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Biomedical subjects

P Blaimont

Publications and source records attributed to P Blaimont.

At least 19 recordsLinked to original sources
PubMed2005

[Displacement of the instantaneous center of rotation of the humeral head during abduction: implication for scapulohumeral muscular function].

PURPOSE OF THE STUDY: To date, studies of glenohumeral stress forces have been based on the notion of a unique center of rotation situated at the geometric center of the humeral head. Early work, e.g. Fisher et al in 1977, suggested that the instantaneous center of rotation can migrate during abduction producing muscle vectors with variable moments and consequently variable stress forces. We conducted a kinematic analysis of the shoulder forces during continuous movement. MATERIAL AND METHODS: An imaging device commonly used for angiography enabled acquisition of one image per second during a continuous movement of abduction. Images were obtained for twenty healthy shoulders in ten subjects. RESULTS: The instantaneous center of rotation was not situated at the geometric center of the humeral head. Although interindividual variability was significant, the preferential positions of the instantaneous center of rotation implied a constant reproducible succession of gliding, rolling, and translation in variable proportions during the abduction movement. When the same movement was performed with a 3500g load held in the hand, the ICR migrated towards the upper part of the humeral head implying a predominance of the rolling motion over the gliding and translation motions. Between 40 degrees and 60 degrees glenohumeral abduction, the instantaneous center of rotation exhibited a metaphyseal displacement producing a longer lever arm for the supaspinatus and an abduction function for the infraspinatus and the subscapularis, unrecognized to date. After 60 degrees, medialization of the instantaneous center of rotation lengthened the lever arm of the deltoid. DISCUSSION: A valid analysis of the glenohumeral stress forces must take into consideration the localization of the instantaneous center of rotation. In the clinical setting, our findings demonstrate that the infraspinatus and the subscapularis play an important role which must be considered both in surgery and in rehabilitation.

Adult↗
PubMed1996

Contribution to the vascular origin of the unicameral bone cyst.

Vascular occlusion between bone cyst and intramedullary venous system seems to be the primum movens in the genesis of a unicameral bone cyst. High speed injection of saline and alternative aspiration injection of the cyst fluid and reaming of the medullary cavity clearly open vascular channels connecting the bone cyst to the intramedullary venous system. This was monitored by pre- and postmanipulative radiographs. This technique was employed in 12 patients with a unicameral bone cyst. All but one went on to healing with increasing diameter of the cortical bone and filling of the cystic cavity.

Adolescent↗
PubMed1990

[Reflections on the anterior cruciate ligament (A.C.L.) and clinical implications].

This report documents experiments on the front, crossed ligament undertaken after dissection of 17 human knees. The form, direction, constitution, and even the various diameters and tibial and femoral bone insertion surfaces of the ligament were all studied. Various cross-section experiments were undertaken to reveal the physio-pathological aspects. Greater tibial insertion area and diameter along with a more oblique orthogonal projection on the tibial correspond to the need to better spread the constraints. It is concluded that varying degrees of tension in function of the position of the knee, and knowledge of the various lengths and diameters of the ligament permit a better understanding of the prosthetic replacement surgery required.

Aged↗
PubMed1988

[Medial tibial pain in runners].

Pain at the site of the tibial insertion of the flexor digitorum longus and the soleus near the middle third of the medial border of the tibia may be encountered in young athletes, who have usually started to run in late adolescence. Heel valgus, abnormal mid-foot pronation and excessive tibial torsion may be seen in association. The symptoms are brought on after excessive training. Radiographs may show cortical thickening at the site of the pain, and a bone scan may demonstrate a mild increase in the uptake of the isotope at this site. The pain appears to be related to a strain of the attachment of the flexor digitorum longus and the aponeurotic insertion of the soleus into the tibia. The pressure in the deep posterior compartment of the tibia is normal. Histological examination of specimens from the flexor digitorum longus may demonstrate ischaemic changes in the muscle. Treatment is based on an understanding of the biomechanics of the foot in running, modification of training methods and the use of suitable orthotics. If these measures fail, partial division of the aponeurotic attachment of soleus and freeing of the insertion of the flexor digitorum longus is usually successful.

Adolescent↗
PubMed1982

[Biomechanical study of the ankle joint].

The authors have studied the transmission of body weight in several positions. Two methods have been used - strain gauges and injection of dye into the joint capsules to show areas with contact during weight-bearing and non weight-bearing. The findings have shown the role of the fibula and of both malleoli during weight-bearing which causes a noticeable increase in the area of surface contact. The lateral aspect of the talus and the medial aspect of the lateral malleolus are always in contact in any position of the talus. The fundamental role of the tibio-fibular ligaments in the mechanics of the ankle is demonstrated.

Ankle Joint↗
PubMed1979

[A case of melorheostosis. Clinical, radiological, pathological and biomechanical details].

A patient with melorheostosis of the right lower limb is described with the clinical findings and radiographic appearances which include angiographs and microradiographs. Tissue was taken from the knee joint at the time of arthrodesis and examined by histological, histochemical and biomechanical techniques. It is concluded that the bone in melorheostosis is not different from normal bone.

Adolescent↗