Describe the etiology.
Eversion or inversion injury
Axial loading (e.g., fall from a height, motor vehicle collision)
Describe the types of ankle #.
Lateral malleolar fracture
Medial malleolar fracture
Posterior malleolar fracture
Bimalleolar fracture: fractures of the lateral and medial malleoli
Trimalleolar fracture: fractures of the lateral, medial, and posterior malleoli
Pilon fracture: fracture of the distal tibia involving the articular surface of the talocrural joint
Maisonneuve fracture: fracture of the proximal fibula associated with disruption of the distal tibiofibular syndesmosis and medial malleolar injury (i.e., medial malleolar fracture, deltoid ligament rupture) 
Other: Volkmann triangle refers to an avulsion fracture of the posterolateral tibial lip
Describe the ankle # stability.
The ankle becomes increasingly unstable with worsening severity of injury. Generally, fractures at two or more sites are unstable.
Usually stable: isolated lateral malleolar fracture or isolated medial malleolar fracture
Usually unstable: posterior malleolar fracture, bimalleolar fracture, Maisonneuve fracture
Always unstable: trimalleolar fracture, pilon fracture
List clinical features.
Local pain, swelling and hematoma
Tenderness, especially in the area of the malleoli, the syndesmosis, and the posterior aspect of the ankle joint
Restricted range of movement
Skin abnormalities (lacerations, discolorations, tenting, or blistering)
If separation of the ankle mortise elements occurs: lateral displacement of the foot
In some cases, accompanying injury (e.g., fracture of the proximal fibula, knee, or foot)