Curb and Curby Hocks in Horses
by Robert N. Oglesby DVM

The traditional meaning of curb is a swelling or enlargement of the back (plantar) aspect of the hind leg just starting at the bottom of the hock (see image below). This is best seen when viewing the horse from the side and gives a smooth convex outline where the horse is normally straight in this region. It may or may not be accompanied with lameness. The term "curby" is heard, which is often a horse with sickle-hock conformation that cause a convex appearance to this region. Curby conformation can predispose to curb but horses with normal conformation develop curb also.

In the past the enlargement was diagnosed as a inflammation and thickening of the long plantar ligament which runs down the back of the hock. However, the distal flexor tendons traverse this area and lie over the plantar ligament. All of this overlies the bones in the back of this region of the hock. Also the proximal splint bones, and their associated ligaments, lie to each side of this region with the proximal origin of the suspensory and its associated check ligament between them. Not surprisingly careful radiographic and ultrasound examination of a large number of curbs finds this is really a complex of different soft tissue injuries and bony enlargements of this region of the hock.

So curb is not a diagnosis but a description of a particular swelling with several causes and with other diseases resembling it. Only careful examination will reveal the true disease present and the treatment and prognosis will be based on the particular disease present and the severity of the lesions. This article deals with correctly identifying the appearance of curb, correctly diagnosing the cause, and the treatment and prognosis of each.