What is the normal capsular pattern for the interphalangeal joints of digits 2-5?

• A. Flexion = Extension
• B. Flexion > Extension
• C. Abduction and Adduction limited
• D. Flexion > Extension (+/-2:1)

Answer: (D)

Interphalangeal joints (digits 2–5) are hinge joints, and their normal capsular pattern is that flexion is limited more than extension. The amount of limitation in flexion tends to be about twice that of extension, so the best description is flexion limited more than extension with a rough 2:1 ratio. Abduction and adduction aren’t primary movements at these joints, so those directions aren’t part of the typical capsular pattern. That’s why the description Flexion > Extension (+/-2:1) fits best.