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The Ankle

Understanding the Ankle

The ankle is a complex joint it is not made up of only 1 joint like many other joints in the body. In fact, there are 4 joints that work together to support our lower body. The ankle is connected to our lower body with 2 main bones, the tibia and the fibula as pictured on the right.

 

FOUR JOINTS OF THE ANKLE


1. Tibiofibular joint is a syndesmotic joint, which means there is extremely limited movement. This joint connects the tibia and fibula. The main stabilizers of this joint are the anterior and posterior tibiofibular ligaments. Since this joint is not moveable, it takes a high amount of force for it to be injured and is very uncommon.

2. Talocrural joint is made up of the tibiotalar and tibiofibular complexes. It is a synovial hinge joint, which means it’s responsible for bringing the foot up and pushing it down. The talocrural joint forms the ankle hinge point. This joint is the most common location referred to as the “ankle joint”.

 

3. Subtalar joint. It is a plane synovial joint which is similar to many other joints the body. It is supported by multiple ligaments that binds the talus and calcaneus (heel) together. This joint is very important in allowing your foot to adjust to uneven terrain while moving by shifting from side to side. It is also very important in athletic movements such as pivoting or turning with a fixed foot. This movement is essential for proper gait, but can lead to increased risk of injury if due to hypermobility and over rotation.

4. Tarsal joint. This joint is located near the midfoot. It combines bone articulations and ligaments. It is the furthest joint within the “ankle”. This is also a synovial joint and assists the subtalar joint in raising or lowering the foot.

Muscles

The ankle consists of multiple muscles, due to the size and complexity of the ankle joints. It is often easy to strain these muscles. There are many groups of small and muscles, we aim to list the muscles that perform bulk of the movements below.

The peroneal muscles run on the outside edge of the ankle and foot. These muscles allow the ankle to bend downward and outward.

The calf muscles (gastrocnemius and soleus), connect to the Achilles tendon. These muscles work in tightening and relaxing of the calf. They allow the ankle to bend downward and upward.

The posterior tibialis muscle, which supports the arch of the foot and enables the foot to turn inward.

The anterior tibialis muscle, which enables the ankle and foot to turn upward. The complexity of the ankle’s muscular and ligament structure creates many possible opportunities for injuries when the ankle is pushed beyond its normal range of motion.

Tendons

Tendons are elastic tissues that connect muscles to bones. The tendons main role is to stabilize the ankle. There are two major tendons in the ankle.

  1. Peroneal tendons in the foot run side by side behind the outer ankle bone. One peroneal tendon attaches to the outer part of the midfoot, while the other tendon runs under the foot and attaches near the inside of the arch. The main function of the peroneal tendons is to stabilize the foot and ankle and protect them from sprains. Notice the colour of the tendons, they are white. Whereas muscles are red, this is due to blood flow.
  2. Achilles Tendon is united by the gastrocnemius and soleus muscles (calf muscles) The achilles tendon then inserts into the calcaneus. The uncommon referral for the achilies tendon is also called the calcaneus tendon. This tendon is the largest and strongest tendon in the body. When the calf muscles flex, the achilles tendon pulls on the heel. This movement allows us to stand on our toes when walking, running, or jumping. This is the one tendon in our body that is extremely prone to injury.

Ligaments

Ligaments are designed to connect one bone to another. They are soft tissue structures that are strong, but not particularly flexible. Once stretched, they tend to stay stretched, if they stretch too far, they can snap. Ligaments join the ankle bones and provide stability.

The ankle has 7 main ligaments, 3 of which make up the lateral ligament complex.

The medial ligament complex consists of 3 ligaments also known as the deltoid ligament complex. These group of ligaments support the entire inner side of the ankle joint.

  • Anterior talofibular ligament connects the front of the talus bone to the shin bone. (fibula)
  • Calcaneofibular ligament connects the heel bone to the shin bone.
  • Posterior talofibular ligament connects the rear of the talus bone to the tibula.

In addition, there are also the ligaments listed below.

