Soleus

Introduction

Soleus is a powerfull lower limb muscle which along with gastronemius and plantaris forms the CALF muscle or TRICEPS SURAE.It runs from back of knee to the ankle. Its name is derived from the Latin word, "solea," meaning "sandal."It is located in superficial posterior compartment of the leg.

The soleus muscle contained predominantly slow twitch (Type I) fibers with the mean for all subjects being 80% (range 64 to 100%). In contrast the gastrocnemius muscles only contained 57% slow twitch fibers (range 34–82%).

Anatomy

ORIGIN

• posterior surface of the head and upper 1/3 of the shaft of the fibula;
• middle 1/3 of the medial border of the tibia, tendinous arch between tibia and fibula.
  

INSERTION

Into calcaneus with gastrocnemius by way of achilles tendon

ACTION

• Plantar flexion of the foot at the ankle;
• Reversed origin insertion action: when standing, the calcanius becomes the fixed origin of the muscle;
• Soleus muslce stabilizes the tibia on the calcaneus limiting forward sway.
  

NERVE SUPPLY

Tibial nerve, L4, L5, S1 , S2

SYNERGISTS

Gastrocnemius, Plantaris, Tibialis posterior, Peroneus longus and Brevis, FHL and FDL.

ANTAGONIST

Tibialis anterior

BLOOD SUPPLY

• Blood supply of the soleus muscle is from peroneal artery proximally and the posterior tibial artery distally;
• Muscle has a mixed blood supply;
• Vascular supply of the soleus is from popliteal, posterior tibial, & peroneal vascular pedicles to the proximal muscle, peroneal pedicles to distal lateral belly, and segmental posterior tibial pedicles to distal medial belly;
• w/ distal pedicles from the posterior tibial artery ligated & based on proximal pedicles from the posterior tibial and peroneal arteries, muscle can be transposed medially or laterally to cover defects in middle third of the leg;
• Proximal vasculature arises directly from the popliteal vessels and can reliably carry all but the distal 4 to 5 cm of the muscle;
• Intramuscularly, vasculature of the soleus divides into a bipenniform segmental pattern;
• w/ this vascular pattern, either half of the soleus muscle can be used, leaving a functional hemisoleus muscle intact