Synergists of the Hand

Question 1

Extension of the Second through Fifth Fingers

Answer 1

1. Extensor digitorum
   
   2. Lumbricals
   3. Dorsal interossei (2nd - 4th; assists)
   4. Palmar interossei (2nd, 4th, 5th; assists)
   5. Extensor indicis (2nd)*

Question 2

Flexion of the Second through Fifth Fingers

Answer 2

1. Flexor digitorum superficialis
   
   2. Flexor digitorum profundus
   3. Flexor digiti minimi brevis (5th)*
   4. Lumbricals
   5. Dorsal interossei (2nd - 4th; assists)
   6. Palmar interossei (2nd, 4th, 5th; assists)

Question 3

Thumb Flexion

Answer 3

1. Flexor pollicis longus
   
   2. Flexor pollicis brevis*
   3. Adductor pollicis (assists)
   4. Palmar interossei (1st; assists)*

Question 4

Thumb Extension

Answer 4

1. Extensor pollicis longus
   
   2. Extensor pollicis brevis
   3. Abductor pollicis longus
   4. Palmar interossei (1st; assists)

Question 5

Thumb Opposition

Answer 5

1. Opponens pollicis
   
   2. Flexor pollicis brevis (assists)*
   3. Abductor pollicis brevis (assists)*