How to Identify the Plantaris

The plantaris is a vestigial muscle that was used by primates for grasping with the feet. Its motor function is so minimal that it is frequently harvested for reconstructive surgery with little adverse effect and is absent in 9 percent of the population. The following steps will help you the plantaris muscle.

Difficulty: Moderate

Instructions

1. Read up on Latin roots to know that "plantaris" means "sole of the foot." This muscle moves the bottom of the foot.

2. Examine the plantaris to see that it acts like the gastrocnemius by weakly flexing the ankle and knee joints. The plantaris also has an extremely high density of proprioceptive sensors that may provide information about the position of the foot.

3. Observe how the plantaris originates above the lateral condyle of the femur just above the lateral head of the gastrocnemius.

4. Look at the insertion of the plantaris into the calcaneus medial to the calcaneal tendon or it blends with the calcaneal tendon. The tendon for the plantaris is sometimes referred to as the "freshman nerve" because it is so small it is frequently mistaken for a nerve by first-year medical students.

5. Research the nervous system to know that the nerve for the plantaris is the tibial nerve from the first and second sacral nerves.

6. Study the circulatory system to know that the blood supply for the plantaris is the sural branches of popliteal artery, muscular branches of peroneal artery and the posterior tibial artery.

Resources

• Read a medical glossary.