Plantaris: Pain Pattern and Treatment
The plantaris is a small muscle at the back of the knee with the longest tendon in the body, running down the calf to the heel beside the Achilles. It is a weak helper of the calf muscles. Its documented pattern is pain at the back of the knee that runs down into the upper calf. It is found alongside gastrocnemius trigger points and cleared with them.
Attachments and action
Origin: The lateral supracondylar line of the femur, above the outer head of the gastrocnemius.
Insertion: The back of the calcaneus, beside or with the Achilles tendon.
Action: Weak plantar flexion of the ankle and flexion of the knee; a helper of the gastrocnemius.
Where the pain is felt: The back of the knee. Down into the upper calf, to the middle of the calf at most.
Common causes: A sudden push-off, as in a sprint start or a jump; running on hills; a long period standing on the toes; a knee held bent for hours; a calf strain that left the back of the knee sore.
Patients say: "It is right behind my knee and runs into my calf." "It started when I pushed off to run." A calf that feels tight at the top.
When to get evaluated: A sudden snap or pop in the calf with swelling and bruising needs a calf tear assessed. Back-of-knee pain with swelling, warmth, or redness of the calf needs a blood clot ruled out first. A lump behind the knee needs assessment.
How this muscle is examined and treated
Examination tests plantar flexion with the knee bent and straight, presses the back of the knee just above the outer calf head for the point that reproduces the pain, and checks the gastrocnemius alongside it. Needling here addresses the muscle at the back of the knee, with the vessels there located first. Assessment and treatment happen in the same visit.
Related conditions
Knee PainAnkle & Foot PainSports & Performance Injuries
This page is educational. It describes muscle referral patterns commonly associated with pain; it does not diagnose your condition. Individual patterns vary. For evaluation of your specific pain, see a licensed clinician. Seek immediate medical care for emergencies. Eugene Baek, L.Ac. · New Jersey License 25MZ00080600