No abstract

No abstract

A stress fracture of the scaphoid combined with distal radial epiphysiolysis occurred in a 16 year old badminton player. Repeated shearing and torsional forces by excessive wrist movement from hitting a shuttle probably cause stress injuries in both the scaphoid and the distal radius. (BrJ7 Sports Med 1997;31:256-257) Keywords: stress fracture; scaphoid; distal radial epiphysis; badminton Stress fractures of the lower extremity are common and are being seen more often in athletic activities,' but those of the upper extremity are uncommon. To our knowledge there are only two published reports of stress fractures of the carpal scaphoid.' ' We report a further case of such a fracture combined with distal radial epiphysiolysis.Case report A 16 year old boy came to our clinic with diffuse pain around the right dominant wrist. He had practised badminton for three hours a day, six days a week, for the past two years. Seven weeks before his clinic visit he began to have pain in the wrist, which worsened with hitting a shuttle and improved with rest. Figure 1 Initial posteroanterior radiograph shows slightly increased bone density at the waist of the scaphoid and widening of the radial aspect of the distal radial epiphysis.Initially, he thought that he had strained a muscle and treated it conservatively by applying ice and decreasing his activity level, but there was little improvement. There was no previous history of pain or injury to the affected wrist.On physical examination the patient had tenderness over the distal radius and into the anatomical snuff box with diffuse swelling. He could actively move the wrist through a nearly full range of motion, but a forced passive dorsiflexion and volarflexion of the wrist caused increased pain over the wrist joint. A posteroanterior radiograph of the right wrist showed slightly increased bone density at the waist of the scaphoid and widening of the radial aspect of the distal radial epiphysis (fig 1). A semipronated oblique view showed a non-displaced fracture through the waist of the scaphoid with sclerotic borders and widening of the distal radial epiphysis, particularly on its radiovolar aspect (fig 2). The right wrist was immobilised in a short thumb-spica cast for eight weeks. Subsequent radiographs showed complete healing of the scaphoid fracture and a return to almost normal in both the width and the hazi- Figure 2 A semipronated oblique view shows a transverse fracture through the waist of the scaphoid with sclerotic borders and widening of the distal radial epiphysis on its radiovolar aspect.

No abstract

The viscoelastic properties of four-armed, star-shaped polystyrenes having narrow molecular weight distributions were studied in a undiluted state by the tensile stress relaxation method. The steady-flow viscosity, the steady-state compliance and other rheological parameters were determined from the relaxation modulus master curves. The molecular weight dependences of these parameters were compared with those of linear and comb-shaped polymers. KEY WORDS Star-Shaped Polymer I Branched Polymer I Stress Relaxation I Steady-Flow Viscosity I Steady-State Compliance I Entanglement I