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The development of new leisure activities such as walking has spread the use of the backpack as a means of carrying loads. The aim of this work was to present a way of defining the movements imposed on the trunk by this type of load carrying. A 20 kg load situated at the thoracic level (T9) of the trunk, was placed in a backpack (2.5 kg). The 12 subjects were average mountain guides of Auvergne region, intermediate level and complete beginners. External markers were glued to the projecting contours of the spinous processes of the C7, T7, T12, L3 and S1 vertebrae, the shin and the external occipital tuberosity (EOT). Using a Vicon 140 3-D system we measured the effective mobility of the different spinal segments in the sagittal plane during one step. For every subject, we noticed a significant decrease of the effective inter-segmental mobility (EISM) between S1-L3-T12 (p < .01) while backpacking a 22.5 kg load. A decrease of EISM also appeared at the next level between L3-T12-T7 (p < .05). An increase of the EISM between T7-C7-EOT was noted (p < .05). We supposed that strength loss of the back muscles and/or angular oscillations of the trunk could be a common cause of symptoms during backpacking. The subjects using this type of load carrying have to adopt an adequate position of the lumbar, dorsal and cervical vertebrae.

Finite element modelling of the human lumbar vertebral column employs data-processing procedures for study of the linear and nonlinear elasticity of materials such as are currently used in mechanics or in civil engineering. Thanks to developments in computer science, requiring a close collaboration between doctors and engineers, we put forward in this preliminary study a linear computerised model of the lumbar column comprising 4824 meshes and 6813 nodes. By reducing the simplificatory hypotheses and integrating new parameters, this model as developed is capable of important clinical applications in surgery and ergonomics.

Opto-electronic systems utilising measurement of displacement of skin markers allows study of movement in the living subject. The authors have used this method in a kinematic study of the thoracic and lumbar spine measuring the displacement of skin markers placed over the spinous processes. It was possible to approach the physiological state of these complex movements once the apparatus had been calibrated to the correct level, and the error margins minimised. Repeated measurements confirmed the reliability of this method even if movement of the skin with respect to the bony reference points introduced some margin of error. Three dimensional displacement of the vertebrae were measured during voluntary movements of the spine demonstrating the complex geometry. Since opto-electronics are non-invasive they constitute an important advance in the study of the kinematics of the spine.

The infratemporal fossa and its contents (particularly the pterygoid muscles) is a region difficult to explore, in spite of its importance in odontostomatological pathology. In order to reduce the indications that justify examination by computed tomography and magnetic resonance imaging, for reasons of economy of health, the authors describe by application of orientated anatomical slices the way in which ultrasonography can be performed. Only the posterior approach between the mandible laterally and the mastoid process medially provided consistently adequate exploration of the infratemporal fossa and the pterygoid muscles.

This work studied the development of the ventral part of Meckel's cartilage and its relationship to the morphogenesis of the mandible in a series of human fetuses. The development of the cartilage was followed up to the end of the embryonic period (stage 23, 8th week) when the primary ossification centre, which was formed from a condensation of embryonic mesenchyme, had become two bony plates forming a trough in which lay the neurovascular bundle. From this trough invagination of the bony plate formed the dental crypt. The primary ossification centre disappeared around the sixth month of fetal life.

According to the ultrasound and MRI findings, supported by planned dissections, the female perineum is organised around the musculofascial system converging towards the fibrous structure of the central perineal tendon (CPT). Behind the CPT the fascial layers form part of a fibrous assembly extending from the ventral surface of the sacrum to the anal complex, prolonging the direction of the sacral concavity downwards and forwards. On the other hand, in front of the CPT the fasciae fuse to form two aponeurotic bands circumscribing the urogenital fossa. The fascial system is reinforced cranially by the structures of the hypogastric sheath and the uterosacral ligaments. The weak point of the urogenital fossa is partly filled by the urethral-clitoridal-vulvar complex. The perineum so formed plays a cardinal role in stabilising the pelvic viscera. Stress is placed on the firmness of the posterior perineum, a key element in pelvic stability. The posterior perineum is often involved in pathological conditions and a good acquaintance with these structures is essential in defining therapeutic indications.

The authors have studied the relationship between anatomic and CT sections of the lateral pterygoid muscle in 39 anatomic specimens. Good superimposition of the images was found, which seems important in neoplastic invasion of the infratemporal fossa and which may lead to a pathogenic interpretation of the algo-dysfunctional syndrome of the masticatory apparatus.

