Accessory Soleus
Last updated:
08/09/2025Della Barnes, an MS Anatomy graduate, blends medical research with accessible writing, simplifying complex anatomy for a better understanding and appreciation of human anatomy.
What is the Accessory Soleus
The accessory soleus is the most common accessory muscle found in the calf and ankle of the human body. It is relatively rare, occurring in only about 0.7% to 5.5% of people. Among those who have it, only around 15% have it in both feet, and men are about twice as likely as women to develop this muscle.
When present, the accessory soleus typically appears as a swelling at the back of the ankle. In some individuals, it causes no symptoms, while in others it may become painful, especially after intense physical activity or exercise.
Anatomy
Location and Attachments
Origin
The accessory soleus typically arises from the lower front portion of the soleus muscle, though in some cases it originates directly from the surface of the tibia or fibula. It is enclosed by a fascial covering that separates it from the much larger soleus muscle.
Filename: Accessory Soleus (Caption: Accessory Soleus Muscle)
Insertion
The muscle belly descends toward the back of the heel, but its insertion point can vary considerably. It may merge with the Achilles tendon or insert directly onto the superior or middle region of the posterior surface of the calcaneus (heel bone).
Innervation
The accessory soleus is supplied by the tibial nerve, which is a branch of the sciatic nerve.
Blood Supply
Its vascular supply comes from the posterior tibial artery.
References
- Accessory Soleus Muscle: Radiopaedia.org
- Accessory Muscles of the Ankle: Radsource.us

Della Barnes, an MS Anatomy graduate, blends medical research with accessible writing, simplifying complex anatomy for a better understanding and appreciation of human anatomy.
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