BARLOW ON TENDINOUS STRUCTURES. 
259 
award the tendinous fibre that share of importance which he seems 
to think has not hitherto been ascribed to it, is the following: — some 
of the ginglymoid joints of the fore and hind extremities, in conse- 
quence of their conformation, are disposed to assume a state of 
extreme flexion or extension ; and this extreme in either direction 
is not entirely dependent upon muscular action either for its full 
promotion or maintenance. The state of flexion is that into which 
they are brought either under active movement, or by the recum- 
bent posture, and is imitated in the dead limb by separating from 
it all the muscles and tendons, leaving entire the lateral ligaments 
of the hock or elbow joints. Then bring the anterior surfaces 
of the humerus and radius, or tibia and large metatarsal bone, to- 
wards each other by flexing the elbow or hock, and, after the flex- 
ing power has brought the bones some way in this direction — after 
they have passed the medium between flexion and extension — they 
will, without any farther application of the same force, suddenly 
jerk into a state of the utmost flexion — a state which exists when 
the horse is leaping, as well as when he is in a recumbent posture. 
The state of extension, on the other hand, is that more especially 
found when the horse is standing ; and the tendency of the elbow 
or hock joints to attain this may be seen by bending back the bones 
alluded to, when, having. passed again the medium between flexion 
and extension, they will spring into a state of the greatest extension. 
Flexion and extension of one joint are so materially dependent 
upon corresponding actions of other joints in the same limb, that, if 
in addition to retaining the lateral ligaments of the elbow, we pre- 
serve all the bones of the extremity attached to each other, and 
retain the tendinous structure of the flexor brachii from its origin 
to its insertion into the head of the radius, with its continuation 
along the extensor magnus, preserving at the same time, all other 
tendinous and ligamentous structures in connexion with the limb, 
and remove, as far as possible, all muscular ones, we find, on 
placing the foot on the ground in a standing position, that weight 
applied so as to fall through the scapula and humerus upon the 
bony pillar formed by the radius, ulna, carpus, and metacarpus 
upon the foot will not cause flexion, but will be supported. 
The same thing is exemplified in the hind extremity, by preserv- 
ing entire the ligaments of the limb, and the tendons of the gastroc- 
nemii, flexor metatarsi, and extensor pedis muscles. Weight, then, 
applied vertically from the os femoris to the foot will not produce 
flexion of the foot. The joints are thus retained in a state of 
flexion or extension, as the case may be, without muscular power 
being applied directly to them, and the state of their passive ex- 
tension, (that position of the extremities when a horse is standing) 
should surely be considered worthy of some notice, in endeavour- 
