Thumb deformity: Any malformation or difference in appearance of the thumb. The deformity may result from trauma, a disease process (such as rheumatoid arthritis) or may be an inherited anomaly.
Triphalangeal thumb: A medical term used to describe a thumb which has three bones instead of the normal two. The anomaly can occur on its own (isolated triphalangeal thumb) or may be associated with other defects. Usually both thumbs are affected.
Upper limb conditions: Any medical condition affecting the upper limbs, i.e. the arms, elbows, hands, etc.