Plantaris

Looks like

A small muscle belly behind the knee with a very long, thin tendon running down beside the Achilles tendon.

What it does

Weakly helps the calf point the foot; of little functional importance.

Keeping it well

Missing in some people; its tendon is a spare for grafts. Most sudden calf 'tennis leg' tears are in the gastrocnemius, not here.

Related conditions

• Achilles tendon rupture
• Botulism
• Chronic venous insufficiency
• Compartment syndrome
• Fibromyalgia
• Frailty & falls in older age
• Growing pains
• Heat exhaustion & heatstroke
• Lymphangitis
• Lymphatic filariasis (elephantiasis)
• Lymphoedema
• Malnutrition & refeeding syndrome
• Muscular dystrophy
• Polymyalgia rheumatica
• Restless legs syndrome
• Rhabdomyolysis
• Sarcoma
• Sarcopenia
• Superficial thrombophlebitis
• Tetanus
• Varicose veins
• Venomous snakebite