The infrapatellar synovail fold: a cause for confusion in the evaluation of the anterior cruciate ligament.

The anterior cruciate ligament may be simulated by the normal infrapatellar synovial fold or ligamentum mucosum. With the aid of lateral tomography, the expected course and insertion of the structures can usually be differentiated. This distinction is important, since a torn anterior cruciate ligament can be overlooked and lead to a delay in appropriate therapy.