The soleus originates from which structures?

• A. Posterior surface of femur
• B. Soleal line; proximal, posterior surface of tibia and posterior aspect of head of fibula
• C. Lateral malleolus; distal fibula
• D. Anterior surface of tibia

Answer: (B)

The soleus starts from deep, broad attachments on the leg to support its role in powerful plantarflexion. It originates from the soleal line on the posterior tibia and from the proximal posterior surface of the tibia and the posterior aspect of the head of the fibula (often with contribution from the interosseous membrane). This combination explains its location and function, and it also fits with its insertion via the Achilles tendon onto the calcaneus. The areas listed in the other options belong to different muscles—posterior femur relates to muscles like the hamstrings or gastrocnemius’ femoral origins, the lateral malleolus of the distal fibula involves the peroneal muscles, and the anterior surface of the tibia is the origin for tibialis anterior.