Zone 2 of the gastrosoleus complex corresponds to which structure?

• A. Myotendinous junction
• B. Gastroc muscle belly
• C. Achilles tendon
• D. Plantaris tendon

Answer: (A)

The main idea here is where force is transmitted from the contracting muscle into the tendon. Zone 2 of the gastrosoleus complex sits at the musculotendinous junction—the point where the gastrocnemius and soleus muscle fibers blend into the Achilles tendon. This junction is a transition zone between contractile muscle tissue and the noncontractile tendon, making it a common site for strain as the tissue changes its mechanical properties and handles shear forces during plantarflexion. Clinically, injuries at this junction present with focal calf pain and weakness on resisted plantarflexion, reflecting disruption at the muscle–tendon transition rather than within the muscle belly or in the tendon proper. The muscle belly is proximal to this zone, and the Achilles tendon proper lies distal to it, with the plantaris tendon a separate structure.