The terms valgus and varus refer to angulation (or bowing) within the shaft of a bone or at a joint.
It is determined by the distal part being more medial or lateral than it should be. Whenever the distal part is more lateral, it is called valgus. Whenever the distal part is more medial, it is called varus. Therefore, when the apex of a joint points medially, the deformity, if any, would be called valgus, as the distal part points laterally.
It is important to bear in mind that the most proximal part of a bone or joint is the reference point and that varus and valgus angles are relative to the angle in a normal situation, which need not be zero.
The L of "lateral" is also in valgus, but not in varus. When also remembering that the direction of the distal part is key: distal (more) lateral means valgus and distal (more) medial means varus.
coxa valga and coxa vara:
- relation of the femoral shaft to the femoral neck
- coxa vara: femoral neck is in a relatively flat position
- coxa valga: femoral neck is relatively steep
genu varum and genu valgum:
- depends on the direction of distal part of the tibia (which is the distal component of the knee joint)
- genu valgum: distal part pointing laterally
- genu varum: distal part pointing medially
hindfoot varus and hindfoot valgus:
- the posterior aspect of the calcaneus is the distal part in relation to the talocalcaneal articulation
- neutral talocalcaneal angle is between 25 and 40 degrees "varus", meaning that normally the posterior part of the calcaneus is positioned medial to the anterior part
- laterally pointed distal part of the proximal phalanx of the first digit
- first metatarsophalangeal joint itself points medially
cubitus valgus and cubitus varus:
- cubitus valgus: distal part of the forearm points laterally
- cubitus varus: distal part of the forearm points medially
- remember that terminology concerning the forearm is related to the anatomical position, which has the volar surface of the hand turned anteriorly, putting the radius and the thumb laterally and the ulna medially