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. Author manuscript; available in PMC: 2013 May 27.
Published in final edited form as: J Nov Physiother. 2013 Mar 1;Suppl 4(1):11732. doi: 10.4172/2165-7025.S4-001

Figure 1.

Figure 1

Five constraints $′ s are collectively reciprocal to the instantaneous screw $. The instantaneous motion of the knee is guided by the constraints of the anterior cruciate ligaments (ACL), posterior cruiciate ligament (PCL), medial collateral ligament (MCL), and articular contact in the medial (P1) and lateral (P2) compartments. Note that no combination of the constraint forces that might be generated at the $′ will result in a turning at the $, and no angular velocity at the $ will cause the constraint force to do any work at the points on the medial and lateral contact locations (used with permission and adapted from Kim and Kohles, 2012 [9]).