The proximal end of the palmar aponeurosis.

The proximal end of the palmar aponeurosis receives two important contingents of fibres from the flexor carpi ulnaris tendon. The superficial contingent blends with the fibres of palmaris longus; the deep contingent runs on the surface of the pisohamate ligament and connects the flexor retinaculum to the palmar aponeurosis. In congenital absences of the palmaris longus, flexor carpi ulnaris completely takes over as the longitudinal tensor of the palmar aponeurosis.