pronation

[Cf. F. pronation.]
(Physiol.) (a) The act of turning the palm or palmar surface of the forefoot downward. (b) That motion of the forearm whereby the palm or palmar, surface is turned downward. (c) The position of the limb resulting from the act of pronation. Opposed to supination.

1. Movement of the forearm so that the palm faces downwards. Pronation is the natural position of the forearm when a person is standing in a relaxed position.

2. During running or walking, an inward rolling motion just after the heel strikes the ground and when the weight is shifted to the middle of the foot. It is a natural action which serves as a shock-absorbing and an energy-return mechanism. However, overpronation can become a problem. When the foot rolls too far inwards, the foot arches, ankle, or knee may be damaged. Special shoes, usually with a firmer midsole, have been designed for those who tend to over-pronate. Compare supination.

1. An inward rotation of the forearm so that the palm is facing posteriorly or inferiorly (i.e. backward or downward). During pronation, the distal end of the radius moves across the ulna towards the midline. Pronation is the natural position (but not the anatomical position) of the forearm when a person is standing in a relaxed position. Compare supination.

2. During the midstance of the weight-bearing phase of running and walking, a tendency for eversion and abduction to occur as the foot moves into dorsiflexion. Pronation serves as a shock-absorbing and an energy-return mechanism.

Pronation