REGENERATION OF PERIPHERAL NERVES 481 



For about 10 mm. (in the adult rat) proximal to its entrance 

 into the peroneal muscles, the peroneal nerve normally gives off 

 no branches. This was the region selected for operation. 



Distal to the region of operation, the nerve gives off branches 

 to the peroneal muscles, the tibialis anterior, the extensor digi- 

 torum longus and also extends its fibers to the dorsum of the 

 foot. 



TECHNIQUE OF OPERATION 



The method of operation was as follows: The animal was 

 anesthetized, the nerve exposed by a cut about 1.5 cm. in length 

 through the skin, fascia and biceps muscle. The nerve was 

 lifted free from surrounding structures, crushed and wired or 

 simply wired. The flaps of this wound were then closed by 

 two or three stitches in the skin and the wound sealed by apply- 

 ing a bit of sterilized cotton covered with collodion. 



Crushing the nerve was accomplished by means of a small 

 pair of bone forceps, the blades of which had been polished off, 

 leaving instead of sharp cutting edges, blunt smooth edges. By 

 this means the bundles of white glistening nerve fibers were 

 divided, leaving the perineurium intact as a tube connecting the 

 divided ends of the nerve fibers. The space within the peri- 

 neurium, between the divided nerve fibers, usually filled with 

 serum or blood. This operation was followed in every case by 

 loss of ability to extend the toes properly and to rotate the foot 

 outward. Recovery was in most cases rapid and the repaired 

 nerve was usually free from interfering masses of connective 

 tissue. 



The difficulties in determining at the autopsy the exact point 

 of injury to the nerve and the importance of having this infor- 

 mation, later led to a modification of the simple crushing tech- 

 nique, as follows: At the point of crushing, a silver wire hook 

 was caught around the nerve and by means of a long narrow 

 nosed forceps this hook was forced to close tightly on the nerve. 

 The extended ends of the wire hook were then trimmed off, 

 leaving a small bit of wire doubled upon itself and holding be- 

 tween its two limbs the perineurium or a portion of it. The 



