Plantaris Muscle Pain: Strains and Tears at the Back of the Leg

Strains or tears of the plantaris muscle at the back of the leg can cause pain and swelling similar to a calf strain or Achilles tendon tear. You may feel immediate pain, cramping, and other symptoms. Activities that involve lunging forward are often to blame for plantaris injuries.

The plantaris muscle and tendon are in a similar location to other muscles of the calf and the Achilles tendon. Thankfully, recovery from a plantaris muscle injury is typically much simpler.

This article explores the anatomy of the back of the leg and the symptoms, diagnosis, and treatment of plantaris muscle injuries.

Anatomy of the Back of the Leg

The gastrocnemius and the soleus muscles are he major muscles in the back of the leg. The gastrocnemius has two major portions, the medial and lateral heads of the gastrocnemius, and is closer to the skin. The soleus is located deeper in the leg. 

Together, the gastrocnemius and soleus muscles form the Achilles tendon, which blends into a tight tendon in the back of the heel.

The Achilles tendon attaches to the heel bone (the calcaneus). When the calf muscles contract, they point the foot downward. This motion is important in propelling the body forward when walking, running, and especially when sprinting. 

The plantaris muscle is a smaller component of the calf muscles. The plantaris muscle and tendon sit roughly in the center of the calf, between the two heads of the gastrocnemius.

Symptoms of Plantaris Strains and Tears

Plantaris muscle ruptures, which are the most common plantaris muscle injuries, occur most frequently during running or jumping. They have also been called "tennis leg" as many people who sustain this injury are athletes who are lunging forward, such as a tennis player might do.

Typical symptoms of a plantaris muscle rupture include:

• Sudden pain in the back of the calf
• A swelling or bunching of the calf muscle
• Swelling and bruising in the back of the leg
• Cramping and spasm sensations of the calf muscle

Diagnosing the Cause of Plantaris Muscle Pain

Confirming the reason behind your pain is essential, in large part to ensure the injury is not a more serious Achilles tendon tear.

Plantaris ruptures can also be confused with a blood clot in the large veins of the calf, called deep vein thrombosis (DVT), which can be dangerous.

If the diagnosis is unclear, there are tests that can be performed to confirm or exclude the diagnosis of a plantaris rupture. Those most often used are:

• Magnetic resonance imaging (MRI)
• Ultrasound

Both of these tests can be useful in confirming an injury to the plantaris muscle or to look for other possible causes of calf pain.

Treating Plantaris Injuries

Treatment of a plantaris muscle injury is almost always non-surgical. While the injuries can cause pain and disability, the symptoms almost always resolve with simple treatment steps.

R.I.C.E. (rest, ice, compression, elevation) is typically used first.

If the pain is significant, patients may require a brief time of immobilization or crutch use to allow the pain to subside.

Gradual increases in mobility and strength can be obtained with the assistance of an athletic trainer or physical therapist.

With conservative treatment, symptoms will gradually resolve over the course of several weeks. Full recovery may take up to eight weeks depending on the severity of the injury.

Summary

Running along with the other muscles of the calf, the plantaris muscle and tendon are in a similar location to the muscles of the calf and Achilles tendon.

Plantaris ruptures occur most often during running or jumping. Plantaris injuries can have similar symptoms to Achilles tendon tear, but recovery is much quicker.