Biceps Muscle Injury of the Forelimb in Dogs (Injury to the M. biceps brachii)

  • Occurrence: common
  • Location of disease: Legs
Author: Dr. med. vet. Gisa Löwe | Last modified: 03.08.2026
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When to visit the vet?

Non-urgent see a veterinarian within 2–3 days

?

If the condition worsens / symptoms persist, consult a veterinarian.

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Definition

An injury to the M. biceps brachii in dogs is damage to the biceps muscle, which is located in the foreleg and attached to the shoulder joint. This injury can range from a mild strain to a complete tear.

The most important facts at a glance

The biceps brachii muscle is an important muscle in dogs, responsible for flexing the elbow joint and stabilizing the shoulder joint. Injuries to this muscle can result from overuse, sudden movements, traumas, or degenerative changes. Athletically active dogs are often affected. Symptoms of an injury include lameness, shoulder pain, and difficulty extending the leg. The diagnosis is made through clinical examinations, imaging techniques such as ultrasound or MRI, and possibly arthroscopy.

The treatment depends on the severity of the injury. Mild strains can be treated conservatively with rest and physiotherapy, while more severe injuries may require surgery. Strict aftercare with controlled increase in activity is crucial for a successful recovery. Prognoses vary depending on the severity and treatment, but with the right care, many dogs can regain their function. Long-term complications are possible if the injury is not treated in time.

Preventive measures such as regular training to strengthen the muscles and a balanced diet play an important role in minimizing the risk of injury. Overweight should be avoided, as it puts additional strain on the joints. A gradual increase in physical activity and regular veterinary check-ups can also help prevent injuries. Research in this field aims to further understand the underlying causes and develop more effective treatment strategies.

Causes

The M. biceps brachii is an important muscle that runs along the front of the upper arm. It plays a crucial role in flexing the elbow joint and stabilizing the shoulder joint. Anatomically, the muscle consists of long muscle fibers and a tendon that is attached to the shoulder joint. This tendon runs through a groove in the humerus, making it susceptible to injury.

In dogs, an injury to the biceps brachii muscle can occur due to various causes. One of the most common causes is overuse of the muscle, which can occur in athletically active dogs or those participating in agility competitions. In addition, sudden, violent movements or a trauma, such as a fall or impact, can lead to damage.

Other causes can be degenerative changes that occur with age, or inflammatory processes such as bicipital tenosynovitis. A genetic predisposition may also play a role in certain breeds, as some dogs are more susceptible to tendon injuries. Overweight and lack of conditioning can also increase the risk.

Symptoms

Rare symptoms:

The symptoms of a biceps brachii muscle injury in dogs vary depending on the severity of the injury. With a mild strain, the dog may only experience mild pain and show slight lameness. This lameness is often intermittent and can worsen after activity.

In more severe injuries, such as a partial or complete tear of the tendon, the dog usually shows significant Lameness of the affected foreleg. The animal may relieve the affected leg and have difficulty getting up or jumping. Swelling in the area of the shoulder and upper arm may also occur.

Another sign may be reduced muscle mass in the affected area, which results from the Protective posture / guarding posture of the dog over a longer period of time. The dog may also be sensitive to pressure in the area of the shoulder joint.

Therapy

The treatment for a biceps brachii muscle injury depends on the severity of the injury. For mild strains, conservative treatment with rest, anti-inflammatory medications, and physiotherapy may be sufficient. The dog should be kept on a leash for several weeks and physical activities should be restricted to allow for complete healing.

For more severe injuries, especially a partial or complete tendon tear, surgery may be necessary. The surgery aims to repair or reconstruct the tendon. After the operation, strict aftercare is required, including rest and a gradual increase in movement activities. Physiotherapy can help improve mobility and muscle strength.

In addition, alternative therapies such as laser therapy or acupuncture can be used to promote healing and relieve pain. The use of nutritional supplements containing glucosamine and chondroitin can also be helpful.

