This hygroma usually results from blows with the ox-goad, which cause inflammation of the subcutaneous connective tissue and œdematous infiltration extending down the leg. Afterwards the slightest injury, or even the friction due to the animal lying down, causes liquid to collect and an hygroma to form.
Fig. 28.—Hygroma of the point of the sternum.
This hygroma is readily infected and often suppurates; it then becomes very sensitive, producing intense lameness. More frequently, however, under the influence of prompt treatment, the liquid is absorbed, the layers of subcutaneous connective tissue become hardened, and undergo more or less extensive induration.
HYGROMA OF THE POINT OF THE STERNUM.
Hygroma of the point of the sternum is a rarity. It only occurs in thin animals in which the point of the sternum is prominent, and which are confined to stables with rough floors and provided with insufficient bedding.
The swelling should not be opened, for the tissues in front of the sternum readily become the seat of suppuration.
If treatment is desirable, the fluid may be drained off by means of an aseptic puncture.