Ultrasound wave propagation in the articular cartilage layer is considered. The cartilage is modeled by a nonhomogeneous linearly elastic layer of constant thickness. The resonances for the corresponding acoustic propagator are studied. It is shown that the resonances are asymptotically distributed along a straight line parallel to the real axis on the unphysical sheet of the complex frequency plane. The spacing between two successive resonances turns out to be sensitive to articular cartilage degeneration.