538 
DISEASES OF THE KNEE. 
fasciae of the fore arm; extensive counter-openings are therefore at 
times necessary. The radius is sometimes injured just above the knee. 
In this case also it is important to provide for drainage, either by counter¬ 
incision, drainage-tubes, or setons. Slight swelling with great pain points 
to disease of the bone (periostitis or necrosis), a complication which may 
occur at any time before pus formation has completely ceased. 
In horses, the inner surface of the elbow-joint may be injured by 
straddling across bales, poles, or similar objects. The pain is often so 
acute that the animals are unable to place weight on the limb. In these 
cases the median nerve is bruised; and although the effect of the 
injury may only last a few minutes, it may also continue for a couple of 
days. The pathognomonic symptom is insensibility below the elbow- 
joint, especially at the posterior surface of the limb. The affection soon 
disappears. 
Bassi in a mule saw movements of the left fore foot simulating string- 
halt. The front foot was lifted unusually high, and the animal often 
stumbled ; the symptoms were particularly noticeable when the animal 
moved backwards. On the external surface of the fore arm, just below 
the elbow, was a thickening, the result of a fall; it was not inflamed, 
and had existed for some weeks. The difficulty in movement had first 
appeared twelve to fifteen days after the fall. Permanent recovery fol¬ 
lowed division of the flexor metacarpi externus. 
G. DISEASES OF THE KNEE. 
Anatomy. The knee, a complicated joint, consists of three portions,— 
(1) The radio-carpal articulation. 
(2) The intercarpal articulation. 
(3) The carpo-metacarpal articulation. 
The first two are incomplete ginglymoid joints, because, in addition to flexion 
and extension, they allow of slight lateral movement, and, in the flexed position, 
of some amount of rotation, most marked in carnivora. The lower row of 
bones forms with the metacarpus an arthrodial joint, the movement of which, 
in all animals except carnivora, is exceedingly limited. 
Each of these three joints is surrounded by its own synovial membrane, 
though the lower is connected with the middle by a narrow slit. The common 
capsular ligament arises from the radius, is applied to both rows, and ends on 
the metacarpus. Two strong lateral ligaments attach the radius to the meta¬ 
carpus, while the bones of the carpus itself are united to one another and to 
the radius and metacarpus by interosseous ligaments which limit the movement 
of the knee-joint. 
The fascia covering the carpus and metacarpus, which is an extension of 
the deep portion of the fascia of the fore arm, forms, on the anterior surface 
of the knee-joint, sheaths for the extensor tendons, and is in close connection 
with the capsule of the joint. On the outer surface of the carpus the fascia 
becomes continuous with the ligaments of the joint, with the periosteum of 
the external surface of the pisiform bone, with the tendon of the flexor meta¬ 
carpi externus, and with the extensor pedis. On the inner side of the carpus 
