|Varus Deformity MRI and photograph|
The terms varus and valgus always refer to the direction that the distal segment of the joint points.
For example, in a VARUS deformity of the knee, the distal part of the leg below the knee is deviated inward, resulting in a bowlegged appearance. Conversely, a valgus deformity at the knee results in a knock-kneed appearance, with the distal part of the leg deviated outward.
The terminology is made confusing by the etymology of these words.
- In Latin, valgus actually means "knock-kneed" and varus means "bowlegged."
- In a knock-kneed person, the femur is deviated inward in relation to the hip, so the term varus is correctly applied for the hip, as it refers to the distal segment being angled inward.
- But in the same knock-kneed person, the opposite situation is found at the knee, with the distal segment now being deviated outward, so the term valgus is used for the knee.
- It is correct for a knock-kneed deformity to be called both a varus deformity at the hip/femur and a valgus deformity at the knee/tibia, although the common terminology is to refer to it as genu valgum.
If this is confusing, just remember that "varus = inward" and "valgus = outward" and always refers to the direction that the distal part of the joint points.
When the terminology specifies a bone rather than a joint, the bone is taken to be the distal segment of a joint. Thus, a varus deformity of the tibia refers to the femur/tibia joint (the knee) and not the ankle joint.
- Hip: coxa vara — the angle between the ball and the shaft of the femur is reduced, resulting in a limp.
- Knee: genu varum (from Latin genu = knee) — the tibia is turned inward in relation to the femur, resulting in a bowlegged deformity.
- Ankle: talipes varus (from Latin talus = ankle and pes = foot) — inward turning of the heel, resulting in clubfoot with the person walking on the outer part of the foot.
- Toe: hallux varus (Latin hallux = big toe) — inward deviation of the big toe away from the second toe.
- Elbows: cubitus varus (Latin cubitus = elbow) — turned inward elbows