A Three-Dimensional Biomechanical Analysis of the Cat Ankle Joint Complex: I. Active and Passive Postural Mechanics

in Journal of Applied Biomechanics
View More View Less
Restricted access

Purchase article

USD  $24.95

Student 1 year online subscription

USD  $88.00

1 year online subscription

USD  $118.00

Student 2 year online subscription

USD  $168.00

2 year online subscription

USD  $224.00

Muscle actions are often defined with respect to a single anatomical reference plane based on a “predominant” functional activity. Yet animals must control posture and movement within a three-dimensional (3-D) environment, exerting control over more than one reference plane when responding to a 3-D array of perturbing forces. Consequently, enhanced knowledge concerning the 3-D torque capabilities of certain appendicular muscles might provide for greater understanding of the biomechanical basis for motor control. We propose that the cat postural control mechanism utilizes the inherent 3-D mechanical actions of ankle flexors and extensors to maintain extra-saggital joint stiffness. We used a 6 degree-of-freedom force-moment sensor to assess the effect of ankle joint orientation on the 3-D nature of isometric joint torques evoked by electrical stimulation of muscles crossing the AJC in the deeply anesthetized cat. An orthogonal axis system was established at the designated ankle rotation center, such that pitch (defining flexion-extension), yaw (abduction-adduction), and roll (inversion-eversion) axis torques were calculated. Experimental results show that the classical cat ankle flexor and extensors evoke large extra-sagittal torques as well. Also, the hind limb levering system stabilizes the AJC against large yaw and roll rotations away from the control position.

J.H. Lawrence III is with the Center for Biomedical Engineering at the University of Kentucky, Lexington, KY 40506-0070. T.R. Nichols is with the Department of Physiology at Emory University, Atlanta, GA 30322.

All Time Past Year Past 30 Days
Abstract Views 57 45 7
Full Text Views 1 1 1
PDF Downloads 2 2 2