GENERAL INFORMATION
The soleus is a powerful muscle in the lower leg’s posterior (back) part. It is one of the two primary muscles comprising the triceps surae, commonly known as the calf muscle. It plays a vital role in various movements, such as walking, running and maintaining posture.
ORIGIN
The soleus muscle originates from the posterior surface of the head, the upper third of the fibula (a bone in the lower leg) and the medial border of the tibia (the more significant bone in the lower leg).
INSERTION POINT
The soleus muscle merges with the gastrocnemius muscle to form the Achilles tendon, which inserts into the calcaneus (heel bone). The Achilles tendon is the largest and strongest tendon in the human body.
MAJOR ARTERIES
The thigh soleus muscle receives its blood supply primarily from the following arteries:
- Posterior tibial artery
- Peroneal artery
NEURAL INNERVATION
The tibial nerve innervates the soleus muscle, which arises from the sciatic nerve. The tibial nerve provides motor innervation to the soleus, allowing it to contract and produce movement.
TRIGGER POINT
A common trigger point in the soleus muscle is located in the belly of the muscle. Trigger points in this area can cause pain and tightness, often radiating into the foot or up the back of the leg.
CONCENTRIC FUNCTION
The soleus muscle’s concentric function involves the muscle’s shortening or contraction. It is primarily responsible for the foot’s plantar flexion, which points it downward.
ECCENTRIC FUNCTION
The eccentric function of the soleus refers to the controlled lengthening of the muscle while resisting an external force. It involves movements such as lowering the heel from a raised position or decelerating the foot during landing.
ISOMETRIC FUNCTION
The isometric function of the soleus muscle involves contracting the muscle without any change in length. Isometric contractions of the calf muscles occur during activities like standing or maintaining balance.
RELATED MUSCLE SCIENTIFIC NAMES
- Soleus muscle (Musculus soleus)
ANTAGONIST
The antagonist muscle to the soleus is the tibialis anterior, which is responsible for dorsiflexion of the foot (bringing the foot upward).
COMMON INJURIES
- Soleus strain: Overstretching or tearing of the soleus muscle due to sudden movements or excessive physical activity.
- Achilles tendonitis: Inflammation of the Achilles tendon, often caused by repetitive stress or overuse.
- Calf cramps: Painful involuntary contractions of the calf muscles, typically caused by dehydration or muscle fatigue.
EXERCISES
- Calf raises: Standing on the edge of a step or platform and raising the heels to work the muscle.
- Seated calf raises: Sitting on a chair or bench with knees bent and feet flat on the floor, then lifting the heels to target the muscle.
- Leg press: A leg press machine performs calf presses, targeting gastrocnemius and soleus muscles.
STRETCHES
- Standing calf stretch: Placing the hands against a wall, one leg is extended behind while keeping the heel on the ground, stretching the muscle.
- Seated calf stretch: Sitting with legs extended, a strap or towel wrapped around the foot, and gently pulling the toes towards the body to stretch the muscle.
- Downward-facing dog pose: A yoga pose that stretches the entire posterior chain, including the soleus muscle.