Numerous condtions, notably nerve entrapment syndromes, account for symptoms in the upper extremities. Some are quite common and familiar, while others are remote. In this article, an algorithmic approach has been utilized to describe a broad variety of neurological and non-neurological conditions and to provide readers with an overview of each. The algorithm is intended to be used by the non-specialist who is interested in expanding his list of differential diagnoses for a patient’s complaint. It is a reference tool, not a cookbook for diagnosis. Likewise, a planar diagram cannot provide a definitive diagnosis. Common sense and experience will do that.