## Correct Answer: C. Jersey finger & baseball finger Jersey finger and baseball finger represent two distinct closed soft-tissue injuries of the hand with characteristic mechanisms and clinical presentations. Jersey finger (image A) is an avulsion of the flexor digitorum profundus (FDP) tendon from its insertion at the base of the distal phalanx, classically occurring when a player's finger is forcibly extended while attempting to grasp an opponent's jersey during contact sports. The mechanism is sudden passive extension of a flexed DIP joint against active flexion. Baseball finger (image B), also called mallet finger, is an avulsion or rupture of the extensor digitorum communis (EDC) tendon at its insertion on the dorsal base of the distal phalanx, typically caused by a direct blow to the tip of an extended finger—such as when a baseball strikes the fingertip. Clinically, jersey finger presents with loss of DIP flexion and a characteristic "lump" in the palm (the retracted FDP tendon), while baseball finger shows loss of DIP extension with a characteristic "mallet" deformity (drooping fingertip). These injuries are common in Indian contact sports (kabaddi, wrestling) and require early surgical intervention for jersey finger but conservative splinting for most mallet fingers. The distinction is critical because jersey finger demands urgent repair to prevent permanent loss of grip strength, whereas mallet finger often heals with conservative management. ## Why the other options are wrong **A. Mallet finger & boxer fracture** — This pairs two injuries that do not match the clinical presentation in the images. Mallet finger is an extensor tendon injury (correct for image B), but boxer fracture is a metacarpal neck fracture (typically 5th metacarpal), not a tendon avulsion. The images show soft-tissue injuries, not fractures. This option conflates a tendon injury with a bone injury. **B. Mallet finger & Jersey finger** — This reverses the correct pairing. While both are valid hand injuries, mallet finger (EDC avulsion) does not match image A, which shows the characteristic presentation of jersey finger (FDP avulsion with loss of DIP flexion). Jersey finger is the flexor-side injury, mallet finger is the extensor-side injury. The mechanism and clinical findings are opposite. **D. Boxer fracture & march fracture** — Both options are fractures, not tendon avulsions. Boxer fracture is a metacarpal neck fracture; march fracture is a stress fracture of the metatarsal shaft. Neither matches the soft-tissue tendon injuries shown in the images. This option completely misidentifies the pathology as skeletal rather than ligamentous/tendinous. ## High-Yield Facts - **Jersey finger** = FDP avulsion from distal phalanx base; loss of DIP flexion; requires urgent surgical repair within 7–10 days. - **Baseball (mallet) finger** = EDC avulsion from dorsal distal phalanx; loss of DIP extension; managed conservatively with splinting in most cases. - Jersey finger mechanism: sudden passive extension of a flexed DIP joint (e.g., grabbing opponent's jersey in contact sports). - Mallet finger mechanism: direct blow to extended fingertip (e.g., ball striking finger or crush injury). - Jersey finger presents with palpable lump in palm (retracted FDP tendon); mallet finger presents with drooping fingertip and loss of active DIP extension. - **Leddy & Packer classification** of jersey finger guides timing of surgical repair based on tendon retraction level. ## Mnemonics **FDP vs EDC injury site** **F**lexor = **F**ront (palm lump in jersey finger); **E**xtensor = **E**xtension loss (mallet finger). Jersey finger = flexor side (volar), mallet = extensor side (dorsal). **Jersey vs Mallet mechanism** **J**ersey = **J**erk (sudden passive extension); **M**allet = **M**echanical blow (direct trauma to fingertip). Jersey is a pulling injury; mallet is a striking injury. ## NBE Trap NBE often pairs mallet finger with jersey finger as a distractor because both are common hand injuries affecting the DIP joint, but they involve opposite tendons (extensor vs flexor) and require opposite management (conservative vs surgical). Students who confuse the mechanism or anatomy may select option B. ## Clinical Pearl In Indian contact sports (kabaddi, wrestling, football), jersey finger is a surgical emergency—delay beyond 10 days makes repair technically difficult and functional recovery poor. Mallet finger, conversely, is managed conservatively with 6–8 weeks of DIP splinting, making early recognition of the distinction clinically vital for triage and outcome. _Reference: Bailey & Love Ch. 48 (Hand Surgery); Harrison Ch. 330 (Musculoskeletal Injuries)_
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