Pain in the fibularis longus muscle can be disruptive, especially during walking. This muscle, located along the outer side of the lower leg and ankle, plays a significant role in foot mechanics. When it becomes irritated or injured, discomfort can arise, making simple movements challenging. Understanding its causes helps individuals address the issue and regain mobility.
Understanding the Fibularis Longus
The fibularis longus, also known as the peroneus longus, is a muscle in the lateral compartment of the lower leg. It originates from the upper fibula, the smaller lower leg bone. The muscle then extends downwards, with its tendon wrapping around the outer ankle bone (lateral malleolus) and continuing underneath the foot to attach to the medial cuneiform and first metatarsal bones on the inner side of the foot.
This muscle performs several functions for foot and ankle movement. Its primary actions include eversion, which involves tilting the sole of the foot away from the body’s midline, and assisting in plantarflexion, which is extending the foot downwards at the ankle. The fibularis longus also helps stabilize the ankle and maintain the arches of the foot during weight-bearing activities such as walking and running. This stability is crucial for balance, especially when standing on one leg.
Common Causes of Pain
Pain in the fibularis longus often stems from overuse or injury. A frequent cause is tendinopathy, inflammation or irritation of the fibularis longus tendon. This condition often develops due to repetitive stress, sudden increases in activity levels, or prolonged periods of standing or walking. Activities on uneven surfaces can also overstress these tendons, contributing to pain.
Muscle strain is another cause, when the muscle fibers are overstretched or torn. This can happen with forceful movements of the foot or ankle. Lateral ankle sprains, which are common injuries, can also damage the fibularis longus tendon, leading to persistent pain in the area even after the initial sprain subsides.
Improper footwear can contribute to fibularis longus pain by lacking adequate support, placing undue stress on the muscle and tendon. Certain foot structures, such as high arches (pes cavus), can also increase susceptibility to overuse because the heel may turn inward, requiring the fibularis tendons to work harder to stabilize the ankle. Direct trauma to the outer lower leg or ankle can also result in pain in this region.
Recognizing Symptoms and Diagnosis
Individuals typically experience pain along the outside of the ankle or lower leg, which often intensifies with activity such as walking, running, or prolonged standing. Tenderness to the touch along the course of the fibularis longus tendon, particularly behind the outer ankle bone, is also a common symptom. In some instances, there might be visible swelling or bruising in the affected area.
Weakness or instability when attempting to evert the foot (turn the sole outwards) can also indicate a fibularis longus issue. A clicking or popping sensation in the ankle might also be reported, especially if the tendon is unstable or subluxing. If the problem stems from a pinched nerve in the lower back, weakness in the muscle can occur.
Diagnosis Methods
Medical professionals typically diagnose fibularis longus pain through a physical examination and by reviewing the patient’s medical history. During the physical exam, the doctor may palpate the area to check for tenderness, assess the range of motion of the ankle, and perform strength tests like resisted eversion.
Imaging studies may be recommended. X-rays can rule out fractures, while ultrasound can visualize the tendons and detect inflammation or tears. Magnetic Resonance Imaging (MRI) offers more detailed soft tissue assessment, which is useful for identifying tears or tendinosis.
Relief and Recovery Strategies
Relieving fibularis longus pain and promoting recovery typically involves several conservative strategies aimed at reducing stress on the affected area. Rest and activity modification are often the first steps, which means temporarily reducing or stopping activities that aggravate the pain. For acute cases, applying the RICE method—Rest, Ice, Compression, and Elevation—can help manage pain and swelling. Over-the-counter pain relievers, such as non-steroidal anti-inflammatory drugs (NSAIDs), can also reduce discomfort and inflammation.
Once the initial pain subsides, stretching and strengthening exercises are often incorporated into a rehabilitation program. Gentle stretches for the calf and ankle, along with strengthening exercises for the fibularis muscles using resistance bands for eversion, can improve flexibility and muscle endurance. Proper footwear that offers adequate support is important, and custom or over-the-counter orthotics can help correct biomechanical issues that place excess stress on the muscle.
Physical therapy plays a significant role in recovery, with a therapist designing a personalized rehabilitation program that may include manual therapy, specific exercises, and gait analysis to identify and correct movement patterns. In cases of severe pain, a cast or walking boot might be used to immobilize the foot and allow the tendons to heal. It is important to seek professional medical evaluation if pain is severe, if there is an inability to bear weight, or if conservative measures do not lead to improvement within a few weeks.