Plantaris muscle

The plantaris muscle is one of the posterior calf muscles and is a long, thin, variably developed muscle which runs from the femur to the Achilles tendon.

Origin and insertion

The plantaris muscle arises from the posterosuperior aspect of the lateral femoral condyle close to the origin of lateral head of gastrocnemius. There is often an attachment to the oblique popliteal ligament. Posterior to the knee, plantaris runs obliquely from the lateral to medial side.

In the calf, it lies in between the medial head of the gastrocnemius and soleus (long arrow). Distally, the tendon finally inserts into the medial aspect of the tendoachillis.

Plantaris can have variable size, but in most cases is difficult to demonstrate on routine MRI studies. 

Function

Plantaris acts weakly to plantar flex the foot and flex the knee. It is considered a vestigial muscle, and can be used by the orthopaedic surgeons as graft in reconstructions.

In up to 10% of legs plantaris is absent, and in a smaller number it may be duplicated 3.

It is well seen when there is fluid collection in the myofascial junction between gastrocnemius and soleus, commonly secondary to strain of the medial head of gastrocnemius (tennis leg).


Lower limb anatomy
Share Article

Article Information

rID: 6012
Section: Anatomy
Synonyms or Alternate Spellings:
  • Plantaris Muscle

Support Radiopaedia and see fewer ads

  • Drag
    Figure 1: plantaris muscle
    Drag here to reorder.
  • Drag
    Figure 2: superficial leg muscles
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.