This paper reports an anatomic study of the soleus muscle and clinical applications of the findings derived from the study. Soleus neurovascular anatomy was studied in 86 limbs by dissection and specimen angiography. A consistently present bipenniform muscle morphology was found with medial and lateral subunits that had independent distal neurovascular supplies. This anatomic feature allows surgically splitting the muscle for transfer of one-half the muscle as a flap (hemisoleus muscle flaps). A series of 33 patients using both medial and lateral hemisoleus flaps in both proximally and distally based transfer is analyzed and illustrative examples are presented. The primary value of this technique is the ability to retain one-half the innervated soleus muscle in situ to preserve foot plantar flexion power in ambulatory patients. In addition, hemisoleus flaps have an extended arc of rotation as compared with that of conventional soleus muscle flaps.