Muscle Injuries and Their Consequences (Pathophysiology)

Key Points:
• Muscle injuries, including injuries to the musculo-tendinous junctions are common in canine athletes, working dogs and active pet dogs
• The most common muscle injuries in active dogs affect the supraspinatus, teres major and iliopsoas muscles.
• The endomysium, perimysium and epimysium, which are critical to effective healing and remodeling of muscle, are specialized forms of fascia. Muscle cannot heal and regain full function if the fascia that encases the muscle components is not retained intact
• Muscles have their own stem cells, which are self- renewing and can differentiate into a wide variety of other cells for healing and complete regeneration of muscle. A variety of therapies to stimulate more effective and rapid muscle regeneration are under investigation.

Frequently the veterinary field has viewed the field of orthopedics as being mainly concerned with disorders and injuries of bone. For decades the field was occupied with studying and treating degenerative conditions such as hip dysplasia, osteochondrosis dissecans and panosteitis and injuries such as fractures and dislocations. However, with the increasing participation of dogs in a variety of sports and other physical activities as well as new, more sensitive diagnostic options available to veterinarians such as musculoskeletal ultrasound, there has been an increase in the prevalence of soft tissue injuries in dogs, particularly injuries involving muscles and tendons, and frequently the musculotendinous junction. Regardless of whether this increase is related to more injuries or better diagnostics (most likely it is a combination of the two), the result is that veterinarians who work with active dogs are thinking more deeply about issues such as how soft tissues like muscle respond to injury, what types of body movements lead to muscle injury, and how we can effect more complete and rapid healing of injured muscles.  [...]