DISEASES OF THE LEG. 
699 
C. DISEASES OF THE LOWER THIGH OB LEO. 
The thigh, especially in the horse, is surrounded by a tense, stretched skin, 
which on the external face is strong, but on the internal quite thin. Towards 
the front of the internal surface of the thigh, the skin and slightly-developed 
subcutis lie directly in contact with the tibia, which, therefore, at this point 
is particularly exposed to injury. About three-quarters of the bone, i.e., the 
entire external and the posterior portion of the internal surfaces, are covered 
with muscles which are singly clothed with fasciae, and are again surrounded 
by the fascia lata. The latter arises from the .muscles of the quarter and 
upper parts of the thigh, and is partly inserted into the crest of the tibia, 
partly extends below the hock, to become continuous with the fascia covering 
the tendon of the extensor pedis. In consequence of this formation, injuries 
to the leg present certain marked peculiarities. 
I—WOUNDS AND INJURIES. 
Injuries of the tibia are commonest in horses, and are caused by 
kicks, and by the leg being passed over bales or over the carriage-pole. 
Sometimes the skin alone is inflamed, or extensively torn, but not 
infrequently the periosteum and even the bone are bruised. The 
bone is sometimes fissured by kicks, a condition which will later 
receive attention; or diffuse periostitis is caused, though it also follows 
bruising of the periosteum, without the bone itself being injured. 
Periostitis of the tibia produces well-marked swinging-leg lameness 
and shortening of the forward stride, while the thigh is moved slowly 
and stiffly. It usually lasts three to four weeks, and is succeeded by 
thickening about the tibia. The local pain shown on palpation prevents 
any mistake in diagnosis. Injuries of the tibia itself can usually be 
detected by probing. 
The presence of strong fascia covering the muscles of this region 
causes wounds, which would otherwise heal without trouble, to be 
followed by very dangerous consequences. Injury to the fascia is 
troublesome, because the muscular tissue protrudes through the rent 
(muscular hernia), and being irritated by its edges, commences to pro¬ 
liferate actively;—or suppuration may lead to necrosis of fascia, and, 
before the necrotic portions can be shed, excessive fungous granulations, 
the growth of which is favoured by the continuous movement of the 
muscle, arise and greatly impede healing. This condition is commonest 
on the lower portions of the biceps femoris muscle, but may occur in 
any region of the tibia. 
A second difficulty in the healing of such wounds is the development 
of subfascial cellulitis. It generally accompanies perforating wounds 
caused by stable-forks. The symptoms are great pain when the animal 
stands on the limb or attempts to move it, moderate swelling, inflamma¬ 
tion of the neighbouring lymph vessels and glands, and fever. The 
