Bones of the Ankle

BiologyHuman biology

Ankle Joint

The ankle joint is a complex system of a combination of bones, ligaments and muscles that hold together the foot in place. Built to serve several purposes like bearing weight, mobility, adaptability and stability, the ankle and the foot together serve as a connection to the ground. The ankle must withstand body weight as well as to adapt to the changing surfaces on which we walk.

The ankle is made up of two joints − the true ankle joint and the subtalar joint.

  • The true ankle joint is a specially designed joint that holds together the leg bones (tibia and fibula) and the foot (talus). These three bones, tibia, fibula, and talus, form the true ankle joint. Tibia and fibula are the bones in the lower leg that joins the knee and the ankle.

  • The subtalar joint, which lies just beneath the true ankle joint, consists of the talus on top and the calcaneus (heel bone) at the bottom. The subtalar joint is responsible for the foot’s sideways movement, namely inversion and eversion.

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Tibia

This inner, thicker bone of the two bones in the lower leg is called the shin bone. The tibia is the stronger bone that runs to the ankle joint.

Fibula

Almost the same length as Tibia, the Fibula is much thinner than that. Both of these bones are held together strongly by tibiofibular ligaments.

These two bones combine to form a bracket shaped socket and hold the talus bone snugly. This socket is called the mortise.

Talus

Resting on the heel bone, the Talus forms the lower portion of the foot. Talus is connected to the ankle joint and is also known as the ankle bone.

Fitting into the mortise, wedge-shaped Talus is broad on the anterior with a narrow posterior end

Tibia, fibula, and talus combine in the ankle joint. Each of these bones is firmly held in place by ligaments. The ankle joint is a hinge joint allowing the motion of the foot from 20 degrees to 50 degrees from the resting position.

Movements of the Ankle

Moving in a single plane, the hinge joint allows the foot's dorsiflexion and plantarflexion – the two main movements of the ankle.

  • Dorsiflexion − allows the foot to move backwards. When you try to lift a football with your foot while standing, it is called dorsiflexion movement.

  • Plantarflexion − movement allows the foot to press the car's pedals or helps a ballet dancer to tiptoe. In other words, plantarflexion helps the foot to move downwards from the resting position and away from the body.

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Apart from the above two movements, with the help of the ankle joint the foot moves laterally and medially as well.

  • Inversion − the movement which allows the foot to be turned inwards (medially) or towards the body.

  • Eversion − the movement which allows the foot to be turned away or laterally from the body is called eversion.

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Structure and Function

The ankle joint forms an important part of the way one walks since it gets adapted to the walking surface. Being a synovial joint, the ankle joint is a fluid-filled joint cavity contained inside a fibrous capsule. The synovial fluid present inside the joint cavity helps in lubrication, distribution of nutrients and shock absorption.

Ligaments

Elastic bands of tissue connecting two different bones providing stability and support are called ligaments. While a set of different ligaments connect several bones in the ankle region, there are three main sets of ligaments that connect the main bones of the ankle – tibia, fibula and talus.

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  • Tibiofibular ligaments − Tibiofibular ligaments as the name suggests, it connects the tibia and the fibula on the anterior side. Other than this, three other ligaments connect the tibia and fibula on three different sides of the joint. These four ligaments are together called Syndesmotic ligaments.

  • Lateral collateral ligaments − This ligament connects the fibula to the heel bone or calcaneus giving lateral stability to the ankle.

  • Deltoid ligaments − Tibiofibular ligaments these ligaments are also known as the medial ligaments which form the bulge on the inside of the ankle. Starting from the end of the tibia, four ligaments spread out to connect the talus, calcaneus and the navicular bones (this bone acts as a bridge between the talus on one side and the three shorter bones on the other, which go on to connect the toe bones).

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Functions of Ligaments in the Ankle

Ligaments help in a variety of functions of the ankle. The functions of the ligaments range from controlling dorsiflexion, plantarflexion, eversion and inversion. It resists the anterior and posterior displacement of the talus concerning the tibia and fibula. It also helps in supporting the ankle joint.

Muscles of the Ankle

Muscles originate from the lower leg and travel through the ankle joint to provide active support. Tendons are fibrous connective tissue that connects the muscles and the bone. The major muscles that help to push the foot downwards and stand on the toe are called gastrocnemius and soleus (calf) muscles. These muscles join at the ankle to form the Achilles tendon.

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Ankle Pain

Any discomfort or pain in the ankle region leads to pain in the ankle. It could be an injury, normal wear and tear and arthritis that can cause pain or stiffness anywhere in and around the ankle region.

Causes of Ankle Pain

  • Sprains − When the ankle violently rolls out of normal position, it might lead the ligaments to stretch or tear leading to sprains in the ankle.

  • Fracture − Any injury causing one or more bones to fracture might lead to intense pain in the ankle.

  • Gout − Usually, excess uric acid is flushed out from the body by urine. But when the uric acid level increases in the body, it will form as crystals and settle in the joint. When such uric acid crystals settle in the ankle, it leads to gout in the ankle which can be very painful. Gout is a type of arthritis.

  • Arthritis − When cartilage, a soft tissue that cushions the bone breaks down, it will lead to arthritis. Injuries, wear and tear and age-related issues might lead to arthritis.

One of the main joints in supporting our body weight and helping us walk needs some special attention. Doing the right number of exercises and workouts helps maintain this complex system aiding flexibility and strength.

FAQs

Qns 1. What are the major bones that form the ankle?

Ans. Three bones form the ankle joint – tibia, fibula and talus.

Qns 2. What are a subtalar joint and true ankle joint?

Ans. The ankle joint is a combination of two joints – the true ankle joint and the subtalar joint. While the true ankle joint is formed by three bones, the subtalar joint lies just below the true ankle joint, which consists of the talus on top and the calcaneus (heel bone) at the bottom.

Qns 3. What are dorsiflexion and plantarflexion?

Ans. Dorsiflexion allows the foot to move backwards. When you try to lift a football with your foot while standing, it is called dorsiflexion movement.

Plantarflexion allows the foot to press the car's pedals or helps a ballet dancer to tiptoe. In other words, plantarflexion helps the foot to move downwards from the resting position and away from the body.

Qns 4. What are eversion and inversion?

Ans. The movement that allows the foot to be turned inwards (medially) or towards the body is called inversion

The movement which allows the foot to be turned away or laterally from the body is called eversion.

Qns 5. What are the ligaments and muscles involved in the ankle?

Ans. Elastic bands of tissue connecting two different bones providing stability and support are called ligaments. there are three main sets of ligaments - tibiofibular ligaments, lateral collateral ligaments, and deltoid ligaments

The major muscles that help to push the foot downwards and stand on the toe are called gastrocnemius and soleus (calf) muscles. These muscles join at the ankle to form the Achilles tendon.

Qns 6. What are different kinds of ankle pain and its causes?

Ans. An injury, normal wear and tear and arthritis can cause pain or stiffness anywhere in and around the ankle region. Sprain, fracture, arthritis and gout are some of the common causes of ankle pain.

raja
Updated on 13-Oct-2022 11:19:47

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