THE 
VETERINARIAN. 
VOL. IX, No. 104.] AUGUST 1836. [New Series, No. 44. 
ANIMAL PATHOLOGY. 
By Mr. Youatt. 
LECTURE VIII. 
Neurotomy. 
THE surgical anatomy of that portion of the fore leg of the 
horse which is concerned in neurotomy, and the proper mode of 
performing the operation, will be the subject of the present 
lecture. 
The Humeral Plexus . — A small branch of the fifth cervical 
nerve, much larger ones from the inferior fasciculus of the sixth 
cervical, the whole of the inferior fasciculus of the seventh, and 
the principal part of the first intercostal, or rather of the infe- 
rior branch of the first dorsal, and also various filaments from 
the sympathetic or great organic nerve, unite in order to form the 
humeral plexus. There is very considerable interlacement and 
intermingling of these various branches : but the plexus is again 
gradually divided into several nerves of considerable bulk, with 
two of which alone we have to do, the radial and the ulnar, and 
which are continued from the plexus to the extremity of the 
limb. 
The Radial Nerve arises from the plexus by two branches, 
which, united, adhere to and accompany the humeral artery 
along the back part of the radius to the knee. It there passes 
under the posterior annular ligament, and, still in company with 
the artery, pursues its course down the leg on the inner side, and 
along the edges of the flexor tendons. It here takes the name 
of the inner metacarpal nerve, which it retains until it arrives at 
the fetlock. At about one-third of the distance down the leg, 
a branch is sent obliquely and downward across the flexor tendons 
to anastomose with another nerve on the outside of the leg ; but 
the point from which this branch takes its origin, as well as the 
point of insertion into the opposite nerve, differ materially in 
different subjects ; and in some cases the insertion is so low as to 
VOL,. IX. 3 K 
