A trimalleolar fracture is a fracture of the ankle

Ankle

The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...

 that involves the lateral malleolus, medial malleolus and the distal posterior aspect of the tibia

Tibia

The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....

, which can be termed the posterior malleolus.

The three aforementioned parts of bone articulate with the talus bone

Talus bone

-External links:* *...

 of the foot

Foot

The foot is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is a separate organ at the terminal part of the leg made up of one or more segments or bones, generally including claws...

. Strictly speaking, there are only two malleoli (medial and lateral), but the term trimalleolar is used nevertheless and as such is a misnomer

Misnomer

A misnomer is a term which suggests an interpretation that is known to be untrue. Such incorrect terms sometimes derive their names because of the form, action, or origin of the subject becoming named popularly or widely referenced—long before their true natures were known.- Sources of misnomers...

.

Treatment

Surgical repair is required, and because there is no lateral restraint of the foot, the ankle cannot bear any weight while the bone knits. This typically takes six weeks in an otherwise healthy person.

External links

• X-ray of a trimalleolar fracture - ucsf.edu.
• Trimalleolar fracture - wheelessonline.com