Human Movement Science & Functional Anatomy of the:

Gastrocnemius (and Plantaris)

by Brent Brookbush MS, PES, CES, CSCS, ACSM H/FS

What's in a name?

Gastrocnemius - Originating from the greek roots: "gastro" referring to stomach, and "kneme" referring to leg, or more specifically "shank" - as in lower leg.  This roughly translates into "stomach of the lower leg," likely referring to it's shape.

Plantaris - From the latin root plantar relating or pertaining to the sole of the foot.

Fibularis Muscles (Peroneals) - http://classconnection.s3.amazonaws.com/694/flashcards/597694/jpg/lateral_compartment_leg_muscles1312171716591.jpg

Gastrocnemius Muscles:

  • Origin:

      • Medial Gastrocnemius: Proximal and posterior part of the the medial condyle and adjacent part of the femur, capsule of the knee joint (11).
      • Lateral Gastrocnemius: Lateral condyle and posterior surface of the femur, capsule of the knee joint (11).

  • Insertion:  Just medial to the midline of the calcaneus via the achilles tendon (11).

    • This muscle is the most superficial of the posterior compartment muscles of the lower leg; enveloped by the crural fascia and lying on top of the soleus.  The proximal attachments of this muscle create the inferior borders of the popliteal fossa along with the plantaris on the lateral side.
    • Supported by a chair or using a wall for support, have your partner stand on their toes.  Course your fingers around the superficial elliptical heads of the gastrocnemius.  If you run your finger across these muscles you should note an indentation approximately midline dividing the lateral and medial heads. Coursing your fingers to the lateral borders of this muscle you will feel the broader, flatter muscle lying deep to the gastrocnemius - the soleus.  If you run your fingers inferiorly you will feel these softer, supple muscle blend into the denser, belt like achilles tendon which becomes almost tubular in shape as it extends into its insertion on the calcaneus.  Return to the gastrocnemius and