three lumbar vertebrae. (Folia Morphol 2010; 69, 3: 177-179

Innervation of the human cervical and thoracic vertebrae at eight postovulatory weeks

The nerves to the cervical and thoracic vertebrae were traced in 10 serially sectioned human embryos. It was found that the vertebral bodies receive nerve fibres from the trunks of the spinal nerves, anterior branches and meningeal branches of the spinal nerves, and from the sympathetic trunks. Slender twigs from the trunk of the spinal nerve arise close to the spinal ganglion and terminate in the posterior and lateral surfaces of the vertebrae. Fibres from the anterior branches of the spinal nerves terminate in the lateral and anterior surfaces of the vertebrae. Thin rami from the sympathetic trunk reach the anterior surface of the vertebrae

The first appearance of sympathetic ganglia in human embryos at stage 13

The primordia of the sympathetic trunk ganglia were traced on serial sections of 10 embryos at stage 13 (32 postovulatory days). It was found that in all embryos, these primordia were present in the thoracic level T4 to T9 and they appeared as scattered aggregates of cells lying dorsally and laterally to the dorsal aortae

Ossification of the vertebral column in human foetuses: histological and computed tomography studies

There is no agreement in the literature as to the time of the onset and progress ofthe vertebral column ossification. The aim of the present study was to determinethe precise sequence of ossification of the neural arches and vertebral centra.Histological and radiographic studies were performed on 27 human foetuses agedfrom 9 to 21 weeks. It was found that the ossification of vertebrae commencesin foetuses aged 10 and 11 weeks. Ossification centres appear first for neuralarches in the cervical and upper thoracic vertebrae and by the end of 11th weekthey are present in all thoracic and lumbar neural arches. In the vertebral centrain foetus of 10 weeks ossification was found in the lower 7 thoracic and firstlumbar vertebrae. By the end of 11th week ossification is present in the lower4 cervical, all thoracic, all lumbar and 4 sacral vertebral centra. The study indicatesthat ossification of the neural arches proceeds in the craniocaudal direction,whereas in the vertebral centra it progresses from the lower thoracic vertebraeinto both directions. Different shapes of ossification centres were also described

Rare variations of hepatic arteries in association with variable origin of gastroduodenal artery found in multidetector computed tomography angiography

Three rare anatomical variations were found during study on hepatic arterial vascularisation in multidetector computed tomography angiography. In the first described variation the common hepatic artery (CHA) arises from the celiac trunk (CTr) and supplies right hepatic lobe. The left lobe of the liver is supplied by aberrant left hepatic artery originating as a common trunk with the left gastric artery and the splenic artery. This variation may correspond to the type 2 in Michels’ classification coexisting with one of three possible patterns of the CTr division (when the CHA is the first branch of the CTr and the gastrosplenic trunk is the second one). The second variation corresponds to the very early bifurcation of the CHA arising from the CTr. Both, the right and left hepatic arteries originate separately from the CTr. The gastroduodenal artery (GDA) originates from the left hepatic artery. It may be regarded as the variation of most common type 1 according to Michels. In the third case the CHA gives raise to the GDA and terminates as the right hepatic artery supplying the right lobe of the liver only. The proper hepatic artery is missing and the left hepatic artery arises from the GDA. This variation does not correspond to any types of Michels’ classification.

Early development of the facial nerve in human embryos at stages 13–15

Study was made on 16 human embryos at developmental stages 13–15 (fifth week). The facial nerve was traced on serial sections made in three planes (sagittal, frontal and horizontal) and stained with routine histological methods and impregnated with silver. In embryos at stage 13 the facial ganglion forms a complex structure with the vestibulocochlear ganglion. It is of fusiform shape in contact with epipharyngeal placode and is located anteriorly and ventrally to the vestibulocochlear ganglion. In embryos at stage 14 the facial ganglion separates from the vestibular and cochlear ganglia and the chorda tympani as the first branch appears. During stage 15 the main trunk of the facial nerve elongates and the greater petrosal nerve originates at the level of the facial ganglion and above the origin of the chorda tympani