MEDIAN NEURECTOMY. 
619 
and to protrude between the lips of the incision in the aponeurosis. 
When the nerve does not appear, it is usually sufficient to slightly alter 
the position of the limb. The most serious difficulty to be feared is from 
injury to the veins in this neighbourhood, and every care must be taken 
to avoid such a complication. 
In certain animals operation is rendered difficult by an abnormal 
arrangement of the radial veins, but this is rare. 
Peters, and after him others, showed that division of the median nerve 
alone may remove lameness resulting from bilateral lesions—that is to 
say, occupying both sides of one of the lower parts of the leg, or encir¬ 
cling these regions. The results are explained by the preponderating 
influence of the median nerve in the innervation of structures below the 
Fig. -238—Median neurectomy (semi-diagrammatic). N, Median nerve ; A, posterior radial 
artery ; V, one of the post-radial veins. 
knee, a preponderance due to the fact that at a variable point in the 
fore arm the nerve terminates by dividing into two branches, one of which 
is continued as the internal plantar nerve, while the other joins the ulnar 
at the upper border of the pisiform bone, beneath the tendon of the 
middle flexor, and is continued as the external plantar nerve. 
Cadiot and others have seen horses with various chronic affections, 
like strained tendons, splints, cartilaginous ring-bones, and periostitis of 
the phalanges, in which lameness has been removed, or certainly 
diminished, by dividing the median nerve. 
But others occur in which section of the nerve fails to remove lameness 
caused by lesions on the outer side of the limb, or at times even on the 
inner. The persistence of pain and lameness in the latter case is 
explained by the existence of recurrent fibres. Under such circumstances, 