  • Anterior inferior tibiofibular ligament connects the tibia to the fibula
  • Posterior inferior tibiofibular ligament and the transverse ligament, these crisscross the back of the tibia and fibula
  • Interosseous ligament rests between the tibia and fibula and runs the entire length of the tibia and fibula, from the ankle to the knee.

Cartilage

This is the cushioning that is provided to your ankle joint, ultimately, they act as a shock absorber, cartilage wears out and cannot repair itself.  The ankle’s cartilage differs from other joints in two ways.

  1. The cartilage found in your ankle is a lot tougher than other joints such as the knee. This is due to the density of fibrocartilage material.
  2. However, the cartilage in your ankle is also very thin compared to other joints. Cartilage thickness ranges from about 1 to 1.7 mm thick, whereas cartilage in a knee joint can range1 to 6 mm thick.

3 of the 4 joints we have listed previously contain cartilage. The joint which does not contain cartilage is the tibiofibular joint. The image above identifies areas of cartilage in light blue colour.

Joint Capsule (lubrication membrane)

The capsule is a thick, fibrous structure that wraps around the ankle joint. Inside the capsule is the synovial membrane which is lined by the synovium, a soft tissue that secretes synovial fluid when it gets inflamed and provides lubrication for the ankle.

Joint Sacs

There are many bursa sacks of various sizes in and around the ankle joints. These sacs are filled with fluid to cushion the joint and reduce friction between muscles, bones, tendons and ligaments. Repetitive movements or prolonged pressure can irritate the bursal sacs.

The 3 main bursal sacks for the ankle joint is;

  1. Subcutaneous bursa
  2. Calcaneal bursa
  3. Retro-calcaneal bursa

Pathological Conditions of the Ankle

Ankle Osteoarthritis:

Osteoarthritis is the most common form of arthritis, and often affects the ankles. In fact, since the cartilage is different in an ankle joint compared to other joints some studies have shown osteoarthritis to be 9 times less likely to develop in the ankles compared to the knee joints. This is odd given the cartilage structure in the ankles are so thin and bear more weight compared to the knees and hips. Caused by aging and wear and tear of cartilage, osteoarthritis symptoms may include pain, stiffness, and swelling. Osteoarthritis is not simple to understand, there are many links with the wear and tear of cartilage that also affects every other part of your joint. We discuss this in our treatment information pack.

Septic Arthritis:

An infection caused by bacteria, a virus, or fungus inside the ankle can cause inflammation, pain, swelling, and difficulty moving the ankle. Although uncommon, septic arthritis is a serious condition that usually gets worse quickly without treatment.
GOUT: A form of arthritis caused by buildup of uric acid crystals in a joint. The ankle joint may be affected, causing episodes of severe pain and swelling.

Pseudogout:

A form of arthritis similar to gout, caused by calcium pyrophosphate crystals depositing in the ankle or other joints.
Issues that often occur with Osteoarthritis

Tendonitis:

Inflammation of the tendons that are connecting muscle to bone. Tendonitis can be very common. It can occur due to simple overuse, overstrain or even underuse. Tendons can become weak very quickly and they take a very long time to repair due to lack of blood flow.

Cartilage Tear:

This is rare in the ankle joint since the cartilage is extremely dense. However, it is still possible. The most common type of cartilage tear occurs with twisting motions of the ankle. Large tears may cause the ankle to physically lock. Tears can occur due to injury or long-term degeneration of the cartilage due to osteoarthritis.

Ligament Tears or Sprains:

“Rolling the ankle” very common injury. This can cause the calcaneal and/or talofibular ligaments to stretch beyond their normal capacity. These strains can be extreme, therefore leading to a tear. They can be associated with pain, swelling, and regular instability.

Peroneal Subluxation:

The peroneal tendons can slide abnormally or dislocate along the side of the foot. Surgery may be necessary to relocate the tendons in the proper location if subluxation is severe.

Bursitis:

Pain, swelling, and warmth in any of the bursae of the ankle. Bursitis often occurs from overuse or injury.

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