Front-Leg Paralysis in a Dog

Paralysis in one front leg is called monoplegia. The paralysis may cause your dog to drag its leg, or to stop moving around completely. According to Scott Alan McKay, DVM, of the Pet Education website, the reason for front-leg paralysis is usually an injury to the radial nerve, which causes the dog to drag its leg along the ground or lift it up and stop using it.

  1. Radial Nerve

    • The radial nerve begins in the brachial plexus, which is a bundle of nerves located under the upper front leg that originates in the spinal cord in the dog's neck and ends in the paw. The radial nerve makes it possible for the dog to move its leg, bend it at the elbow and wrist and flex the toes. The nerve runs down the inside of the dog's upper leg, then passes around to the front for the lower half where it provides sensation to the outside and front of the leg. It is a large nerve, with nerve fibers encased in a protective sheath.

    Radial Nerve Injuries

    • An injury to the paw can result in damage to the radial nerve. Trauma is the most common injury, and depending on the severity of the trauma, the dog may suffer one of three levels of damage. Neurapraxia is a temporary loss of the nerve function and usually heals on its own; axonotmesis is damage to some of the nerve fibers while leaving others intact; and neurotmesis is complete severance of the nerve, with damage to both the nerve fibers and their protective covering. This frequently happens if the dog is hit by a car or jumps or falls from a height of six feet or more.

    Radial Nerve Paralysis

    • Injury to the radial nerve will affect the way the dog uses the damaged leg. Minimal or moderate damage to the nerve may result in temporary paralysis of the front leg, but the dog has a good chance of recovering the use of its leg once the nerve damage heals. Neurotmesis, or serious damage to all parts of the radial nerve, causes loss of feeling in the front leg and results in long-term paralysis and loss of use.

    Treatment and Prognosis

    • The most important aspect of treating a radial nerve injury is to protect the dog's leg from further damage while it heals. Dragging the paw along the ground can increase the injury and may cause damage to the paw itself. Once the nerves begin to heal, the dog may feel some pain in the leg and start licking or chewing itself, causing more damage. If the leg is not used, the muscles will start to atrophy within a few days and the dog will need physical therapy to regain muscle tone and strength in the leg. If a dog loses all use of the leg, the veterinarian may recommend amputation of the leg to prevent complications once it begins to atrophy.