Cette etude confirme que les sujets utilisant ce moyen de transport de charge doivent adopter une position adequate des vertebres cervicales, thoraciques et lombaires. Pour chaque sujet, on note une diminution significative de leur EISM thoracique et lombaire, mais les oscillations de la colonne vertebrale sont differentes suivant le niveau d'expertise des sujets. Par rapport aux sujets novices qui sont sensibles a la charge transportee, les sujets experts maintiennent un meilleur controle de leur nouvelle posture en diminuant les oscillations du tronc. Ce comportement postural des sujets experts peut etre explique par une reponse volontaire, consequence d'un developpement et d'un entrainement musculaire. Cette adaptation de la posture peut s'averer necessaire afin d'ameliorer la performance et la protection des epaules ainsi que de la colonne vertebrale lors d'un port de charge par sac-a-dos.

To determine the evolution of the diameter of the thoracic aorta with age in order to detect dilatation more reliably by imaging, we performed a retrospective analysis of the MRI examinations of the normal thoracic aorta of 66 subjects aged 44.1+/-19.1 years (range 19.1-82.4 years) obtained between 1991 and 2000 on a Magnetom SP 42 1T apparatus (Siemens) using T1-weighted spin echo sequences with electrocardiographic synchronization. Sixteen measurements were made in the axial plane, the oblique sagittal plane in the axis of the aortic arch, and the oblique frontal plane perpendicular to the latter at the level of the ascending aorta, the arch and the descending thoracic aorta. We found an increase in the thoracic aorta diameter and a significant relationship between this diameter and the age of our subjects, wherever the measure was performed. However, there was no systematic correlation between aortic diameter and age. The aortic diameter evolved with age and a marked difference seemed to exist in measurements made in groups younger and older than 40 years. This study, conducted on a small population of 66 patients, thus helps to define a normal aortic diameter, thereby making the diagnosis of pathological dilatation of the aorta more reliable.

The influence of various modes of carrying a load of 16 kg (15.69 DaN) on the static positioning of the pelvic girdle and the thoracic and lumbar segments of the spine was examined in seven male subjects. The displacement of cutaneous markers attached to easily palpable skeletal landmarks was recorded using 4 CCD cameras; the data acquired were analysed using an optoelectronic technique (SAGA3). The subjects stood upright on an AMTI biomechanical force platform, from which the ground reaction forces enabled displacements of the centre of gravity axis and thus the moment of the mass carried to be determined. The modes of load carriage examined were: 1) in a case in the left hand; 2) in a case in the right hand; 3) equally in two cases; 4) on the head; 5) in a rucksack; and 6) in an anterior bag. The results showed displacements of the pelvic girdle, the caudal and cranial lumbar segments, and the caudal and cranial thoracic segments in the three orthogonal planes (sagittal, frontal and transverse). The influence of the moment created by the load was seen in the statokinesigrams. The use of external markers using an optoelectronic technique, in association with the ground reaction forces, enables the mode of load carriage to be determined. The results show that the influence of the moment exerted by the mode of load carriage on the gravity axis has important ergonomic consequences.

This study presents a retrospective analysis of 15 portal vein CT scans, conducted for the evaluation of hepatic metastasis in patients suffering from colorectal cancer, with the aim of verifying in vivo the presence of laminar flow as reported by Pironcof. After selective catheterization of the superior mesenteric artery, CT scans were performed during opacification of the portal vein. Different flows were identified by the incomplete opacification they induced in the portal vein. Splenic flows could always be identified, however right colic and superior mesenteric flows were only seen in 3 cases (20%) and gastrocolic flow in 2 (13.6%). Even though incremental (i.e. slower than helical) the CT acquisitions allowed the flows to be viewed by modifying the visualisation window. In vivo evidence of laminar flow is provided which supports Pironcof’s experimental observations.

The motion of the thoracic and lumbar spine segments was analysed by mean of the skin landmarks method in 14 volunteers (7 males, 7 females). The results demonstrated that there was no significant difference between men and women and there was either facilitation or limitation of the motion of the characteristic landmarks of spinal segments during trunk motion in perpendicular planes. The mobility of spinal segments was associated with pelvic girdle motion in order to obtain the planned amplitude, and varied with hip joint abduction. The analysis of the precise mechanisms of relaxing or stretching of the pelvivertebral musculo-ligamentous structures constitutes a large field of investigation that necessitates the study of other lower limb postures and the use of robotic techniques.

The overall movement of the trunk is made up of two components, namely the movements of the pelvic girdle and the vertebrae. In the frontal plane, the amplitude of the pelvic movements appears to be relatively limited compared to the vertebral column whereas the pelvis makes the major contribution to the total rotational movement in the axial plane.

