Background: The femoral vein diameter is a critical factor when assessing endoprosthetic valve size for the treatment of chronic venous insufficiency. To examine the previously stated correlation between body mass index and femoral vein diameter and to re-assess the anatomical and physiological demands for a valve implant for chronic venous insufficiency treatment, we measured the femoral vein diameter in 82 subjects. Method: Femoral vein diameters (164 legs) were measured with B-mode sonography both in supine position at rest and in upright position during Valsalva maneuver. Result: The mean femoral vein diameter differed significantly between supine position (13.6 ± 3.0 mm) and upright position (16.4 ± 2.6 mm). Males possessed a significant bigger diameter than females. A significant positive correlation between femoral vein diameter and body mass index was observed. Conclusion: Assuming an increased femoral vein diameter due to obesity would further impair valve functionality by increasing distance between both valve cusps. For the development of artificial venous valves, it is crucial to consider patient- and condition-dependent vein dilation.

Within decapod crustaceans, Anomura is the phenotypically most disparate taxon, ranging from hermit crabs to squat lobsters to crab-like representatives. Curiously, not only did the crab-like habitus evolve independently from the ‘true’ crabs (Brachyura), it also evolved three times independently within anomurans. This process has been called ‘carcinization’ by the English zoologist Lancelot Alexander Borradaile in 1916. In this paper we summarize the results of our recent studies into the evolution of the crab-like morphotype (i.e. carcinization) and into possible structural dependences (i.e. coherences) between the external morphology of a crab-like habitus and inner organs. A micro-computer tomography and computer-aided 3D reconstruction-based comparison between the various crab-like taxa shows that amazingly similar structural coherences exist across all these lineages between the external characters of the crab-like habitus and internal characters. We were even able to trace complex coherence concatenations, or ‘coherence chains’, between various structures. These new findings greatly enhance our knowledge and understanding of the evolutionary transformation into a ‘crab’, particularly in the context of causal and coherence morphology. Although enormous morphological disparity is observed in the internal anatomy of the crab-like taxa, reflecting the fact that the evolution of the crab-like habitus was indeed convergent, various corresponding dependences are found across the different lineages between the external characters of a crab-like habitus/morphotype and inner structures. In other words, as a result of carcinization certain structural coherences led to the specific internal anatomical patterns found in crab-like forms. There is no reason to assume that ‘evolutionary tendencies’ or any such vague concept played a role.

Parasitic barnacles (Cirripedia: Rhizocephala) are highly specialized parasites of crustaceans. Instead of an alimentary tract for feeding they utilize a system of roots, which infiltrates the body of their hosts to absorb nutrients. Using X-ray micro computer tomography (MicroCT) and computer-aided 3D-reconstruction, we document the spatial organization of this root system, the interna, inside the intact host and also demonstrate its use for morphological examinations of the parasites reproductive part, the externa. This is the first 3D visualization of the unique root system of the Rhizocephala in situ, showing how it is related to the inner organs of the host. We investigated the interna from different parasitic barnacles of the family Peltogastridae, which are parasitic on anomuran crustaceans. Rhizocephalan parasites of pagurid hermit crabs and lithodid crabs were analysed in this study