The hock is a notoriously difficult structure to get an inside look at. With five joints, numerous bones, and multiple soft tissue structures contained in a relatively small area, pinpointing sometimes microscopic issues can be a challenge. But with more advanced technology comes a better chance of obtaining a clear picture of the hock, along with the issues that can impact it.
At the 2015 American Association of Equine Practitioners’ Convention, held Dec. 5-9 in Las Vegas, Myra Barrett, DVM, MS, Dipl. ACVR, shared the results of a study in which she examined the most common lower hock abnormalities identified on MRI exam. Barrett is an assistant professor of diagnostic imaging at the Colorado State University College of Veterinary Medicine & Biomedical Sciences, in Fort Collins.
Barrett said the hock is a complex structure with two upper and three lower joints. The distal (or lower) joints are subject to a number of injuries and issues that result in lameness. Common diagnostic options include radiography, ultrasound, and diagnostic analgesia, which, due to the hock’s aforementioned complex anatomy, all have limitations in successfully localizing and diagnosing the lameness.
“Ultrasound only allows us to look at soft tissues and with less resolution than MRI, in addition to the surface of bone,” Barrett explained. “Radiography requires more advanced bone damage before it’s detectable compared to MRI and is also limited by the superimposition of structures. Diagnostic analgesia doesn’t allow us to specifically pinpoint the source of pain, just gives us a general region.”
On the other hand