Prognosis and follow-up care

The prognosis for dogs with an injury to the M. biceps brachii varies depending on the severity of the injury and the treatment chosen. In mild injuries, the prognosis is usually good if the dog is treated appropriately and activity is restricted during the healing phase.

For more severe injuries requiring surgical intervention, the prognosis depends on factors such as the dog’s age, general health, and rehabilitation after surgery. With appropriate postoperative care and rehabilitation, many dogs can regain good to very good function of the affected leg.

Long-term complications are possible, especially if the injury is not recognized or treated early. These can include permanent Lameness or reduced joint mobility. Regular follow-up with the veterinarian is important to monitor the healing progress.

Prevention

Preventive measures are crucial in minimizing the risk of M. biceps brachii injury. Good physical conditioning is crucial, especially for athletically active dogs. Regular training aimed at strengthening the muscles and improving flexibility can reduce the risk of injury.

A balanced diet that supports the dog’s ideal weight is also important, as Overweight increases the stress on the joints and muscles. Feeding food rich in omega-3 fatty acids, glucosamine and chondroitin can promote joint health.

It is important to avoid sudden, excessive physical exertion, especially in dogs that are not trained regularly. A gradual increase in the intensity and duration of activities can help prevent injuries. Regular veterinary check-ups can help detect early signs of muscle or joint problems and treat them in time.

Outlook on current research

In practice, injury to the M. biceps brachii in dogs usually does not affect the muscle belly itself, but primarily the biceps tendon in the shoulder joint. Typical signs are chronic forelimb Lameness, Pain on shoulder extension, and exercise intolerance. The key point for the research outlook is therefore: this injury is increasingly understood today as a functional shoulder disorder that is often associated with additional problems such as supraspinatus disease or other shoulder lesions and should not be viewed in isolation. (pubmed.ncbi.nlm.nih.gov, pubmed.ncbi.nlm.nih.gov)

A key area of research is more precise diagnostics. In addition to the clinical examination, ultrasound, MRI, and arthroscopy are becoming increasingly important because they can better detect changes in the tendon, tendon sheath, and adjacent structures. The goal is to more reliably distinguish true biceps lesions from other causes of shoulder lameness and thus avoid misdiagnoses. (pubmed.ncbi.nlm.nih.gov, pubmed.ncbi.nlm.nih.gov)

From a therapeutic perspective, research mainly focuses on the question of which dogs benefit from conservative therapy and when arthroscopic procedures such as tenotomy make more sense. Large prospective studies are still lacking for many decisions. That is exactly why the outlook is primarily methodological: better imaging, standardized functional assessments, and robust long-term outcomes are intended to make treatment more individualized. (pubmed.ncbi.nlm.nih.gov, pubmed.ncbi.nlm.nih.gov)

Overall, research is clearly moving toward more precise shoulder diagnostics and more targeted, function-oriented therapy.

Frequently Asked Questions (FAQs)

