Soleus
The soleus is a flat muscle deep to the gastrocnemius in the calf. Unlike the gastrocnemius, it does not cross the knee joint and is specialized for postural standing and endurance activities.
Origin, Insertion, Action, Innervation
OOrigin
Soleal line and medial border of tibia, posterior head and upper shaft of fibula.
IInsertion
Calcaneus via the calcaneal (Achilles) tendon (shared with gastrocnemius)
AAction
- • Plantarflexion of the ankle
- • Postural muscle for standing (prevents forward sway)
NInnervation
Tibial nerve (S1, S2)
Blood Supply
Posterior tibial artery, fibular (peroneal) artery
Clinical Relevance
The soleus is primarily a postural muscle and is important for maintaining balance during standing. Soleus muscle pump helps return venous blood to the heart. Soleus can be a site of deep vein thrombosis (DVT) and strain injuries.
Palpation
Difficult to palpate directly due to overlying gastrocnemius. Can be felt at the sides of the gastrocnemius when the foot is plantarflexed.
Study Tips
- ✓Does NOT cross the knee (unlike gastrocnemius)
- ✓Postural muscle - active during standing
- ✓Joins gastrocnemius to form Achilles tendon
Study Soleus with AI
Point your camera at any muscle and get instant identification with complete details.
Download AnatomyIQSoleus FAQs
Common questions about the soleus
The gastrocnemius has two heads from the femur and crosses the knee joint. The soleus originates from the tibia and fibula and does not cross the knee. Both plantarflex the ankle and join to form the Achilles tendon.
The soleus contains predominantly slow-twitch (Type I) muscle fibers, making it well-suited for sustained contraction during standing. It constantly activates to prevent forward sway and maintain balance.
The soleus muscle pump refers to the role of soleus contraction in compressing deep veins of the leg, helping to return venous blood to the heart. This is important for preventing venous stasis and DVT.
The soleus is innervated by the tibial nerve, carrying fibers from the S1 and S2 nerve roots. This is the same nerve that innervates the gastrocnemius.