Interossei

Question 1

Palmar Interossei

Answer 1

O: shaft of each metacarpal

I: extensor aponeurosis of finger of origin

A: adduction of respective finger, flexion of metacarpalphalangeal joints, extension of interphalangeal joints

In: ulnar nerve

Question 2

Dorsal Interossei

Answer 2

O: adjacent surfaces of two metacarpals

I:
#1 - proximal phalanx of radial side of index inger
#2-4 - proximal phalanx on the radial side of middle, ulnar side of middle, and ulnar side of ring fingers, respectively + extensor aponeurosis

A: abduction of index, middle, and ring fingers + flexion of metacarpalphalangeal joints

In: ulnar nerve