’In consultation with another veterinary surgeon, two possible causes of this intense lameness were discussed:  one, that we had septic infection of the coronet, and that probably the swelling of this part would soften, and sloughs occur; the other, that a fracture of the os pedis or os coronae existed.  The enlargement of the coronet was hard and firm, not particularly sensitive.  It was decided to do nothing for a few days.  In a week the pain abated, and the mare would put her foot on the ground, and ceased to “nurse” the limb as she had done.  When moved over in the box she put a little weight on the foot, but limped very decidedly.

’Another week passed, and the pain and lameness further abated, but the swelling around the coronet continued.  Perhaps it was a little less in front, but it had not decreased on the inside.  It remained firm, and was not painful on pressure.  It showed no soft places, and the upper part of the leg remained free from oedema.

[Illustration:  FIG. 158.—­FRACTURE IN SITU (OS CORONAE).]

’The diagnosis was now that a fracture existed, and it was proposed to send the mare to grass for a few months.  The consulting veterinary surgeon suggested that before doing so a blister might be applied to the coronet.  This was done.  The mare was found next day again on three legs.  She had apparently been down during the night.  In a few days the coronet increased again in size, and within a week “broke out” in two places.

’The opinion now formed was that, with a fracture and this additional cause of inflammation around the joint, it would be most economical for the owner to have her killed.  This was done, and a post-mortem examination was made by Mr. Hunting and Mr. Willis.

[Illustration:  FIG. 159.—­WITH BROKEN PORTION REMOVED.]

’Post-mortem.—­The foot, cut off at the fetlock-joint, showed extensive swelling all round the coronet.  There were two wounds on the skin—­one on the front of the coronet, the other on the inner side.  From both pus and blood had escaped.  They both communicated under the skin with a large abscess cavity.  The abscess did not communicate with the joint.  The pastern bone was sound.  On separating the pastern from the coronet bone the articular surfaces were of a healthy colour, but the soft tissues immediately surrounding them were inflamed.  On the centre of the articular surface of the coronary bone a thin red ring was noticed, and the portion of cartilage within it seemed raised.  With the point of a scalpel this portion was lifted, and was found to be not only cartilage, but a layer of bone completely detached from the os coronae.  On removing the bones from the hoof the rest of the bone was quite normal, as was the pedal bone.

’Fig. 158 shows the articular surface of the coronet with the fracture in situ; and Fig. 159 the surface from which the broken portion is removed and laid to the side of the foot.