Search

A rare variation of the azygos system, found in an 84 year old man, is described. A "double-columned" azygos system runs in front of the spine, and the azygos major crosses the superior lobe of the right lung and enters the right subclavian vein.

Vascular and bronchial endocasts represent a useful instrument to study the ramification pattern of these structures. Casts have been made from different materials, such as waxes in ancient times and, more recently, silicon-like compounds or resins (see e.g. Mercox) to study the finest details. These techniques are valuable for small specimens, whereas they are inadequate for very large organs, where technical difficulties require the development of specific instrumentation. In this study we present a new simple injection technique, based on expanded polyurethane, which allows preparing vascular and bronchial trees for macroscopic and microscopic studies. The new injection technique is very easy to carry out, since the propulsion is provided by compressed air, and it does not require special instrumentation. To this aim, endocasts of the entire tracheal-bronchial tree and casts of vascular kidney from different animals were prepared. The specimens have a very low weight, show the finest ramifications, and are very stable and resistant to mechanical stress. To examine microscopically the details of the casts, specimens from the kidney cast were also analyzed by scanning electron microscopy, revealing good preservation of microcirculatory structures, functional sphincters and endothelial cell impressions. Therefore, the technique may be useful for macroscopic studies of large specimens, retaining sufficiently fine details.

Recent data from animal studies allow us to understand how the optic commissure formed. However, their validity in humans has not yet been demonstrated. Clues from human teratological cases provide useful information to test the validity of animal models and suggest other morphogenetic mechanisms. Janiceps are non-viable, rare cases of co-joined embryos fused along the frontal plane, with two composite faces, half formed by each of the embryos. Their development after fusion is of interest to study the optic chiasm. The analysis of the optic nerves and of the skull by magnetic resonance imaging or direct inspection of three different cases of Janiceps showed a shared hypophyseal fossa that laterally could contain a compound optic commissure between the eyes of the same composite face (heterologues), but not between the eyes from the same individual (homologue). The current model of the optic commissure formation correctly predicts these findings in humans because the optic commissure are driven toward the midline by local factors and not by target regions. However, our data suggest that the overall geometry of the region is important for a successful decussation of the axons, and additional mechanisms are involved in midline differentiation.

The deep palmar circulation is constituted by the deep palmar arch. In most cases this is a complete arch formed by the radial artery and its continuation to a deep branch of the ulnar artery. In a few cases, the deep palmar circulation is formed only by the radial or the ulnar artery. Only rarely is there a complete absence of the deep palmar arch. A series of 60 vascular casts was examined in order to identify the primary variants of the deep palmar arterial supply. Four anatomic patterns were identified: (1) radioulnar (66.67%); (2) radial-anastomotic (21.67%); (3) radial (8.33%), and (4) ulnar (3.33%). Two distinct types of the radioulnar variant were observed, a proximal and a distal one, named according to the origin of the deep palmar branch.

Summary This work documents the progressive gain in knowledge on renal anatomy acquired by anatomists from Galen to Malpighi. Galen, with albeit his rather imaginative explanations, was the first anatomist to recognize the urine producing function of the kidney. His influence was felt up to the Middle Ages; his followers imagined the presence of two cavities within the kidney that were separated by a porous membrane that they called the “colatorium” which was capable of filtering the urine from the blood. It was only later that Berengario da Carpi, divorcing himself from Galenic dogmatism, finally dismissed the presence of the colatorium. He described the renal papillae and gave the first elementary model of renal vascularization. Further important progress was due to the studies of Falloppius and Eustachius who brought contemporary understanding of renal structure to the limit of what could be seen with the unaided eye. They distinguished the difference between the unilobar canine kidney and the human multilobar organ, they also described the minor and major calyces and, furthermore, guessed at the canalicular structure of its parenchyma. Highmore was then responsible for the description of the archiform vessels which he hypothesized as an arterio-venous anastomotic net between the renal cortex and medulla. With the invention of the microscope, new doors opened for the study of renal structure. Bellini proved the canalicular organization of the parenchyma and, moreover, described the interlobular vessels. Malpighi then described the glomerulus and its relation to the intrarenal excretory ducts. The basis had now been laid for the beginning of modern nephrology.

The relationship between the superior mediastinal organs has been investigated in the adult and the newborn. It was found that this region could be represented by a geometrical schematization based on the correlations that exist among the vascular and nervous elements that lie on the right mediastinal wall. A vascular triangle, a vascular-nervous triangle and a retro-vagal square are described. The size of these forms and their relations with the organs they enclose varies depending on the build of the subject being examined in this area, particularly from a teaching point of view.