Final answer:
The typical site for a capillary puncture in an adult is the ring finger, which is preferred due to its good blood flow and lower likelihood of calluses and sensitivity.
Step-by-step explanation:
The typical site for a capillary puncture in an adult is the ring finger. When performing a capillary blood collection, healthcare professionals often prefer the ring finger's distal phalanx as it is less prone to injury and generally has a site with good blood flow that is not overused like the index finger or the thumb. It is important to avoid the thumb as it has a pulse and tends to have thicker, calloused skin, while the index finger is more sensitive and commonly used for daily tasks, which can make it also more prone to callusing.