Final answer:
The term for finger IP extension associated with Test 1 and Test 2 likely relates to the extensor mechanism in the fingers, particularly the Extensor Digitorum muscle and the extensor expansion over the phalanges.
Step-by-step explanation:
The term related to finger IP extension in the context of the described tests likely refers to the action of the extensor muscles of the fingers, particularly the Extensor Digitorum. This muscle helps in extending the interphalangeal (IP) joints of the fingers. The description provided suggests that the extensor expansion, which is a tendinous network that allows the extensor digitorum to insert onto the phalanx bones of the finger, is located on the first phalanx on the side opposite finger 3 for each finger.
During Test 1 and Test 2, which are unspecified in the question but might refer to clinical tests for evaluating the integrity and function of the extensor tendons or diagnosing potential conditions involving finger movement, this extensor mechanism contributes to the extension of the IP joints. A commonly recognized condition associated with dysfunction or injury in this region is mallet finger, a deformity that occurs when the distal phalanx of the finger cannot be actively extended.