What is indicated by a lack of plantar flexion in the Thompson Test?

A lack of plantar flexion during the Thompson Test is indicative of a rupture of the Achilles tendon. The Thompson Test is performed by having the patient lie prone, and the examiner squeezes the calf muscle. In a healthy individual, this action will cause the foot to exhibit plantar flexion due to the intact Achilles tendon. When there is a rupture, the calf muscle will not result in the expected movement, demonstrating a loss of function.

This test is specifically used to assess the integrity of the Achilles tendon, making the presence of plantar flexion a sign that the tendon is intact. A lack of this movement is a direct indication of its rupture, which is a common injury in activities that involve sudden acceleration or jumping. Other options do not relate to the specifics of the test and the actions being assessed, as only the Achilles tendon is involved in producing plantar flexion in this context.