Which term refers to abnormal widening and thickening of the ends of fingers and toes?

The term that describes the abnormal widening and thickening of the ends of fingers and toes is known as clubbing. This condition often occurs in response to chronic hypoxia or low oxygen levels in the body, commonly associated with respiratory and cardiovascular diseases. When clubbing occurs, the nails may also curve downward, and the fingertips may become enlarged, leading to a characteristic appearance that can indicate underlying health issues such as lung disease or heart problems.

The other terms relate to different medical conditions. Dyspnea refers to the feeling of shortness of breath or difficulty in breathing, which does not relate to changes in the structure of the fingers or toes. Orthopnea is a condition where a patient experiences difficulty breathing when lying flat, which is also unrelated to fingertip morphology. Cyanosis describes a bluish discoloration of the skin or mucous membranes due to insufficient oxygen in the blood, but again, it pertains to coloration rather than physical changes in the fingers or toes. Thus, clubbing is the only option that accurately describes the condition in question.