To remember the structures of anatomical snuff box, look at your right hand and extend your thumb. You see three prominent tendons. The tendon in Between is a Brevis tendon--EXTENSOR POLLICIS BREVIS. The tendon that meets it from extensor surface is therefore EXTENSOR POLLICIS LONGUS. The remaining tendon going in different direction of Extensor Pollicis Brevis is therefore ABDUCTOR POLLICIS LONGUS. Note that the longus goes parallel and brevis connverges on both ends.
