Flexor digitorum longus

Looks like

A deep calf muscle on the inner back of the shin; its tendon passes behind the inner ankle and splits for the four small toes.

What it does

Curls the small toes down and helps push off and support the arch.

Keeping it well

Surgeons use its tendon to replace a failed tibialis posterior in flat foot; its tendon passes through the tarsal tunnel.

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