First, we will review the anatomy of the soleus muscle. The soleus muscle originates at the posterior surface of the head and upper third of the fibular body, soleal line, and medial border of the tibia. It then inserts on the posterior surface of the calcaneus after joining the tendon of the gastrocnemius muscle. The soleus muscle is innervated by the tibial nerve. It is an important ankle plantar flexor that does not cross the knee joint. Now we will review the cross-sectional anatomy of the soleus muscle. The soleus muscle is highlighted here. The soleus muscle is just deep to the gastrocnemius muscle on the posterior aspect of the leg and posterior to the fibular vascular bundle and posterior tibial neurovascular bundle. Up to this point, we have presented the cross-sectional anatomy of the leg in the supine position. We will perform the soleus injection in the prone position. The leg is now oriented in the prone position so that the anterior aspect is located at the bottom of the screen. Here, the tip of the needle has been placed in the soleus muscle, traveling from medial to lateral through the medial head of the gastrocnemius muscle. The posterior tibial neurovascular bundle and fibular vascular bundle are located deep to the soleus muscle and will need to be avoided during this injection. Let's discuss the anatomy we expect to see on ultrasound. Outlined here is the soleus muscle. The circle on the right is highlighting the posterior tibial neurovascular bundle. The circle on the left is highlighting the fibular vascular bundle. Again, complete injection preliminary steps prior to beginning the procedure. Take time before the procedure to set up the room and make sure that you have adequate assistance. Collect equipment and position the patient. You will first need to orient yourself by scanning the target muscle region. The target muscle, the soleus, is circled in red here. Using Color Flow Doppler imaging, identify the vasculature to avoid during the injection. Here, the needle is being inserted from medial to lateral through the medial head of the gastrocnemius muscle. The needle remains superficial to the posterior tibial neurovascular bundle and fibular vascular bundle. Electrical stimulation can now be used to ensure proper needle tip positioning. Needle position is confirmed when isolated movement of the soleus muscle is seen on ultrasound. In some cases, you may also see plantar flexion of the ankle. Three key images are needed to confirm needle placement. These include the cross-sectional view of the target muscle, cross-sectional view of the vasculature adjacent to the target muscle, and length of the needle traversing to the target muscle. Once needle position is confirmed, botulinum toxin is injected into the target muscle. Finally, the needle is withdrawn.

soleus muscle

anatomy

injection technique

origin

insertion