Exploring the Plantaris Muscle: Anatomy and Common Injuries

Individuals who engage in sports and physical activities that involve lunging forward while running or jumping can sustain a plantaris muscle injury. Can understanding the anatomy of the back of the leg and the symptoms help diagnose and treat plantar muscle injuries?

Plantaris Muscle

The plantaris muscle is a long, narrow muscle in the calf that runs along the back of the leg. It’s part of the Triceps Surae, a group of muscles in the calf that, along with the gastrocnemius and soleus muscles, makes up the bulk of the back of the leg. It is located in the superficial posterior compartment 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. Individuals may feel immediate pain, cramping, and other symptoms.

Anatomy

The gastrocnemius and soleus muscles are the major muscles, with the soleus located deeper in the leg. Together, they form the Achilles tendon, which blends into a tendon in the back of the heel and attaches to the heel bone/calcaneus. When the calf muscles contract, they point the foot downward, propelling the body forward when walking, running, and sprinting. The plantaris muscle and tendon sit more or less in the center of the calf, between the two heads of the gastrocnemius. Around 7% to 20% of the population are born without plantaris muscles. There are variations, such as having a double- or triple-headed plantaris muscle. (Olewnik Ł. et al., 2020) However, individuals that do not have the muscle or have a variation have not been shown to affect long-term or short-term mobility.

Symptoms

Plantaris muscle ruptures are the most common injury and occur often during running or jumping. (Spang C. et al., 2016) Many who sustain this injury are athletes who have to lunge forward. Common symptoms include:

• Sudden onset pain behind the calf.
• Swelling of the calf muscle.
• Muscle knots or myofascial trigger points of the calf muscle.
• Swelling and bruising in the back of the calf area.
• Cramping in the calf muscle.
• Spasm sensations of the calf muscle.
• Symptoms of a plantaris muscle strain are less severe, with the common signs being tightness and pain during and after physical activity.

Diagnosis

Plantaris muscle tears differ from Achilles tendon tears because the foot can be pointed downward following the rupture, whereas an Achilles tear cannot. Plantaris ruptures can also be confused with a blood clot in the large veins of the calf, called deep vein thrombosis/DVT. (Rohilla S. et al., 2013) Tests like MRI or ultrasound can be performed to confirm or exclude a plantaris rupture. Both can be useful for verifying whether the injury is a strain or tear and identifying other possible causes of calf pain.

Treatment

Treatment is typically non-surgical. While the injuries can cause pain and disability, the symptoms almost always resolve with conservative treatments and therapies. Rest, ice, compression, and elevation are the first line used and may be all that is needed for a muscle strain. Short-term use of NSAIDs may be recommended for a strain or tear to reduce pain and inflammation. (Morelli K. M. et al., 2018) If the pain is profound or there is a tear, patients may require short-term immobilization or the use of a crutch for the pain to subside. With the assistance of a physical therapist, sports chiropractor, and athletic trainer, gradual increases in mobility and strength can be obtained. Symptoms usually gradually resolve over several weeks. Full recovery may take up to eight weeks, depending on the severity of the injury.

Injury Medical Chiropractic and Functional Medicine Clinic works with primary healthcare providers and specialists to develop customized treatment programs through an integrated approach to treating injuries and chronic pain syndromes, improving flexibility, mobility, and agility, relieving pain, and helping individuals return to normal activities. If other treatments are needed, Dr. Jimenez has teamed up with top surgeons, clinical specialists, medical researchers, and rehabilitation providers to provide the most effective treatments.

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References

Olewnik, Ł., Zielinska, N., Karauda, P., Tubbs, R. S., & Polguj, M. (2020). A three-headed plantaris muscle: evidence that the plantaris is not a vestigial muscle?. Surgical and radiologic anatomy : SRA, 42(10), 1189–1193. doi.org/10.1007/s00276-020-02478-8

Spang, C., Alfredson, H., Docking, S. I., Masci, L., & Andersson, G. (2016). The plantaris tendon: a narrative review focusing on anatomical features and clinical importance. The bone & joint journal, 98-B(10), 1312–1319. doi.org/10.1302/0301-620X.98B10.37939

Rohilla, S., Jain, N., & Yadav, R. (2013). Plantaris rupture: why is it important?. BMJ case reports, 2013, bcr2012007840. doi.org/10.1136/bcr-2012-007840

Morelli, K. M., Brown, L. B., & Warren, G. L. (2018). Effect of NSAIDs on Recovery From Acute Skeletal Muscle Injury: A Systematic Review and Meta-analysis. The American journal of sports medicine, 46(1), 224–233. doi.org/10.1177/0363546517697957