After completing “The Ankle Joint” section, you will be able:
- To describe the 3 bones
- To identify the 7 tarsal bones
- To summarise the 2 joints and their action
- To explain the 2 main ligaments
- To validate knowledge by completing the quiz
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The ankle joint is made from 3 bones:
- Tibia: medial bone of the lower limb
- Fibula: lateral bone of the lower limb
- Talus: inferior to the tibia and fibula
TIP: * ANALOGY * The Fibula is thin like a Flute. The Tibia is thick like a Tuba.
TOP TIP: FibuLA = LAteral
Bones of The Ankle Joint
7 TARSAL (FEET) BONES
(superior → inferior, medial → lateral)
TIP: * Mnemonic Alert * Tiger Cubs Need MILC
- T: Talus
- C: Calcaneus
- N: Navicular
- M: Medial cuneiform
- I: Intermediate cuneiform
- L: Lateral cuneiform
- C: Cuboid
Hinge-type and synovial joint based on the action:
1. Subtalar joint
- Bones = calcaneus and talus
- Action = eversion and inversion
2. “True” ankle joint
- Bones = tibia, fibula, and talus
- Action = dorsiflexion and plantarflexion
2 LIGAMENTS (REMEMBER: LIGAMENTS = BONE → BONE)
There are 2 main ligaments of the ankle joint:
1. Medial ligament:
- It consists of four separate ligaments, which fan out from the medial malleolus, attaching to the talus, calcaneus and navicular bones.
- Action = Resists over-eversion of the foot.
2. Lateral ligament:
- Originates from the lateral malleolus.
- Action = Resists over-inversion of the foot.
- It is comprised of three distinct and separate ligaments:
- Anterior talofibular: weak ligament. lateral malleolus → lateral part of the talus
- Posterior talofibular: strong ligament. lateral malleolus → posterior part of the talus
- Calcaneofibular: lateral malleolus → calcaneus
TIP: * ANALOGY * THE ANKLE RING
In the coronal plane, the ankle joint and ligaments can be visualised as like a polo/ring:
- UPPER RING: articular surfaces of tibia and fibular
- SIDES: medial and lateral ligaments
- LOWER RING: subtalar joint (calcaneus and talus)
When a polo mint breaks, it breaks in more than one place. This mechanism of breakage is similar to the ankle ring, where a fracture of one part causes damage to another part.
Radiopaedia. (2017). Tarsal bones (mnemonic). [online]. Available at: https://radiopaedia.org/articles/tarsal-bones-mnemonic [accessed 1 March 2017].
Teach Me Anatomy. (2017). The Ankle Joint. [online]. Available at: http://teachmeanatomy.info/upper-limb/joints/elbow-joint/ [accessed 1 March 2017].