THE NERVES 139 



Leaving the interval between the two divisions of the scalenus, the 

 plexus passes to the inner aspect of the shoulder joint, and is found in 

 the axillary space, where a most intricate network is found surrounded 

 by a quantity of loose areolar tissue. 



Paralysis of the Brachial Plexus 



Cases of Paralysis of the Brachial Plexus have been frequently 

 recorded. The causes vary considerably. Occasionally it is due to the 

 presence of a tumour in the cranial cavity and consequent pressure on 

 the brain. 



A pecuhar case is recorded by Dollar as having occurred at the 

 cHnique at Alfort. " A horse was cast and kept down for a long time. 

 On rising it showed complete paralysis of one fore limb. Post mortem 

 examination showed that the brachial plexus had been bruised and 

 paralysed by a bony tumour on the second rib." 



Profuse haemorrhage into the axillary space may also bring about 

 paralysis owing to the pressure of the extravasated blood on the plexus. 

 Cases of temporary paralysis have also been attributed to shocks from 

 electric currents, and lightning strokes. 



Since the whole of the nerve-supply to the limb comes from the 

 plexus, when the latter is paralysed there is entire loss of voluntary 

 muscular movement. Very little can be done other than to apply 

 massage and mild counter-irritants to the muscles, to prevent atrophy. 



The Nerve to the Serratus Magnus, Superior Thoracic Nerve 

 OR Respiratory Nerve of Bell 



Contributory branches to this nerve are given off by the seventh and 

 eighth cervical roots respectively. The two branches pierce the upper 

 division of the scalenus muscle and then unite, and the nerve thus formed 

 takes a horizontal course backwards on the outer aspect of the thorax. 



