Muscle is a soft tissue found in most animals. It is a band or bundle of fibrous tissue in a human or animal body that has the ability to contract, producing movement in or maintaining the position of parts of the body.
Muscles are responsible for movement of the body as well as body support. Tendons are tough fibrous tissue that connect the muscles to the bones. Ligaments are very strong and attach one bone to another. Damage to any of these can result in significant swelling, pain or inability to use that part of the body.
A normal muscle can be stretched, pinched, or injured directly, resulting in fiber disruption, weakening, and immediate or delayed separation of the uninjured portions. A muscle disruption can be caused by normal activity or the muscle structure may be compromised by systemic or iatrogenic (physician-caused) conditions.
A rupture is a soft tissue injury where the muscle belly, tendon or ligament is completely torn in two. The rupture may be complete or incomplete, and may be in the middle of the muscle or at the muscle-tendon junction. The acute (sudden and severe) stage is characterized by a typical inflammatory reaction that becomes chronic over time, with cross-linking, and adhesion development over time. Frequently, the acute phase is overlooked, as the signs may be temporary and respond well to rest. The chronic effects are often progressive and unresponsive to support therapies.
Limb and chewing muscles are among the most affected muscles. Muscle rupture that is not caused by a trauma is mostly seen in middle to old age working dogs.
Common signs and symptoms of muscle injury include
Immediate lameness that is characterized by the specific muscle affected
Localized swelling, heat, and pain
Generally present for a few days to a week
Chronic phase (if it develops)
Usually associated with scar tissue that impedes normal function of an extremity