VN June 2021

Vetnuus | Junie 2021 28 Before answering the question of the function of dewclaws, it is necessary to define what is meant when referring to a dewclaw. A dewclaw is a rudimentary or vestigial digit on the medial aspect of front and hind paws. In the hind paws of dogs the dewclaw is frequently only attached by a piece of skin. No bone or tendon remains indicating that whatever use it may have had is no longer required. These remnants are frequently removed. In cats the dewclaw of the front limb is not rudimentary but is used during hunting to catch and hold prey. It is also used to assist when climbing trees. In dogs the front limb dewclaw has numerous tendons attached to it. Tendons are attached to muscles, implying that these digits may have a function. In certain herding breeds the dewclaws are used when navigating snowy terrain. There is debate as to whether or not the dewclaw helps dogs to gain traction when they run. Dewclaws may even be used to hold bones or other prey items as the dog chews, bites or pulls with its teeth. When considering the anatomy of the carpal region, the tendons attached to the dewclaw feed into the connective tissue that surrounds the dorsal aspect of the joint. On the palmar aspect there is an intricate network of tendons, ligaments and retinaculum that also support the joint. I have observed sporting dogs. In the accompanying photographs notice how the carpus hyperextends during high impact motion, and when the dog is running. In this situation, the dewclaw touches the ground. Dr. Christine Zink, a world-renowned canine sports and rehabilitation specialist, suggests that the function of the dewclaw is to prevent torque on the leg. Dewclaws – Do they have a Function? Tanya Grantham