AS CONNECTED WITH MUSCULAR FIBRE. 
557 
the metacarpi magnus. It is a band proceeding from bone to 
bone, though, in its course, it is connected with fleshy fibre and 
with the tendons of muscles. When the animal is erect it sup- 
ports the scapula. When the horse lies down, it, conjointly with 
the brachial fascia, prevents traction upon the contractile substance 
of the extensor magnus. To its use in associating the action of 
the two muscles I have no space to allude ; but its importance in 
this respect is obvious and fully acknowledged. 
I must be understood to assert, that there is a continuous band 
of ligamentous structure extending over the anterior of the limb 
from the point of the shoulder in a direct line to the inferior of 
the carpal joint. This substance, though destined for important 
service, is of comparative small size, and I cannot but think it is 
frequently subjected to injury. I have seen horses, said to be 
lame in the shoulder, drag the fore-leg upon the ground, refusing 
either to flex the radius upon the humerus or to advance the cannon. 
Such is exactly the action any one acquainted with the uses of the 
muscles I have referred to would anticipate, if the ligamentous 
band which connects them were sprained; and the seat of injury 
in these cases, I anticipate, will be found to exist not in the 
shoulder, but in the connecting tendon, or where the arm unites 
with the shoulder ; for as, at other parts, the tendons blend with 
and strengthen the band, this becomes the weakest point. 
The other extensors of the limb are similarly protected against 
the possibility of traction by the intervention of white fibrous 
tissue. The brachial fascia, of great density, takes its origin from 
the outer side of the humerus, below the external trochanter, and, 
passing over the superior part of the body of the extensor pedis, 
blends with the tendon of the muscle. Nor is this all : from the 
posterior of the trapezium a ligamentous slip of considerable size 
takes its origin, and, proceeding obliquely downwards and for- 
wards to unite with the tendons of the pedis and suffraginis, resists 
any traction upon the muscles during the flexion of the pastern, 
while at the pastern itself further protection is afforded by union 
with the ligaments of the joints, and blending with the lateral 
continuations of the suspensory ligament. 
The provisions to which I have alluded are designed to prevent 
the muscular contractility being excited by traction resulting from 
mechanical force, or from the flexion of the limb. When the 
knee is bent, the space measured from the head of the radius to 
the coronary process of the os pedis is increased about four inches. 
Were there no provision of a special kind made against such a 
possibility, the muscular substance would have been subjected to 
a traction of this extent every time the limb was fully flexed. To 
prevent such an occurrence, the brachial fascia attached to the 
VOL. XIX. 4 G 
