A patient has an injured finger and cannot flex the distal phalanx. Which tendon is most likely affected?

• A. Extensor digitorum indicis
• B. Flexor digitorum profundus
• C. Flexor digitorum superficialis
• D. Extensor digitorum tendon

Answer: (B)

The scenario describes a patient who is unable to flex the distal phalanx of the finger, which suggests that a specific tendon responsible for flexing the fingertips is compromised. The Flexor digitorum profundus tendon is the crucial structure in this case because it primarily facilitates the flexion of the distal interphalangeal (DIP) joints, allowing the distal phalanx to bend.

The Flexor digitorum profundus is the only tendon that directly connects to the distal phalanx and is capable of flexing it. If this tendon is damaged or disrupted, flexion at the distal phalanx would be lost while flexion at proximal joints may remain intact, as would be the case with isolated injuries.

In contrast, the other tendons listed are not responsible for direct flexion of the distal phalanx. The Extensor digitorum and Extensor digitorum indicis tendons are responsible for extending the fingers rather than flexing them. The Flexor digitorum superficialis tendon primarily flexes the proximal interphalangeal (PIP) joints, but it does not flex the distal phalanx on its own since it inserts at the middle phalanx.

Hence, the most likely affected tendon