[Features of the structure of the metacarpal bones of athletes in different specialties]

Metacarpal bones have been examined in hand X-ray photos of 125 sportsmen at the age of 17-18 years who go in for swimming (dynamic loading on the hand) and competitive gymnastics (static loading on the hand). Under the effect of systematic trainings, which are connected with an increased loading on the hand, a number of morphological changes take place in the metacarpal bones. A prolonged loading of the dynamic character delays the synostosis process in the distal parts of the forearm bones and contributes to lengthening the I, III and IV and to widening the I-V metacarpal bones. As demonstrate decreasing indices of compactness in the swimmers, the widening diaphisis of the metacarpal bones occurs at the expense of dilatation of the medullary cavity. The static loadings result in a greater delay of the synostosis processes in the upper extremity parts mentioned, in a greater width of the I-III, V metacarpal bones in boy-gymnasts. The increased index of compactness demonstrates that the widening diaphysis of the metacarpal bones takes place at the expense of thickening of the compact substance and narrowing of the medullary cavity.