Soleus muscle

The soleus muscle is a muscle of the pelvic limb located caudolaterally to the tibia and the stifle joint. It represents the deep, lateral part of the triceps surae muscle. Its development varies greatly depending on the species. It is absent in dogs and pigs.

Conformation: In domestic mammals, this is generally quite weak and thin. It is located at the craniolateral edge of the lateral head of the gastrocnemius muscle. In humans, it is much more important.

Origin: It originates on the proximal end of the fibula.

Insertion: On the lateral surface of the tendon of the gastrocnemius muscle. Then, via the common calcaneal tendon, to the calcaneal tuberosity.

Relations: In domestic mammals, this muscle is covered directly by the crural fascia, but may be partially covered by the lateral head of the gastrocnemius muscle, as in cats and rabbits. It lies between the gastrocnemius muscle and extensor digitorum lateralis muscle. It covers the border of flexor digitorum lateralis muscle.

Action: It is an accessory muscle of the gastrocnemius and therefore participates in the extension of the tarsal joint.

Vascularization: Subdivisions of the popliteal artery and caudal femoral arteries.

Nerve: Tibial nerve

Description: The Soleus muscle is located on the caudal part of the crus. In domestic mammals it is thin, poorly developed and weak, even absent in dogs and pigs. It is mainly an accessory muscle to the gastrocnemius, with which it forms the triceps surae muscle. It thus helps in its function of extending the tarsal joint. It inserts directly onto the gastrocnemius tendon, originating at the proximal end fibula. It is located superficially, directly covered by the crural fascia, between the gastrocnemius and the extensor digitorum lateralis muscle. It covers part of the flexor digitorum lateralis muscle. It is innervated and vascularized by the same vessels as the gastrocnemius, i.e. the tibial nerve, the subdivisions of the popliteal artery and caudal femoral arteries.

Variations:

• On equines, this muscle represents only a small, long fascicle that ends in a small tendon on the gastrocnemius tendon.