Soleus Tendon

tendo musculi solei

The soleus tendon merges with the gastrocnemius tendons to form the Achilles tendon but maintains a distinct medial contribution visible on cross-section. The soleus is the primary standing plantarflexor (active when the knee is extended in stance), while the gastrocnemius predominates in swing phase and running. Isolated soleus strains occur more proximally at the soleal line on the tibia in runners with high training loads.

Region: Lower Leg

Biomechanics

Function & Actions

Ankle plantarflexion during midstance when the knee is bent (the soleus is the primary plantarflexor during walking); weight acceptance phase stabilisation

Clinical Relevance

Clinical Notes

Soleus muscle tears occur at the soleal line origin on the posterior tibia, presenting as calf pain with a non-palpable gap (unlike gastrocnemius tears where a gap is palpable at the musculotendinous junction). MRI confirms the injury level. The soleus is the primary rehabilitation target in Achilles tendinopathy — heavy slow resistance calf raises with the knee bent (isolating the soleus) are the foundation of evidence-based Achilles rehabilitation.

Pathology

Common Injuries & Conditions

Soleus Muscle Tear

Proximal soleal muscle injury at the tibia origin producing deep calf pain without palpable gap managed with progressive loading.