Nerve supply to the accessory soleus muscle

Area of Science:

• Anatomy
• Human Anatomy
• Skeletal Muscle Anatomy

Background:

• Anatomical variations in the lower limb musculature are not uncommon.
• The soleus muscle, a key plantar flexor, can exhibit morphological anomalies.
• Understanding these variations is crucial for clinical diagnosis and surgical procedures.

Purpose of the Study:

• To describe a unique accessory soleus muscle found during cadaveric dissection.
• To detail the anatomical location, origin, insertion, and nerve supply of this anomalous muscle.
• To investigate the embryological origin of the accessory soleus muscle based on its nerve supply.

Main Methods:

• Gross anatomical dissection of a human cadaver.
• Detailed morphological examination of the accessory soleus muscle and its relationship to the soleus muscle.
• Nerve tracing and dissection of the tibial nerve branches supplying the soleus and accessory soleus muscles.

Main Results:

• An accessory soleus muscle was identified in the right leg, located medially between the tibia and tendo calcaneus.
• The anomalous muscle originated from the anterior aponeurosis of the soleus and inserted via a separate tendon onto the calcaneus.
• The accessory soleus muscle received nerve fibers from the anterior ramus of the tibial nerve, originating from the same fasciculus as the nerve supply to the soleus's bipenniform part.

Conclusions:

• The accessory soleus muscle represents a distinct anatomical variation.
• Its nerve supply pattern suggests an origin from the anteriorly innervated portion of the proper soleus muscle.
• This finding contributes to the understanding of lower limb muscle development and variations.