A rugby player grabs another player's jersey and feels sudden pain in his ring finger as it is forcefully pulled into extension while he is gripping. He can flex the PIP joint normally but cannot flex the DIP joint of that finger. The structure injured is the:

• A Flexor digitorum superficialis tendon
• B Central slip of the extensor expansion
• C Flexor digitorum profundus tendon avulsed from the distal phalanx ✓
• D Volar plate of the proximal interphalangeal joint

Explanation

Jersey finger is avulsion of the flexor digitorum profundus from its insertion on the base of the distal phalanx, caused by forced extension of a digit during active flexion. Because FDS still flexes the PIP joint but nothing flexes the DIP joint, loss of active DIP flexion localises the lesion precisely. Loss of PIP flexion would implicate superficialis, and the central slip produces a boutonniere pattern, eliminating options A and B.

Reference: Green's Operative Hand Surgery, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.