Surgical Tutorial – Flexor Digitorum Superficialis to Anterior Interosseous Nerve Transfer. For isolated anterior interosseous nerve palsies, the nerve to the flexor digitorum superficialis (FDS) is an available donor to innervate the anterior interosseous nerve (AIN) for transfer. The FDS and AIN branch are found branching from the median nerve within the same upper-middle forearm region. The nerve to the FDS branches from the median nerve on its ulnar aspect while the AIN branches from the median nerve on its radial aspect. Prior to the nerve transfer, the median nerve is decompressed and exposed by step-lengthening the superficial head of pronator teres, releasing the deep head of pronator teres, and releasing the proximal tendinous arch of FDS. The FDS to AIN nerve transfer is an available option to restore AIN function.