The lower leg is comprised of two major bones; the tibia and the fibula. The connect to the upper thigh bone, femur, and the ankle by ligaments. The tibia is commonly known as the shin bone and is the weight bearing bone in the lower leg. The fibula is located on the outside of the leg and doesn’t actually have any weight placed on it while walking.
The tibia and fibula are connected to the femur, thigh bone, by the knee ligaments.
- 1. MCL (Medical Collateral Ligament)
- 2. LCL (Lateral Collateral Ligament)
- 3. PCL (Posterior Collateral Ligament)
- 4. ACL (Anterior Collateral Ligmanet)
The tibia and fibula are connected to the ankle by the ankle ligaments.
Ligaments on the outside of the angle.
The major ligaments in the ankle that are most commonly sprained are located on the outside of the ankle. These are sprained with “inversion sprains)
- Anterior Talofibular Ligament
- Calcaneofibular Ligament
- Posterior Talofibular Ligament
- Deltoid Ligament
Ligaments on the inside of the ankle. This is sprained with “eversion sprains”.
The muscles of the lower leg are classified by departments: the posterior, anterior and lateral compartments.
Posterior Compartment (3 muscles)
These muscles form the achilles tendon. The more flexible and strong these muscles are, the less prone you are to achilles tendon injuries, ankle sprains and plantarfascitis.
This is what we all call our “calf muscle”. It is the largest and strongest of the lower leg muscles. This muscle is most active when the leg is straight helping to point the ankle and bend the knee.
Plantaris (below the Gastrocnemius)
This muscle is absent in about 10-15% of the population.
Helps point the foot when the knee is bent.
This is helps support the arch of the foot. Commonly involved in shin splints.
Flexor Digitorum Longus
Curls the toes of the foot and helps point the foot
Flexor Hallucis Longus
This is the muscle of the big toe; it helps to curl it. It also helps point the ankle and turn the ankle inward.
Lateral Compartment (2 muscles)
These muscles help pull the ankle outward. These are important in stabilizing the ankle and play a key role in the rehabilitation of an ankle sprain. If a person sprains their ankle and stretches out the ligaments; these muscles will aid in better stabilizing the ankle.
- Peroneus Longus
- Peroneus Brevis
Anterior Compartment (4 muscles)
This helps to pick up the foot. This often becomes weak in older people as they become less active. As the muscles gets weak, it is harder to pick up the foot so that the toes can clear the ground when walking leading to a higher risk of falls.
Extensor Digitorum Longus
This muscles helps to lift up or extend the toes
Extensor Digitorum Hallucis
This muscle lifts or extends the big toe.