Optical techniques using single wavelength lasers allow precise study of the superficial displacements of deeper anatomical structures through direct mechanical pull. Two techniques have been used in this study: 1. Double exposure speckle photography. Since 1980 the relationship between the surface displacements and minimal traction applied to the transverse processes of the spine, either unilateral or bilateral, was studied in an attempt to simulate muscular action exerted at this level. 2. Computerised speckle interferometry. This allowed analysis of the deformations between the lumbar vertebrae under vertical compression, shear or torsion outside the usual anatomical planes. This preliminary study outlines the mechanical behaviour and the plasticity of the vertebral structures but has been performed on only a few anatomical specimens thus not allowing statistical analysis. This would require a larger series.

The urachus, derived partly from the allantoic canal, tethers the apex of the bladder to the umbilical ring. This vestigial structure, though constant in man, is formed by a whole series of embryologic mechanisms which are still controversial. Total or partial persistence of the lumen of the urachal canal, when sufficiently extensive, becomes manifested by characteristic clinical features. Moreover, it is frequently associated with malformational urogenital involvement, which must be routinely sought. The sole form of treatment consists of total surgical excision of the urachus.

Under static loading during weight-lifting, the lumbosacral spine essentially exhibits horizontalisation of the base of the sacrum (superior plateau of S1). We have attempted to elicit the mechanism of this horizontalisation by means of radiographs. These do not demonstrate any movements of the sacroiliac joints or plasticity of the hip bones. However, a symmetrical rotation of the hip joints conditions a retroversion of the pelvic girdle which explains the horizontalisation of the upper sacral plateau. This fixation of the block of the pelvic girdle is under muscular control, so that this mechanism can be improved by appropriate training.

The authors report 14 lymphoscintigraphies of the ovary, 8 before and 6 after the menopause. Injection of colloid labeled with technetium 99 m with elective lymphatic absorption was made into the mesovarium under laparoscopic control. Frontal and lateral images of the lymphatic drainage were made with a gamma camera 4–6 h after injection. Even in this short preliminary series, the premenopausal women showed major local and regional lymphatic circulation with drainage to the lumbo-aortic and pelvic nodes. After the menopause the lymphatic flow decreased and drainage was essentially by the aorto-lumbar nodes.

Ce travail global a permis d'observer des elements qui doivent etre analyses plus precisement par des investigations complementaires : - influence d'autres positions des art. coxo-femorales (adduction, rotations mediale ou laterale, flexion), ou des genoux (flexion), sur la cinematique de la colonne lombaire et thoracique ; - analyse opto-electronique des variations angulaires des capteurs au cours de la realisation d'un mouvement du tronc dans un plan anatomique ; - determination des mecanismes precis et des structures musculo-ligamentaires concernees par les techniques anatomiques, de comportement des materiaux et de robotique.

The authors investigated intracranial pressure, resistance to cerebrospinal fluid (CSF) absorption following ventricular infusion and radiopharmaceutical absorption of radionuclide injected into the ventricles in two infants with dilatation of the subarachnoid pericerebral space. The results of this study showed an increased resistance to CSF absorption. Intraspinal CSF absorption was seen to predominate, as shown by isotopic cisternography.

The first part of this paper deals with a description of the physiopathology of acute intestinal intussusception in infants. The second, experimental part of this work, describes the investigation of 15 autopsy specimens with a detailed examination of the anatomy of the ileocecal valve in three cases. The results of this study allow to identify several factors possibly involved in the pathogenesis of infantile intussusception. These factors include: anterior insertion of the terminal ileum with respect to the cecum; decreased rigidity of the colon due to the absence of the teniae coli; papillary arrangement of the ileocecal valve; and participation of the longitudinal muscle fibers of the colon in the constitution of the valve.

Right hemicolectomy was done in a three and a half month old infant presenting irreductible acute intestinal intussusception. Analysis of the anatomical specimen allowed confirmation of the authors' histological theory on the genesis of infantile intussusception. Histological study demonstrated the key elements of this theory: thickness of the cecal musculosa clearly less than that of the right colon, thereby accounting for the lesser resistance of the former; contribution to the outer longitudinal muscle fibers of the ileum and colon to the constitution of the ileocecal valve commissures. These longitudinal muscle fibers did not span across the base of the ileocecal valve.

The axillary lymphatics provide the main drainage system of a breast cancer, and the authors describe a method enabling them to obtain three-dimensional radio-anatomical images of the axillary lymph nodes. This method relies on a numerical analysis of data provided by stereotactic radiographs taken in a radiotherapy simulator and subsequently subjected to computer analysis. After setting up this system on anatomical specimens, the method was applied to lymphograms of the upper limb carried out during the investigation of patients with breast cancer. It was possible to identify to which lymphatic group 70% of the opacified nodes belonged and to locate the position of the 30% remaining. This approach is of particular interest to the radiotherapist when attempting to determine the radiation fields and dosage received by the target tissues.