Which muscles contribute to producing a hook fist?

Which muscles contribute to producing a hook fist?

• A. Flexor digitorum profundus
• B. Flexor digitorum superficialis
• C. Extensor digitorum
• D. All of the above

Answer: (D)

A hook fist is formed by curling the fingers around an object with the distal joints flexed while the metacarpophalangeal joints stay extended to create the hook shape. The flexor digitorum profundus flexes the DIP (and also supports MCP flexion), and the flexor digitorum superficialis flexes the PIP (and helps with MCP as well). To keep the hand in a hooked position around the object, the extensor digitorum must extend the metacarpophalangeal joints (via the extensor mechanism), preventing the MCPs from collapsing into flexion. The coordinated action of these muscles across the finger joints enables the hook grip, so all three contribute.

A hook fist is formed by curling the fingers around an object with the distal joints flexed while the metacarpophalangeal joints stay extended to create the hook shape. The flexor digitorum profundus flexes the DIP (and also supports MCP flexion), and the flexor digitorum superficialis flexes the PIP (and helps with MCP as well). To keep the hand in a hooked position around the object, the extensor digitorum must extend the metacarpophalangeal joints (via the extensor mechanism), preventing the MCPs from collapsing into flexion. The coordinated action of these muscles across the finger joints enables the hook grip, so all three contribute.