1. What is an injury to the M. biceps brachii?
The biceps brachii muscle originates at the shoulder blade (supraglenoid tubercle) and inserts at the head of the radius. Its long tendon runs through a bony groove on the head of the humerus. Injuries range from tendinitis (tendon irritation) and tenosynovitis (inflammation of the tendon sheath) to partial or complete tendon rupture.
2. Which dogs are affected?
Most commonly affected are medium to large, athletically active, middle-aged dogs. Predisposed breeds include Labrador Retrievers, Golden Retrievers, Border Collies, Rottweilers, and German Shepherds. Dogs with a high activity level, such as agility dogs or service dogs, also have an increased risk.
3. What are the causes?
The most common cause is chronic overuse with microtrauma to the tendon, for example from repeated intense retrieving, jumping, or rough play. Acute injuries occur due to sudden falls or missteps. Degenerative changes with increasing age also play a role.
4. What symptoms does an affected dog show?
Typically, there is a gradually increasing forelimb lameness that worsens after exercise and improves with rest. The shoulder is often painful on extension and with pressure on the biceps tendon. The lameness becomes more pronounced when walking downhill or when jumping.
5. How is the diagnosis made?
The orthopedic examination with a targeted biceps test (flex the shoulder, extend the elbow) is indicative. X-ray rules out bony changes, and ultrasound visualizes the tendon and tendon sheath well. The most accurate method is MRI, supplemented by shoulder joint endoscopy (arthroscopy), which can be used both diagnostically and therapeutically.
6. How is a biceps tendon injury treated?
Mild tendinitis is treated conservatively with rest, non-steroidal anti-inflammatory agents, and physiotherapy. In chronic or more severe cases, intra-articular injections with corticosteroids or PRP, regenerative therapies such as shockwave therapy, and arthroscopic procedures such as tenotomy or tenodesis may be considered.
7. What are tenotomy and tenodesis?
In tenotomy, the biceps tendon is cut arthroscopically; it retracts downward and scars over. In tenodesis, the tendon is cut and reattached elsewhere, usually on the humerus. Both procedures relieve the damaged tendon and deliver very good results in many cases.
8. What role does physiotherapy play?
Physiotherapy is a key component at every stage. Passive range-of-motion exercises, massage, underwater treadmill, laser therapy, and targeted muscle building improve healing and help prevent recurrence / relapse. A gradual and controlled increase in load over several weeks is crucial.
9. How long does recovery take?
Mild cases treated conservatively often require 6 to 12 weeks of rest before the dog can bear full weight again. After arthroscopic procedures, rehabilitation time is usually 8 to 16 weeks. Loading too early often leads to recurrence / relapse.
10. What is the prognosis?
The prognosis is good with timely diagnosis and consistent treatment. With tenotomy or tenodesis, over 80 percent of dogs regain full weight-bearing ability. In chronic cases with pronounced secondary changes such as osteoarthritis, the prognosis is more guarded.

Literature

  • Gilley, R. S., Wallace, L. J., & Hayden, D. W. (2002). Clinical and pathologic analyses of bicipital tenosynovitis in dogs. American Journal of Veterinary Research, 63(3), 402–407. https://doi.org/10.2460/ajvr.2002.63.402
  • Kramer, M., Gerwing, M., Sheppard, C., & Schimke, E. (2001). Ultrasonography for the diagnosis of diseases of the tendon and tendon sheath of the biceps brachii muscle. Veterinary Surgery, 30(1), 64–71. https://doi.org/10.1053/jvet.2001.20336
  • Wall, C. R., & Taylor, R. (2002). Arthroscopic biceps brachii tenotomy as a treatment for canine bicipital tenosynovitis. Journal of the American Animal Hospital Association, 38(2), 169–175. https://doi.org/10.5326/0380169
  • Innes, J. F., & Brown, G. (2004). Rupture of the biceps brachii tendon sheath in two dogs. Journal of Small Animal Practice, 45(1), 25–28. https://doi.org/10.1111/j.1748-5827.2004.tb00191.x
  • Cook, J. L., Kenter, K., & Fox, D. B. (2005). Arthroscopic biceps tenodesis: Technique and results in six dogs. Journal of the American Animal Hospital Association, 41, 121–127. https://doi.org/10.5326/0410121
  • Bergenhuyzen, A. L. R., Vermote, K. A. G., van Bree, H., & Van Ryssen, B. (2010). Long-term follow-up after arthroscopic tenotomy for partial rupture of the biceps brachii tendon. Veterinary and Comparative Orthopaedics and Traumatology, 23(1), 51–55. https://doi.org/10.3415/VCOT-09-01-0005
  • von Pfeil, D. J. F., Steinberg, E. J., & Dycus, D. L. (2020). Arthroscopic tenotomy for treatment of biceps tendon luxation in two apprehension police dogs. Journal of the American Veterinary Medical Association, 257(11), 1157–1164. https://doi.org/10.2460/javma.2020.257.11.1157