The free lateral arm flap has become a well-defined and reliable flap for various reconstructive purposes. Little attention has been paid, however, to the possibility of preservation of the posterior cutaneous nerve of the forearm (nervus cutaneus antebrachii posterior) sacrifice of which results in numbness of the dorsal part of the forearm. In this study, an anatomical dissection showed that in many cases it would be possible to preserve the nerve. We did 23 free lateral arm flaps in 22 patients during the period 1989-1994. The maximum flap length was 40 cm. Standard maximum width in most cases was 6 cm, and by using a new expansion technique it reached 10 cm in one case. Furthermore, with meticulous dissection the posterior cutaneous nerve of the forearm was either preserved or cut and rejoined in 21 patients, so minimising sensory loss at the donor site.