Injury to the tarsometatarsal (TMT) joint is of concern to athletes, but the mechanism of injury remains unknown. This limits the design of effective countermeasures. As a step toward elucidating the mechanics of these injuries, this paper details an experimentally produced TMT sprain that disrupted the first ray at the distal end of the medial cuneiform with additional navicular‐cuneiform instability. The sprain was generated through both axial load and rotation. A material testing machine was used to axially load the specimen quasi‐statically, to maintain that load during testing, and to impart a pre‐determined axial rotation (twist) to the foot. A foot fixture was designed to hold the specimen in plantarflexion with the toes in hyperextenion. Rotation was imposed such that the hind‐foot was pronated with respect to the fore‐foot. Four male, cadaver feet (65 – 79 years old) were tested at axial loads ranging from 500 N – 800 N with rotation from 10° – 45°. All four feet were examined for injury post‐test by a surgeon. Instability was found in three of the four specimens along the first ray at the proximal and distal ends of the medial cuneiform. Peak loads of 795 – 1103 N and moments of 13 – 27 Nm were recorded.