The purpose of this research was to clarify the causes of numbness and pain by traction of the upper limbs. We stretched the nerves in the upper limbs of rats by utilizing the flail of the shoulder girdle, and measured the blood flow of the brachial plexus and the median nerve. The model animals,32 wistar rats, were inserted with steel lines to the radius and ulna. These steel lines were drawn in the direction of a shoulder abduction of 80 degrees. A decrease and recovery of the blood flow were measured using the hydrogen gas clearance method.
The blood flow of the subepineural space in the brachial plexus decreases sharply in conditions with looseness of the plexus.
The blood flow of the intrafuniculuse in the brachial plexus decreases like a straight line in those states without looseness of the plexus. The blood flow of the subepineural space in the median nerve decrease like a straight line, too. The decrease rate of the subepineural space was sharper than that of the intrafuniculuse. As for the recovery rate, there was no significant difference in either site.
One of the factor that causes nervous and functional imbalance with a slight traction is a sharp reduction of the blood flow in the subepineural space of the brachial plexus.
