Talocrural Region (Combined Ankle Joint)
Due to its intricacy this page will discuss (in combination) the three joints of the ankle and other ankle related movements/attachments.

Bones: The Tibia is in contact with the Fibula. The Tibia in contact with the Talus (refereed to as the main ankle bone) and sits just beneath the Tibia. The Talus is in contact with the Calcaneus which makes the bone of the heel.

Cartilage: Here there is a decent layer of cartilage mainly between the Tibia and the Talus and the Talus and the Calcaneus to help the joint move.

Ligaments: Because the fibula extends past the tibia it makes a great (supportive) surface for ligamentary attachments between all of the bones mentioned above. The Calcaneofibular ligament on the outside of the ankle is often injured when the ankle is rolled.

Tendons: Notable tendons include

• The Achilles tendon which is the thickest tendon in the body and runs from the Plantaris, Gastrocnemius, and Soleus muscles to the Calcaneus of the heel.
• The Peroneal tendon which runs from the calf down the back side of the end of the fibula and under it connecting to the fifth metatarsal of the foot.

Muscles: Major muscle include the Gastrocnemius and Soleus on the back of the leg which pull on the Achilles tendon pointing the foor down. Notably the Gastrocnemius has two heads connecting to each side of the end of the femur by the knee. The Tibialis Anterior is the only muscle that pulls the foot upwards, it starts on the outside of the Tibia on the lower leg and runs to inside of the ankle by the first metatarsal.

Mechanics: Because of the small size and shape of the ankle bones the angle of the joint is always decreasing therefore dorsiflexion is pulling the foot upwards and plantarflexion is pointing the foot downwards. Inversion is rolling the ankle inwards while Eversion is rolling the ankle outwards.

Range of motion: At the core of the joint the average plantarflexion is around 50 degrees downwards which is enough (in combination with foot muscles) put the foot/toes in line with the leg. As for dorsiflexion the ankle is able to flex roughly 30 degrees upwards. The ankle is able to roll inwards or outwards and lifting the side of the foot off the ground at roughly 5 degrees.

Manipulation:

• Sweeps usually involve hooking around the back of the opponent's ankle to take out the leg. What happens here (or what should happen more) is that rather than just pulling on the ankle, striking the Achilles tendon will simulate a contraction of the calf which pulls the heel. When done on an opponent will lift the heel just enough to transfer the weight it is supporting to the ball of the foot (out and away from the body) making it easier to pull the foot from under and opponent and thus felling them to the ground.
• In styles such as Jujutsu there are ankle locks where for example the top of the foot (of the opponent while lying on their back) is placed in the armpit of the locker. For this example the opponents left top of foot into the right armpit of the locker, the locker then takes their right arm then goes under the Achilles tendon and grabs their own left forearm, while the left hand is placed on the left shin of the opponent on the ground. The locker pulls down with their right shoulder, up with their right forearm, and down with their left hand. This intern over extends the top of the ankle causing a very decent amount of pain.

Support: The ankle is the lowest joint with the most importance to bearing the weight of the body, therefore during physical activities the weight of our body, the momentum as which we are moving, and gravity exert a force on our ankle that is larger than that of our body weight.
According to the North Austin Foot & Ankle Institute
Walking = 1.5x Body Weight
Running = 2x - 5x Body Weight
Jumping = 6x Body Weight
Skateboarding = up to 17x Body Weight
Many sports athletes and many martial arts (obviously depending on the intensity of training) are likely to fall between 6x to 17x.
And for this reason arts like Muay Thai or Taekwondo it is usually recommended to wear ankle wraps when training.

• If any of our members are avid skateboarders your opinion would be valued.

Usage: Besides walking and other body mechanics there is practically no usage of the joint (especially as a striking surface).

Injury: Many ankle injuries occur due to over inversion or over eversion (ankle rolling in or out).

• Sprain - is when the ligaments are stretched beyond their capacity and can cause tearing.
• Strain - is when the tendon or muscle is stretched beyond capacity. Often of concern is the Achilles tendon, which walking will be painful. And the Peroneal tendon which can be pulled out of place from around the end of the fibula.

Strengthening: Ankle rotations will help as well as walking briefly on the inside or outside of your feet to help strengthen the ankle. This only requires a minute or so a day and will improve ankle support during high impact activities.

For information on additional joints please refer back to the Joints page.

References:

1. North Austin Foot & Ankle Institute, http://www.northaustinfeet.com/sports-injuries/ added 7/1/15