Study of the relationship between the suprascapular artery and the brachial plexus.

The literature concerning the relationship of the suprascapular artery with the brachial plexus is quite limited. The aims of this study were to investigate the different types of relationships between the suprascapular artery and the brachial plexus trunks and to try to clarify their prevalence in the European population. Our study involved the dissection of 100 upper extremities from adults, all of European origin (55 women, 45 men). In the classic description, the suprascapular artery passes in front of the brachial plexus (group A) in the majority of cases, then behind the omohyoid before reaching the superior border of the scapula. There are two other types of relationship with the brachial plexus: the suprascapular artery can pass between the trunks of the brachial plexus (group B) or the artery can pass behind the brachial plexus (group C). To our knowledge there has been only one study on the subject, carried out by Kosugi et al. Our results show a not inconsiderable number of variations in the relationships between the suprascapular artery and the brachial plexus (29%). Although no differences were noted between the sexes, a significant number of individual variations were revealed by the comparative study of dissections performed on both upper extremities of the same individual. Our results suggest that new studies are required to complete these initial anatomical results observed on a small sample of subjects of European origin. The French version of this article is available in the form of electronic supplementary material and can be obtained by using the Springer LINK server located at http://dx.doi.org/10.1007/s00276-002-0026-5.

Variations of relative anteversion of the femoral neck during walking.

Based on the geometric model developed by Netter [11], we determined the different positions of the femoral neck during monopodal support in walking in relation to a fixed frontal plane of reference (relative anteversion). This "relative anteversion" ranges on average from 24 degrees of retroversion at the beginning of support to 15 degrees of anterversion at the end if loading. We then studied the relations possibly existing between relative anteversion and acetabular orientation on the one hand, and the orientation of the resultant of the articular stresses on the other (both being variables during monopodal support in walking). The results showed that relative anteversion is well correlated with variations of position of the acetabulum since, at most, the deviation between the respective axes did not exceed the anatomic deviation due to absolute anteversion of the femoral neck and acetabulum. Lastly, analysis of the relations obtained with the orientation of the resultant of the articular stresses allowed a better comprehension of the functional distribution of forces.

Biomechanics of the hip: forces exerted during walking.

Since the work of Pauwels, the forces exerted on the coxofemoral joint during walking have been studied either in different spatial planes (frontal, sagittal and horizontal) or by three-dimensional spatial analysis. Starting from the findings of our own studies, our aim was to compare the two methods of analysis (two-dimensional and three-dimensional) in order to provide a better understanding of the benefits and limitations of each method. In pursuit of this aim, we studied the pressure forces exerted on the coxofemoral joint, using a geometric plane technique following a method similar to that of Pauwels [20], and with a three-dimensional modelling technique using the finite element method. The material, taken from the published literature, was the same in both our studies. The results are expressed in terms of the size and orientation of the pressure force exerted on the coxofemoral joint during the monopodal weightbearing phase of walking. A comparison of these two methods of analysis clearly demonstrates the simplicity of two-dimensional analysis (which must incorporate as a minimum the frontal plane and the sagittal plane) and the richness of the three-dimensional analysis. The latter method, by appropriate manipulation of the information obtained, provides a starting point for computer simulations performed with the aim of testing a biomechanical or therapeutic hypothesis.

[Stress and quantification of pressures borne by the hip in unilateral support in the sagittal plane. I]. / Etude des sollicitations et quantification des pressions subies par la hanche en appui monopodal dans le plan sagittal.

Thanks to the works of Pauwels, the pressures sustained by the hip during unilateral weightbearing in the frontal plane are now well known and have given rise to a number of surgical applications. Considered as negligible by Pauwels, the sagittal plane has been little studied; in fact, with Pauwels' methodology, but taking into account the muscular moments, it appears that the forces exerted in the sagittal plane are far from being negligible and vary, according to the phase of weightbearing, from once the weight of the body (weightbearing on the sole) to two and a half times the weight of the body (weightbearing on the heel).

[Changes in the pressure borne by the hip during the phase of unilateral support in locomotion. II]. / Variation des pressions subies par la hanche durant la phase d'appui monopodal de la marche.

Adopting the methodology that we have just described, our study completes that of Pauwels in that we take into consideration the pressures sustained by the hip not only in the frontal plane but also in the horizontal and sagittal planes during the phase of unilateral weightbearing when walking. Thanks to the work of Braune and Fischer (1) the forces exerted on the hip are now well known and are represented by the weight of the body, the muscular forces and the dynamic forces generated by walking. From these data, we have been able to quantify the pressures sustained by the hip in each plane during the different phases of unilateral weightbearing when walking (weightbearing on heel, sole and toes).

[Non-Hodgkin's large B cell malignant lymphoma localized in the anterior mediastinum. Apropos of 2 cases]. / Lymphome malin non Hodgkinien à grandes cellules de type B localisé dans le médiastin antérieur. A propos de deux cas.

The authors present two cases of a specific variety of malignant non Hodgkin's lymphoma large B cell, characterised by an initial localisation in the anterior mediastinum where the tumors were adhesive and infiltrating, by the fact they appear, most of the time, in young women, by their usual resistance to treatment and by the presence of severe fibrosis on histological examination.