Calf Strain Anatomy
To better understand calf strain, it helps to understand the anatomy of the leg.
The entire leg contains four bones:
- Femur: thighbone
- Patella: kneecap
- Tibia: thick bone in the front of the lower leg
- Fibula: thin bone on the side of the lower leg
Below the knee, the lower leg contains two long bones, called the tibia and fibula. The muscles of the lower leg control movement of the foot and ankle. The back of the lower leg is called the calf.
The gastrocnemius is the largest muscle in the calf. The gastrocnemius muscle is attached to the femur in the back of the knee, and turns into the Achilles tendon. The Achilles tendon attaches to the heel. The gastrocnemius flexes the leg at the knee, and plantar flexes the foot (points the toes).
Leg anatomy examples:
- Anderson SJ. Lower extremity injuries in youth sports. Pediatr Clin North Am. 2002 Jun;49(3):627-41. 
- Beiner JM, Jokl P. Muscle contusion injury and myositis ossificans traumatica. Clin Orthop Relat Res. 2002 Oct;(403 Suppl):S110-9. 
- Kirkendall DT, Garrett WE Jr. Clinical perspectives regarding eccentric muscle injury. Clin Orthop Relat Res. 2002 Oct;(403 Suppl):S81-9. 
- Russell GV Jr, Pearsall AW 4th, Caylor MT, Nimityongskul P. Acute compartment syndrome after rupture of the medial head of the gastrocnemius muscle. South Med J. 2000 Feb;93(2):247-9.