GENERAL INFORMATION
The plantaris is a small, long muscle located in the posterior (back) part of the thigh. It is often considered part of the triceps surae muscle group, along with the gastrocnemius and soleus muscles. Despite its small size, the plantaris contribute to specific movements of the foot and ankle.
ORIGIN
This muscle originates from the lateral supracondylar ridge of the femur, also which is a bony ridge on the distal end of the thigh bone.
INSERTION POINT
The plantaris muscle inserts into the calcaneus (heel bone) via the Achilles tendon. It lies deep in the gastrocnemius muscle and contributes to the overall function of the triceps surae.
MAJOR ARTERIES
It receives its blood supply from the following arteries:
- Popliteal artery
- Posterior tibial artery
NEURAL INNERVATION
It is innervated by the tibial nerve, which arises from the sciatic nerve. The tibial nerve provides motor innervation to the plantaris, allowing it to contract as well as contribute to movement.
TRIGGER POINT
The plantaris muscle does not commonly develop specific trigger points that cause pain or discomfort.
CONCENTRIC FUNCTION
The concentric function of the plantaris muscle involves the shortening or contraction of the muscle. Although it is relatively weak compared to the gastrocnemius and soleus, it assists in plantar flexion of the foot, which involves pointing the foot downward.
ECCENTRIC FUNCTION
The eccentric function of the plantaris muscle refers to the controlled lengthening of the muscle while resisting an external force. It aids in movements such as lowering the heel from a raised position or decelerating the foot during landing.
ISOMETRIC FUNCTION
The isometric function of this muscle involves contracting the muscle without any change in length. Isometric contractions of the calf muscles, including it, occur during activities like standing or maintaining balance.
RELATED MUSCLE SCIENTIFIC NAMES
- Musculus plantaris
ANTAGONIST
The antagonist muscle to the plantaris is the tibialis anterior, which is also responsible for dorsiflexion of the foot (bringing the foot upward).
COMMON INJURIES
- Plantaris tendon rupture: In some cases, the plantaris tendon may rupture during forceful movements or activities, causing pain and limited mobility in the calf.
- Calf strain: While it is not typically the primary muscle involved in calf strains, it may be affected in combination with other calf muscles.
EXERCISES
- Calf raises: Performing calf raises targets the entire triceps surae muscle group, including the plantaris.
- Jumping rope: Engaging in jumping rope activities helps strengthen the calf muscles, including the plantaris.
- Running or jogging: These activities involve repetitive contraction of the calf muscles, including the plantaris.
STRETCHES
- Standing calf stretch: Placing the hands against a wall, one leg is extended behind while keeping the heel on the ground, stretching the calf muscles, including this muscle.
- Seated calf stretch: Sitting with legs extended, a strap or towel is wrapped around the foot, and gently pulling the toes towards the body to stretch the calf muscles, including the plantaris.
- Downward-facing dog pose: A yoga pose that stretches the entire posterior chain, including the calf muscles and the plantaris.